Change epoll_del() to accept the epoll file descriptor directly instead of the full context structure. This simplifies the interface and aligns with the threading refactoring by reducing dependency on the context structure for basic epoll operations as we will manage an epollfd per thread. Signed-off-by: Laurent Vivier Reviewed-by: David Gibson --- icmp.c | 2 +- tap.c | 2 +- tcp.c | 6 +++--- tcp_splice.c | 4 ++-- udp_flow.c | 4 ++-- util.c | 6 +++--- util.h | 2 +- vhost_user.c | 6 +++--- 8 files changed, 16 insertions(+), 16 deletions(-) diff --git a/icmp.c b/icmp.c index 6dffafb0bf54..bd3108a21675 100644 --- a/icmp.c +++ b/icmp.c @@ -151,7 +151,7 @@ unexpected: static void icmp_ping_close(const struct ctx *c, const struct icmp_ping_flow *pingf) { - epoll_del(c, pingf->sock); + epoll_del(c->epollfd, pingf->sock); close(pingf->sock); flow_hash_remove(c, FLOW_SIDX(pingf, INISIDE)); } diff --git a/tap.c b/tap.c index f3d1f66041f8..9812f120d426 100644 --- a/tap.c +++ b/tap.c @@ -1142,7 +1142,7 @@ void tap_sock_reset(struct ctx *c) } /* Close the connected socket, wait for a new connection */ - epoll_del(c, c->fd_tap); + epoll_del(c->epollfd, c->fd_tap); close(c->fd_tap); c->fd_tap = -1; if (c->mode == MODE_VU) diff --git a/tcp.c b/tcp.c index 0f9e9b3fdc03..745353f782f5 100644 --- a/tcp.c +++ b/tcp.c @@ -511,9 +511,9 @@ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn) if (conn->events == CLOSED) { if (conn->in_epoll) - epoll_del(c, conn->sock); + epoll_del(c->epollfd, conn->sock); if (conn->timer != -1) - epoll_del(c, conn->timer); + epoll_del(c->epollfd, conn->timer); return 0; } @@ -3476,7 +3476,7 @@ int tcp_flow_migrate_source_ext(const struct ctx *c, if (c->migrate_no_linger) close(s); else - epoll_del(c, s); + epoll_del(c->epollfd, s); /* Adjustments unrelated to FIN segments: sequence numbers we dumped are * based on the end of the queues. diff --git a/tcp_splice.c b/tcp_splice.c index 26cb63064583..666ee62b738f 100644 --- a/tcp_splice.c +++ b/tcp_splice.c @@ -204,8 +204,8 @@ static void conn_flag_do(const struct ctx *c, struct tcp_splice_conn *conn, } if (flag == CLOSING) { - epoll_del(c, conn->s[0]); - epoll_del(c, conn->s[1]); + epoll_del(c->epollfd, conn->s[0]); + epoll_del(c->epollfd, conn->s[1]); } } diff --git a/udp_flow.c b/udp_flow.c index cef3fb588bbe..84973f807167 100644 --- a/udp_flow.c +++ b/udp_flow.c @@ -51,7 +51,7 @@ void udp_flow_close(const struct ctx *c, struct udp_flow *uflow) flow_foreach_sidei(sidei) { flow_hash_remove(c, FLOW_SIDX(uflow, sidei)); if (uflow->s[sidei] >= 0) { - epoll_del(c, uflow->s[sidei]); + epoll_del(c->epollfd, uflow->s[sidei]); close(uflow->s[sidei]); uflow->s[sidei] = -1; } @@ -88,7 +88,7 @@ static int udp_flow_sock(const struct ctx *c, if (flowside_connect(c, s, pif, side) < 0) { int rc = -errno; - epoll_del(c, s); + epoll_del(c->epollfd, s); close(s); flow_dbg_perror(uflow, "Couldn't connect flow socket"); diff --git a/util.c b/util.c index c492f904b3fc..1067486be414 100644 --- a/util.c +++ b/util.c @@ -996,12 +996,12 @@ void raw_random(void *buf, size_t buflen) /** * epoll_del() - Remove a file descriptor from our passt epoll - * @c: Execution context + * @epollfd: epoll file descriptor to remove from * @fd: File descriptor to remove */ -void epoll_del(const struct ctx *c, int fd) +void epoll_del(int epollfd, int fd) { - epoll_ctl(c->epollfd, EPOLL_CTL_DEL, fd, NULL); + epoll_ctl(epollfd, EPOLL_CTL_DEL, fd, NULL); } diff --git a/util.h b/util.h index 22eaac56e719..c61cbef357aa 100644 --- a/util.h +++ b/util.h @@ -300,7 +300,7 @@ static inline bool mod_between(unsigned x, unsigned i, unsigned j, unsigned m) #define FPRINTF(f, ...) (void)fprintf(f, __VA_ARGS__) void raw_random(void *buf, size_t buflen); -void epoll_del(const struct ctx *c, int fd); +void epoll_del(int epollfd, int fd); /* * Starting from glibc 2.40.9000 and commit 25a5eb4010df ("string: strerror, diff --git a/vhost_user.c b/vhost_user.c index 223332d5018e..f8324c59cc6c 100644 --- a/vhost_user.c +++ b/vhost_user.c @@ -733,7 +733,7 @@ static bool vu_get_vring_base_exec(struct vu_dev *vdev, vdev->vq[idx].call_fd = -1; } if (vdev->vq[idx].kick_fd != -1) { - epoll_del(vdev->context, vdev->vq[idx].kick_fd); + epoll_del(vdev->context->epollfd, vdev->vq[idx].kick_fd); close(vdev->vq[idx].kick_fd); vdev->vq[idx].kick_fd = -1; } @@ -801,7 +801,7 @@ static bool vu_set_vring_kick_exec(struct vu_dev *vdev, vu_check_queue_msg_file(vmsg); if (vdev->vq[idx].kick_fd != -1) { - epoll_del(vdev->context, vdev->vq[idx].kick_fd); + epoll_del(vdev->context->epollfd, vdev->vq[idx].kick_fd); close(vdev->vq[idx].kick_fd); vdev->vq[idx].kick_fd = -1; } @@ -1093,7 +1093,7 @@ void vu_cleanup(struct vu_dev *vdev) vq->err_fd = -1; } if (vq->kick_fd != -1) { - epoll_del(vdev->context, vq->kick_fd); + epoll_del(vdev->context->epollfd, vq->kick_fd); close(vq->kick_fd); vq->kick_fd = -1; } -- 2.51.0

Move epoll_add() calls from sock_l4_sa() to the protocol-specific code (icmp.c, pif.c, udp_flow.c) to give callers more control over epoll registration. This allows sock_l4_sa() to focus solely on socket creation and binding, while epoll management happens at a higher level. Remove the data parameter from sock_l4_sa() and flowside_sock_l4() as it's no longer needed - callers now construct the full epoll_ref and register the socket themselves after creation. Signed-off-by: Laurent Vivier Reviewed-by: David Gibson --- flow.c | 10 ++++------ flow.h | 2 +- icmp.c | 15 +++++++++++---- pif.c | 32 +++++++++++++++++++++++++------- udp_flow.c | 16 ++++++++++++++-- util.c | 10 +--------- util.h | 2 +- 7 files changed, 57 insertions(+), 30 deletions(-) diff --git a/flow.c b/flow.c index feefda3ce74e..b14e9d8b63ff 100644 --- a/flow.c +++ b/flow.c @@ -163,7 +163,6 @@ static void flowside_from_af(struct flowside *side, sa_family_t af, * @type: Socket epoll type * @sa: Socket address * @sl: Length of @sa - * @data: epoll reference data */ struct flowside_sock_args { const struct ctx *c; @@ -173,7 +172,6 @@ struct flowside_sock_args { const struct sockaddr *sa; socklen_t sl; const char *path; - uint32_t data; }; /** flowside_sock_splice() - Create and bind socket for PIF_SPLICE based on flowside @@ -188,7 +186,7 @@ static int flowside_sock_splice(void *arg) ns_enter(a->c); a->fd = sock_l4_sa(a->c, a->type, a->sa, a->sl, NULL, - a->sa->sa_family == AF_INET6, a->data); + a->sa->sa_family == AF_INET6); a->err = errno; return 0; @@ -205,7 +203,7 @@ static int flowside_sock_splice(void *arg) * (if specified). */ int flowside_sock_l4(const struct ctx *c, enum epoll_type type, uint8_t pif, - const struct flowside *tgt, uint32_t data) + const struct flowside *tgt) { const char *ifname = NULL; union sockaddr_inany sa; @@ -225,12 +223,12 @@ int flowside_sock_l4(const struct ctx *c, enum epoll_type type, uint8_t pif, ifname = c->ip6.ifname_out; return sock_l4_sa(c, type, &sa, sl, ifname, - sa.sa_family == AF_INET6, data); + sa.sa_family == AF_INET6); case PIF_SPLICE: { struct flowside_sock_args args = { .c = c, .type = type, - .sa = &sa.sa, .sl = sl, .data = data, + .sa = &sa.sa, .sl = sl, }; NS_CALL(flowside_sock_splice, &args); errno = args.err; diff --git a/flow.h b/flow.h index cac618ad0ca1..ef138b83add8 100644 --- a/flow.h +++ b/flow.h @@ -167,7 +167,7 @@ static inline bool flowside_eq(const struct flowside *left, } int flowside_sock_l4(const struct ctx *c, enum epoll_type type, uint8_t pif, - const struct flowside *tgt, uint32_t data); + const struct flowside *tgt); int flowside_connect(const struct ctx *c, int s, uint8_t pif, const struct flowside *tgt); diff --git a/icmp.c b/icmp.c index c26561da80bf..56dfac6c958e 100644 --- a/icmp.c +++ b/icmp.c @@ -170,10 +170,10 @@ static struct icmp_ping_flow *icmp_ping_new(const struct ctx *c, { uint8_t proto = af == AF_INET ? IPPROTO_ICMP : IPPROTO_ICMPV6; uint8_t flowtype = af == AF_INET ? FLOW_PING4 : FLOW_PING6; - union epoll_ref ref = { .type = EPOLL_TYPE_PING }; union flow *flow = flow_alloc(); struct icmp_ping_flow *pingf; const struct flowside *tgt; + union epoll_ref ref; if (!flow) return NULL; @@ -194,9 +194,7 @@ static struct icmp_ping_flow *icmp_ping_new(const struct ctx *c, pingf->seq = -1; - ref.flowside = FLOW_SIDX(flow, TGTSIDE); - pingf->sock = flowside_sock_l4(c, EPOLL_TYPE_PING, PIF_HOST, - tgt, ref.data); + pingf->sock = flowside_sock_l4(c, EPOLL_TYPE_PING, PIF_HOST, tgt); if (pingf->sock < 0) { warn("Cannot open \"ping\" socket. You might need to:"); @@ -208,6 +206,15 @@ static struct icmp_ping_flow *icmp_ping_new(const struct ctx *c, if (pingf->sock > FD_REF_MAX) goto cancel; + ref.type = EPOLL_TYPE_PING; + ref.flowside = FLOW_SIDX(flow, TGTSIDE); + ref.fd = pingf->sock; + + if (epoll_add(c->epollfd, EPOLLIN, &ref) < 0) { + close(pingf->sock); + goto cancel; + } + flow_dbg(pingf, "new socket %i for echo ID %"PRIu16, pingf->sock, id); flow_hash_insert(c, FLOW_SIDX(pingf, INISIDE)); diff --git a/pif.c b/pif.c index 592fafaab58a..17b41705183c 100644 --- a/pif.c +++ b/pif.c @@ -5,6 +5,7 @@ * Passt/pasta interface types and IDs */ +#include #include #include #include @@ -14,7 +15,7 @@ #include "siphash.h" #include "ip.h" #include "inany.h" -#include "passt.h" +#include "epoll_ctl.h" const char *pif_type_str[] = { [PIF_NONE] = "<none>", @@ -83,7 +84,9 @@ int pif_sock_l4(const struct ctx *c, enum epoll_type type, uint8_t pif, .sa6.sin6_addr = in6addr_any, .sa6.sin6_port = htons(port), }; + union epoll_ref ref; socklen_t sl; + int ret; ASSERT(pif_is_socket(pif)); @@ -93,11 +96,26 @@ int pif_sock_l4(const struct ctx *c, enum epoll_type type, uint8_t pif, ASSERT(addr && inany_is_loopback(addr)); } - if (!addr) - return sock_l4_sa(c, type, &sa, sizeof(sa.sa6), - ifname, false, data); + if (!addr) { + ref.fd = sock_l4_sa(c, type, &sa, sizeof(sa.sa6), + ifname, false); + } else { + pif_sockaddr(c, &sa, &sl, pif, addr, port); + ref.fd = sock_l4_sa(c, type, &sa, sl, + ifname, sa.sa_family == AF_INET6); + } + + if (ref.fd < 0) + return ref.fd; + + ref.type = type; + ref.data = data; + + ret = epoll_add(c->epollfd, EPOLLIN, &ref); + if (ret < 0) { + close(ref.fd); + return ret; + } - pif_sockaddr(c, &sa, &sl, pif, addr, port); - return sock_l4_sa(c, type, &sa, sl, - ifname, sa.sa_family == AF_INET6, data); + return ref.fd; } diff --git a/udp_flow.c b/udp_flow.c index d9c75f1bb1d8..caaf3dababb1 100644 --- a/udp_flow.c +++ b/udp_flow.c @@ -78,16 +78,28 @@ static int udp_flow_sock(const struct ctx *c, flow_sidx_t sidx; uint32_t data; } fref = { .sidx = FLOW_SIDX(uflow, sidei) }; + union epoll_ref ref; + int rc; int s; - s = flowside_sock_l4(c, EPOLL_TYPE_UDP, pif, side, fref.data); + s = flowside_sock_l4(c, EPOLL_TYPE_UDP, pif, side); if (s < 0) { flow_dbg_perror(uflow, "Couldn't open flow specific socket"); return s; } + ref.type = EPOLL_TYPE_UDP; + ref.data = fref.data; + ref.fd = s; + + rc = epoll_add(c->epollfd, EPOLLIN, &ref); + if (rc < 0) { + close(s); + return rc; + } + if (flowside_connect(c, s, pif, side) < 0) { - int rc = -errno; + rc = -errno; epoll_del(c->epollfd, s); close(s); diff --git a/util.c b/util.c index b2490123590a..707ab3388d13 100644 --- a/util.c +++ b/util.c @@ -47,16 +47,14 @@ * @sl: Length of @sa * @ifname: Interface for binding, NULL for any * @v6only: Set IPV6_V6ONLY socket option - * @data: epoll reference portion for protocol handlers * * Return: newly created socket, negative error code on failure */ int sock_l4_sa(const struct ctx *c, enum epoll_type type, const void *sa, socklen_t sl, - const char *ifname, bool v6only, uint32_t data) + const char *ifname, bool v6only) { sa_family_t af = ((const struct sockaddr *)sa)->sa_family; - union epoll_ref ref = { .type = type, .data = data }; bool freebind = false; int fd, y = 1, ret; uint8_t proto; @@ -99,8 +97,6 @@ int sock_l4_sa(const struct ctx *c, enum epoll_type type, return -EBADF; } - ref.fd = fd; - if (v6only) if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &y, sizeof(y))) debug("Failed to set IPV6_V6ONLY on socket %i", fd); @@ -171,10 +167,6 @@ int sock_l4_sa(const struct ctx *c, enum epoll_type type, return ret; } - ret = epoll_add(c->epollfd, EPOLLIN, &ref); - if (ret < 0) - return ret; - return fd; } diff --git a/util.h b/util.h index 8e4b4c5c6032..9108f8f19e14 100644 --- a/util.h +++ b/util.h @@ -207,7 +207,7 @@ struct ctx; int sock_l4_sa(const struct ctx *c, enum epoll_type type, const void *sa, socklen_t sl, - const char *ifname, bool v6only, uint32_t data); + const char *ifname, bool v6only); int sock_unix(char *sock_path); void sock_probe_mem(struct ctx *c); long timespec_diff_ms(const struct timespec *a, const struct timespec *b); -- 2.51.0

The in_epoll boolean flag in tcp_tap_conn and tcp_splice_conn only tracked whether a connection was registered with epoll, not which epoll instance. This limited flexibility for future multi-epoll support. Replace the boolean with a threadnb field in flow_common that identifies which thread (and thus which epoll instance) the flow is registered with. Use FLOW_THREADNB_INVALID to indicate when a flow is not registered with any epoll instance. A threadnb_to_epollfd[] mapping table translates thread numbers to their corresponding epoll file descriptors. Add helper functions: - flow_in_epoll() to check if a flow is registered with epoll - flow_epollfd() to retrieve the epoll fd for a flow's thread - flow_thread_register() to register an epoll fd with a thread - flow_thread_set() to set the thread number of a flow This change also simplifies tcp_timer_ctl() and conn_flag_do() by removing the need to pass the context 'c', since the epoll fd is now directly accessible from the flow structure via flow_epollfd(). Signed-off-by: Laurent Vivier --- flow.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++- flow.h | 12 ++++++++++++ passt.c | 1 + tcp.c | 39 ++++++++++++++++++++------------------ tcp_conn.h | 8 +------- tcp_splice.c | 24 ++++++++++++------------ 6 files changed, 99 insertions(+), 38 deletions(-) diff --git a/flow.c b/flow.c index b14e9d8b63ff..d56bae776239 100644 --- a/flow.c +++ b/flow.c @@ -116,6 +116,7 @@ static_assert(ARRAY_SIZE(flow_proto) == FLOW_NUM_TYPES, unsigned flow_first_free; union flow flowtab[FLOW_MAX]; static const union flow *flow_new_entry; /* = NULL */ +static int threadnb_to_epollfd[FLOW_THREADNB_SIZE]; /* Hash table to index it */ #define FLOW_HASH_LOAD 70 /* % */ @@ -347,6 +348,55 @@ static void flow_set_state(struct flow_common *f, enum flow_state state) flow_log_details_(f, LOG_DEBUG, MAX(state, oldstate)); } +/** + * flow_in_epoll() - Check if flow is registered with an epoll instance + * @f: Flow to check + * + * Return: true if flow is registered with epoll, false otherwise + */ +bool flow_in_epoll(const struct flow_common *f) +{ + return f->threadnb != FLOW_THREADNB_INVALID; +} + +/** + * flow_epollfd() - Get the epoll file descriptor for a flow + * @f: Flow to query + * + * Return: epoll file descriptor associated with the flow's thread + */ +int flow_epollfd(const struct flow_common *f) +{ + ASSERT(f->threadnb < FLOW_THREADNB_MAX); + + return threadnb_to_epollfd[f->threadnb]; +} + +/** + * flow_thread_set() - Associate a flow with a thread + * @f: Flow to update + * @threadnb: Thread number to associate with this flow + */ +void flow_thread_set(struct flow_common *f, int threadnb) +{ + ASSERT(threadnb < FLOW_THREADNB_MAX); + + f->threadnb = threadnb; +} + +/** + * flow_thread_register() - Initialize the threadnb -> epollfd mapping + * @threadnb: Thread number to associate to + * @epollfd: epoll file descriptor for the thread + */ +void flow_thread_register(int threadnb, int epollfd) +{ + ASSERT(threadnb < FLOW_THREADNB_MAX); + ASSERT(epollfd >= 0); + + threadnb_to_epollfd[threadnb] = epollfd; +} + /** * flow_initiate_() - Move flow to INI, setting pif[INISIDE] * @flow: Flow to change state @@ -548,6 +598,7 @@ union flow *flow_alloc(void) flow_new_entry = flow; memset(flow, 0, sizeof(*flow)); + flow->f.threadnb = FLOW_THREADNB_INVALID; flow_set_state(&flow->f, FLOW_STATE_NEW); return flow; @@ -827,7 +878,7 @@ void flow_defer_handler(const struct ctx *c, const struct timespec *now) case FLOW_TCP_SPLICE: closed = tcp_splice_flow_defer(&flow->tcp_splice); if (!closed && timer) - tcp_splice_timer(c, &flow->tcp_splice); + tcp_splice_timer(&flow->tcp_splice); break; case FLOW_PING4: case FLOW_PING6: diff --git a/flow.h b/flow.h index ef138b83add8..700d8b32c990 100644 --- a/flow.h +++ b/flow.h @@ -177,6 +177,8 @@ int flowside_connect(const struct ctx *c, int s, * @type: Type of packet flow * @pif[]: Interface for each side of the flow * @side[]: Information for each side of the flow + * @threadnb: Thread number flow is registered with + * (FLOW_THREADNB_INVALID if not) */ struct flow_common { #ifdef __GNUC__ @@ -192,8 +194,14 @@ struct flow_common { #endif uint8_t pif[SIDES]; struct flowside side[SIDES]; +#define FLOW_THREADNB_BITS 8 + unsigned int threadnb:FLOW_THREADNB_BITS; }; +#define FLOW_THREADNB_SIZE (1 << FLOW_THREADNB_BITS) +#define FLOW_THREADNB_MAX (FLOW_THREADNB_SIZE - 1) +#define FLOW_THREADNB_INVALID FLOW_THREADNB_MAX + #define FLOW_INDEX_BITS 17 /* 128k - 1 */ #define FLOW_MAX MAX_FROM_BITS(FLOW_INDEX_BITS) @@ -249,6 +257,10 @@ flow_sidx_t flow_lookup_sa(const struct ctx *c, uint8_t proto, uint8_t pif, union flow; void flow_init(void); +bool flow_in_epoll(const struct flow_common *f); +int flow_epollfd(const struct flow_common *f); +void flow_thread_set(struct flow_common *f, int threadnb); +void flow_thread_register(int threadnb, int epollfd); void flow_defer_handler(const struct ctx *c, const struct timespec *now); int flow_migrate_source_early(struct ctx *c, const struct migrate_stage *stage, int fd); diff --git a/passt.c b/passt.c index af928111786b..37f2c897be84 100644 --- a/passt.c +++ b/passt.c @@ -285,6 +285,7 @@ int main(int argc, char **argv) c.epollfd = epoll_create1(EPOLL_CLOEXEC); if (c.epollfd == -1) die_perror("Failed to create epoll file descriptor"); + flow_thread_register(0, c.epollfd); if (getrlimit(RLIMIT_NOFILE, &limit)) die_perror("Failed to get maximum value of open files limit"); diff --git a/tcp.c b/tcp.c index db9f17c0622f..8c49852b8454 100644 --- a/tcp.c +++ b/tcp.c @@ -504,25 +504,27 @@ static uint32_t tcp_conn_epoll_events(uint8_t events, uint8_t conn_flags) */ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn) { - int m = conn->in_epoll ? EPOLL_CTL_MOD : EPOLL_CTL_ADD; + int m = flow_in_epoll(&conn->f) ? EPOLL_CTL_MOD : EPOLL_CTL_ADD; union epoll_ref ref = { .type = EPOLL_TYPE_TCP, .fd = conn->sock, .flowside = FLOW_SIDX(conn, !TAPSIDE(conn)), }; struct epoll_event ev = { .data.u64 = ref.u64 }; + int epollfd = flow_in_epoll(&conn->f) ? flow_epollfd(&conn->f) + : c->epollfd; if (conn->events == CLOSED) { - if (conn->in_epoll) - epoll_del(c->epollfd, conn->sock); + if (flow_in_epoll(&conn->f)) + epoll_del(epollfd, conn->sock); if (conn->timer != -1) - epoll_del(c->epollfd, conn->timer); + epoll_del(epollfd, conn->timer); return 0; } ev.events = tcp_conn_epoll_events(conn->events, conn->flags); - if (epoll_ctl(c->epollfd, m, conn->sock, &ev)) + if (epoll_ctl(epollfd, m, conn->sock, &ev)) return -errno; - conn->in_epoll = true; + flow_thread_set(&conn->f, 0); if (conn->timer != -1) { union epoll_ref ref_t = { .type = EPOLL_TYPE_TCP_TIMER, @@ -531,7 +533,8 @@ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn) struct epoll_event ev_t = { .data.u64 = ref_t.u64, .events = EPOLLIN | EPOLLET }; - if (epoll_ctl(c->epollfd, EPOLL_CTL_MOD, conn->timer, &ev_t)) + if (epoll_ctl(flow_epollfd(&conn->f), EPOLL_CTL_MOD, + conn->timer, &ev_t)) return -errno; } @@ -540,12 +543,11 @@ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn) /** * tcp_timer_ctl() - Set timerfd based on flags/events, create timerfd if needed - * @c: Execution context * @conn: Connection pointer * * #syscalls timerfd_create timerfd_settime */ -static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn) +static void tcp_timer_ctl(struct tcp_tap_conn *conn) { struct itimerspec it = { { 0 }, { 0 } }; @@ -570,7 +572,8 @@ static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn) } conn->timer = fd; - if (epoll_ctl(c->epollfd, EPOLL_CTL_ADD, conn->timer, &ev)) { + if (epoll_ctl(flow_epollfd(&conn->f), EPOLL_CTL_ADD, + conn->timer, &ev)) { flow_dbg_perror(conn, "failed to add timer"); close(conn->timer); conn->timer = -1; @@ -628,7 +631,7 @@ void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn, * flags and factor this into the logic below. */ if (flag == ACK_FROM_TAP_DUE) - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); return; } @@ -644,7 +647,7 @@ void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn, if (flag == ACK_FROM_TAP_DUE || flag == ACK_TO_TAP_DUE || (flag == ~ACK_FROM_TAP_DUE && (conn->flags & ACK_TO_TAP_DUE)) || (flag == ~ACK_TO_TAP_DUE && (conn->flags & ACK_FROM_TAP_DUE))) - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); } /** @@ -699,7 +702,7 @@ void conn_event_do(const struct ctx *c, struct tcp_tap_conn *conn, tcp_epoll_ctl(c, conn); if (CONN_HAS(conn, SOCK_FIN_SENT | TAP_FIN_ACKED)) - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); } /** @@ -1757,7 +1760,7 @@ static int tcp_data_from_tap(const struct ctx *c, struct tcp_tap_conn *conn, seq, conn->seq_from_tap); tcp_send_flag(c, conn, ACK); - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); if (p->count == 1) { tcp_tap_window_update(c, conn, @@ -2406,7 +2409,7 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref) if (conn->flags & ACK_TO_TAP_DUE) { tcp_send_flag(c, conn, ACK_IF_NEEDED); - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); } else if (conn->flags & ACK_FROM_TAP_DUE) { if (!(conn->events & ESTABLISHED)) { flow_dbg(conn, "handshake timeout"); @@ -2428,7 +2431,7 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref) return; tcp_data_from_sock(c, conn); - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); } } else { struct itimerspec new = { { 0 }, { ACT_TIMEOUT, 0 } }; @@ -3476,7 +3479,7 @@ int tcp_flow_migrate_source_ext(const struct ctx *c, if (c->migrate_no_linger) close(s); else - epoll_del(c->epollfd, s); + epoll_del(flow_epollfd(&conn->f), s); /* Adjustments unrelated to FIN segments: sequence numbers we dumped are * based on the end of the queues. @@ -3625,7 +3628,7 @@ static int tcp_flow_repair_connect(const struct ctx *c, return rc; } - conn->in_epoll = 0; + conn->f.threadnb = FLOW_THREADNB_INVALID; conn->timer = -1; conn->listening_sock = -1; diff --git a/tcp_conn.h b/tcp_conn.h index 38b5c541f003..81333122d531 100644 --- a/tcp_conn.h +++ b/tcp_conn.h @@ -12,7 +12,6 @@ /** * struct tcp_tap_conn - Descriptor for a TCP connection (not spliced) * @f: Generic flow information - * @in_epoll: Is the connection in the epoll set? * @retrans: Number of retransmissions occurred due to ACK_TIMEOUT * @ws_from_tap: Window scaling factor advertised from tap/guest * @ws_to_tap: Window scaling factor advertised to tap/guest @@ -36,8 +35,6 @@ struct tcp_tap_conn { /* Must be first element */ struct flow_common f; - bool in_epoll :1; - #define TCP_RETRANS_BITS 3 unsigned int retrans :TCP_RETRANS_BITS; #define TCP_MAX_RETRANS MAX_FROM_BITS(TCP_RETRANS_BITS) @@ -196,7 +193,6 @@ struct tcp_tap_transfer_ext { * @written: Bytes written (not fully written from one other side read) * @events: Events observed/actions performed on connection * @flags: Connection flags (attributes, not events) - * @in_epoll: Is the connection in the epoll set? */ struct tcp_splice_conn { /* Must be first element */ @@ -220,8 +216,6 @@ struct tcp_splice_conn { #define RCVLOWAT_SET(sidei_) ((sidei_) ? BIT(1) : BIT(0)) #define RCVLOWAT_ACT(sidei_) ((sidei_) ? BIT(3) : BIT(2)) #define CLOSING BIT(4) - - bool in_epoll :1; }; /* Socket pools */ @@ -245,7 +239,7 @@ int tcp_flow_migrate_target_ext(struct ctx *c, struct tcp_tap_conn *conn, int fd bool tcp_flow_is_established(const struct tcp_tap_conn *conn); bool tcp_splice_flow_defer(struct tcp_splice_conn *conn); -void tcp_splice_timer(const struct ctx *c, struct tcp_splice_conn *conn); +void tcp_splice_timer(struct tcp_splice_conn *conn); int tcp_conn_pool_sock(int pool[]); int tcp_conn_sock(sa_family_t af); int tcp_sock_refill_pool(int pool[], sa_family_t af); diff --git a/tcp_splice.c b/tcp_splice.c index 6f21184bdc55..703bd7610890 100644 --- a/tcp_splice.c +++ b/tcp_splice.c @@ -149,7 +149,9 @@ static void tcp_splice_conn_epoll_events(uint16_t events, static int tcp_splice_epoll_ctl(const struct ctx *c, struct tcp_splice_conn *conn) { - int m = conn->in_epoll ? EPOLL_CTL_MOD : EPOLL_CTL_ADD; + int epollfd = flow_in_epoll(&conn->f) ? flow_epollfd(&conn->f) + : c->epollfd; + int m = flow_in_epoll(&conn->f) ? EPOLL_CTL_MOD : EPOLL_CTL_ADD; const union epoll_ref ref[SIDES] = { { .type = EPOLL_TYPE_TCP_SPLICE, .fd = conn->s[0], .flowside = FLOW_SIDX(conn, 0) }, @@ -161,25 +163,24 @@ static int tcp_splice_epoll_ctl(const struct ctx *c, tcp_splice_conn_epoll_events(conn->events, ev); - if (epoll_ctl(c->epollfd, m, conn->s[0], &ev[0]) || - epoll_ctl(c->epollfd, m, conn->s[1], &ev[1])) { + + if (epoll_ctl(epollfd, m, conn->s[0], &ev[0]) || + epoll_ctl(epollfd, m, conn->s[1], &ev[1])) { int ret = -errno; flow_perror(conn, "ERROR on epoll_ctl()"); return ret; } - - conn->in_epoll = true; + flow_thread_set(&conn->f, 0); return 0; } /** * conn_flag_do() - Set/unset given flag, log, update epoll on CLOSING flag - * @c: Execution context * @conn: Connection pointer * @flag: Flag to set, or ~flag to unset */ -static void conn_flag_do(const struct ctx *c, struct tcp_splice_conn *conn, +static void conn_flag_do(struct tcp_splice_conn *conn, unsigned long flag) { if (flag & (flag - 1)) { @@ -204,15 +205,15 @@ static void conn_flag_do(const struct ctx *c, struct tcp_splice_conn *conn, } if (flag == CLOSING) { - epoll_del(c->epollfd, conn->s[0]); - epoll_del(c->epollfd, conn->s[1]); + epoll_del(flow_epollfd(&conn->f), conn->s[0]); + epoll_del(flow_epollfd(&conn->f), conn->s[1]); } } #define conn_flag(c, conn, flag) \ do { \ flow_trace(conn, "flag at %s:%i", __func__, __LINE__); \ - conn_flag_do(c, conn, flag); \ + conn_flag_do(conn, flag); \ } while (0) /** @@ -751,10 +752,9 @@ void tcp_splice_init(struct ctx *c) /** * tcp_splice_timer() - Timer for spliced connections - * @c: Execution context * @conn: Connection to handle */ -void tcp_splice_timer(const struct ctx *c, struct tcp_splice_conn *conn) +void tcp_splice_timer(struct tcp_splice_conn *conn) { unsigned sidei; -- 2.51.0

Extract the epoll event processing logic from main() into a separate passt_worker() function. This refactoring prepares the code for future threading support where passt_worker() will be called as a worker thread callback. The new function handles: - Processing epoll events and dispatching to protocol handlers - Event statistics tracking and printing - Post-handler periodic tasks (timers, deferred work) - Migration handling No functional changes, purely a code restructuring. Signed-off-by: Laurent Vivier --- passt.c | 160 +++++++++++++++++++++++++++++++------------------------- 1 file changed, 88 insertions(+), 72 deletions(-) diff --git a/passt.c b/passt.c index 37f2c897be84..5bfa4c6353d9 100644 --- a/passt.c +++ b/passt.c @@ -229,6 +229,92 @@ static void print_stats(const struct ctx *c, const struct passt_stats *stats, lines_printed++; } +/** + * passt_worker() - Process epoll events and handle protocol operations + * @opaque: Pointer to execution context (struct ctx) + * @nfds: Number of file descriptors ready (epoll_wait return value) + * @events: epoll_event array of ready file descriptors + */ +static void passt_worker(void *opaque, int nfds, struct epoll_event *events) +{ + static struct passt_stats stats = { 0 }; + struct ctx *c = opaque; + struct timespec now; + int i; + + if (clock_gettime(CLOCK_MONOTONIC, &now)) + err_perror("Failed to get CLOCK_MONOTONIC time"); + + for (i = 0; i < nfds; i++) { + union epoll_ref ref = *((union epoll_ref *)&events[i].data.u64); + uint32_t eventmask = events[i].events; + + trace("%s: epoll event on %s %i (events: 0x%08x)", + c->mode == MODE_PASTA ? "pasta" : "passt", + EPOLL_TYPE_STR(ref.type), ref.fd, eventmask); + + switch (ref.type) { + case EPOLL_TYPE_TAP_PASTA: + tap_handler_pasta(c, eventmask, &now); + break; + case EPOLL_TYPE_TAP_PASST: + tap_handler_passt(c, eventmask, &now); + break; + case EPOLL_TYPE_TAP_LISTEN: + tap_listen_handler(c, eventmask); + break; + case EPOLL_TYPE_NSQUIT_INOTIFY: + pasta_netns_quit_inotify_handler(c, ref.fd); + break; + case EPOLL_TYPE_NSQUIT_TIMER: + pasta_netns_quit_timer_handler(c, ref); + break; + case EPOLL_TYPE_TCP: + tcp_sock_handler(c, ref, eventmask); + break; + case EPOLL_TYPE_TCP_SPLICE: + tcp_splice_sock_handler(c, ref, eventmask); + break; + case EPOLL_TYPE_TCP_LISTEN: + tcp_listen_handler(c, ref, &now); + break; + case EPOLL_TYPE_TCP_TIMER: + tcp_timer_handler(c, ref); + break; + case EPOLL_TYPE_UDP_LISTEN: + udp_listen_sock_handler(c, ref, eventmask, &now); + break; + case EPOLL_TYPE_UDP: + udp_sock_handler(c, ref, eventmask, &now); + break; + case EPOLL_TYPE_PING: + icmp_sock_handler(c, ref); + break; + case EPOLL_TYPE_VHOST_CMD: + vu_control_handler(c->vdev, c->fd_tap, eventmask); + break; + case EPOLL_TYPE_VHOST_KICK: + vu_kick_cb(c->vdev, ref, &now); + break; + case EPOLL_TYPE_REPAIR_LISTEN: + repair_listen_handler(c, eventmask); + break; + case EPOLL_TYPE_REPAIR: + repair_handler(c, eventmask); + break; + default: + /* Can't happen */ + ASSERT(0); + } + stats.events[ref.type]++; + print_stats(c, &stats, &now); + } + + post_handler(c, &now); + + migrate_handler(c); +} + /** * main() - Entry point and main loop * @argc: Argument count @@ -246,8 +332,7 @@ static void print_stats(const struct ctx *c, const struct passt_stats *stats, int main(int argc, char **argv) { struct epoll_event events[NUM_EPOLL_EVENTS]; - struct passt_stats stats = { 0 }; - int nfds, i, devnull_fd = -1; + int nfds, devnull_fd = -1; struct ctx c = { 0 }; struct rlimit limit; struct timespec now; @@ -355,77 +440,8 @@ loop: if (nfds == -1 && errno != EINTR) die_perror("epoll_wait() failed in main loop"); - if (clock_gettime(CLOCK_MONOTONIC, &now)) - err_perror("Failed to get CLOCK_MONOTONIC time"); - - for (i = 0; i < nfds; i++) { - union epoll_ref ref = *((union epoll_ref *)&events[i].data.u64); - uint32_t eventmask = events[i].events; - - trace("%s: epoll event on %s %i (events: 0x%08x)", - c.mode == MODE_PASTA ? "pasta" : "passt", - EPOLL_TYPE_STR(ref.type), ref.fd, eventmask); - - switch (ref.type) { - case EPOLL_TYPE_TAP_PASTA: - tap_handler_pasta(&c, eventmask, &now); - break; - case EPOLL_TYPE_TAP_PASST: - tap_handler_passt(&c, eventmask, &now); - break; - case EPOLL_TYPE_TAP_LISTEN: - tap_listen_handler(&c, eventmask); - break; - case EPOLL_TYPE_NSQUIT_INOTIFY: - pasta_netns_quit_inotify_handler(&c, ref.fd); - break; - case EPOLL_TYPE_NSQUIT_TIMER: - pasta_netns_quit_timer_handler(&c, ref); - break; - case EPOLL_TYPE_TCP: - tcp_sock_handler(&c, ref, eventmask); - break; - case EPOLL_TYPE_TCP_SPLICE: - tcp_splice_sock_handler(&c, ref, eventmask); - break; - case EPOLL_TYPE_TCP_LISTEN: - tcp_listen_handler(&c, ref, &now); - break; - case EPOLL_TYPE_TCP_TIMER: - tcp_timer_handler(&c, ref); - break; - case EPOLL_TYPE_UDP_LISTEN: - udp_listen_sock_handler(&c, ref, eventmask, &now); - break; - case EPOLL_TYPE_UDP: - udp_sock_handler(&c, ref, eventmask, &now); - break; - case EPOLL_TYPE_PING: - icmp_sock_handler(&c, ref); - break; - case EPOLL_TYPE_VHOST_CMD: - vu_control_handler(c.vdev, c.fd_tap, eventmask); - break; - case EPOLL_TYPE_VHOST_KICK: - vu_kick_cb(c.vdev, ref, &now); - break; - case EPOLL_TYPE_REPAIR_LISTEN: - repair_listen_handler(&c, eventmask); - break; - case EPOLL_TYPE_REPAIR: - repair_handler(&c, eventmask); - break; - default: - /* Can't happen */ - ASSERT(0); - } - stats.events[ref.type]++; - print_stats(&c, &stats, &now); - } - - post_handler(&c, &now); - migrate_handler(&c); + passt_worker(&c, nfds, events); goto loop; } -- 2.51.0

On 17/10/2025 13:48, Stefano Brivio wrote:

I was reviewing v3 but I can seamlessly move on to v4, just two things here:

On Fri, 17 Oct 2025 12:31:24 +0200 Laurent Vivier wrote:

...

Centralize epoll_add() and epoll_del() helper functions into new epoll_ctl.c/h files.

This also moves the union epoll_ref definition from passt.h to epoll_ctl.h where it's more logically placed.

The new epoll_add() helper simplifies adding file descriptors to epoll by taking an epoll_ref and events, handling error reporting consistently across all call sites.

Signed-off-by: Laurent Vivier --- Makefile | 22 +++++++++++----------- epoll_ctl.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ epoll_ctl.h | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++ icmp.c | 4 +--- passt.c | 2 +- passt.h | 34 ---------------------------------- pasta.c | 7 +++---- repair.c | 14 +++++--------- tap.c | 13 ++++--------- tcp.c | 2 +- tcp_splice.c | 2 +- udp.c | 2 +- udp_flow.c | 1 + util.c | 22 +++------------------- util.h | 4 +++- vhost_user.c | 8 ++------ vu_common.c | 2 +- 17 files changed, 134 insertions(+), 101 deletions(-) create mode 100644 epoll_ctl.c create mode 100644 epoll_ctl.h

diff --git a/Makefile b/Makefile index 3328f8324140..91e037b8fd3c 100644 --- a/Makefile +++ b/Makefile @@ -37,23 +37,23 @@ FLAGS += -DPAGE_SIZE=$(shell getconf PAGE_SIZE) FLAGS += -DVERSION=\"$(VERSION)\" FLAGS += -DDUAL_STACK_SOCKETS=$(DUAL_STACK_SOCKETS)

-PASST_SRCS = arch.c arp.c checksum.c conf.c dhcp.c dhcpv6.c flow.c fwd.c \ - icmp.c igmp.c inany.c iov.c ip.c isolation.c lineread.c log.c mld.c \ - ndp.c netlink.c migrate.c packet.c passt.c pasta.c pcap.c pif.c \ - repair.c tap.c tcp.c tcp_buf.c tcp_splice.c tcp_vu.c udp.c udp_flow.c \ - udp_vu.c util.c vhost_user.c virtio.c vu_common.c +PASST_SRCS = arch.c arp.c checksum.c conf.c dhcp.c dhcpv6.c epoll_ctl.c \ + flow.c fwd.c icmp.c igmp.c inany.c iov.c ip.c isolation.c lineread.c \ + log.c mld.c ndp.c netlink.c migrate.c packet.c passt.c pasta.c pcap.c \ + pif.c repair.c tap.c tcp.c tcp_buf.c tcp_splice.c tcp_vu.c udp.c \ + udp_flow.c udp_vu.c util.c vhost_user.c virtio.c vu_common.c QRAP_SRCS = qrap.c PASST_REPAIR_SRCS = passt-repair.c SRCS = $(PASST_SRCS) $(QRAP_SRCS) $(PASST_REPAIR_SRCS)

MANPAGES = passt.1 pasta.1 qrap.1 passt-repair.1

-PASST_HEADERS = arch.h arp.h checksum.h conf.h dhcp.h dhcpv6.h flow.h fwd.h \ - flow_table.h icmp.h icmp_flow.h inany.h iov.h ip.h isolation.h \ - lineread.h log.h migrate.h ndp.h netlink.h packet.h passt.h pasta.h \ - pcap.h pif.h repair.h siphash.h tap.h tcp.h tcp_buf.h tcp_conn.h \ - tcp_internal.h tcp_splice.h tcp_vu.h udp.h udp_flow.h udp_internal.h \ - udp_vu.h util.h vhost_user.h virtio.h vu_common.h +PASST_HEADERS = arch.h arp.h checksum.h conf.h dhcp.h dhcpv6.h epoll_ctl.h \ + flow.h fwd.h flow_table.h icmp.h icmp_flow.h inany.h iov.h ip.h \ + isolation.h lineread.h log.h migrate.h ndp.h netlink.h packet.h \ + passt.h pasta.h pcap.h pif.h repair.h siphash.h tap.h tcp.h tcp_buf.h \ + tcp_conn.h tcp_internal.h tcp_splice.h tcp_vu.h udp.h udp_flow.h \ + udp_internal.h udp_vu.h util.h vhost_user.h virtio.h vu_common.h HEADERS = $(PASST_HEADERS) seccomp.h

C := \#include \nint main(){int a=getrandom(0, 0, 0);} diff --git a/epoll_ctl.c b/epoll_ctl.c new file mode 100644 index 000000000000..7a520560aeb9 --- /dev/null +++ b/epoll_ctl.c @@ -0,0 +1,45 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* epoll_ctl.c - epoll manipulation helpers + * + * Copyright Red Hat + * Author: Laurent Vivier + */ + +#include + +#include "epoll_ctl.h" + +/** + * epoll_add() - Add a file descriptor to an epollfd + * @epollfd: epoll file descriptor to add to + * @events: epoll events + * @ref: epoll reference for the file descriptor (includes fd and metadata) + * + * Return: 0 on success, negative errno on failure + */ +int epoll_add(int epollfd, uint32_t events, union epoll_ref *ref) +{ + struct epoll_event ev; + int ret; + + ev.events = events; + ev.data.u64 = ref->u64; + + ret = epoll_ctl(epollfd, EPOLL_CTL_ADD, ref->fd, &ev); + if (ret == -1) { + ret = -errno; + err("Failed to add fd to epoll: %s", strerror_(-ret)); + } + + return ret; +} + +/** + * epoll_del() - Remove a file descriptor from an epollfd + * @epollfd: epoll file descriptor to remove from + * @fd: File descriptor to remove + */ +void epoll_del(int epollfd, int fd) +{ + epoll_ctl(epollfd, EPOLL_CTL_DEL, fd, NULL); +} diff --git a/epoll_ctl.h b/epoll_ctl.h new file mode 100644 index 000000000000..cf92b0f63f26 --- /dev/null +++ b/epoll_ctl.h @@ -0,0 +1,51 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later + * Copyright Red Hat + * Author: Laurent Vivier + */ + +#ifndef EPOLL_CTL_H +#define EPOLL_CTL_H + +#include + +#include "util.h" +#include "passt.h" +#include "epoll_type.h" +#include "flow.h" +#include "tcp.h" +#include "udp.h" + +/** + * union epoll_ref - Breakdown of reference for epoll fd bookkeeping + * @type: Type of fd (tells us what to do with events) + * @fd: File descriptor number (implies < 2^24 total descriptors) + * @flow: Index of the flow this fd is linked to + * @tcp_listen: TCP-specific reference part for listening sockets + * @udp: UDP-specific reference part + * @data: Data handled by protocol handlers + * @nsdir_fd: netns dirfd for fallback timer checking if namespace is gone + * @queue: vhost-user queue index for this fd + * @u64: Opaque reference for epoll_ctl() and epoll_wait() + */ +union epoll_ref { + struct { + enum epoll_type type:8; + int32_t fd:FD_REF_BITS;

Same comment as for v3, quoting:

--- Do the definitions of FD_REF_BITS and FD_REF_MAX really belong to util.h? It would be clearer to have them here. I didn't check all the possible places where you would need to include this header though. ---

I didn't move them from util.h because it's not only used by epoll but also by tcp_tap_conn. So for me it was a generic definition and that fits with util.h. But I can move it if you prefer. Thanks, Laurent

Nits only: On Fri, 17 Oct 2025 12:31:26 +0200 Laurent Vivier wrote:

The in_epoll boolean flag in tcp_tap_conn and tcp_splice_conn only tracked whether a connection was registered with epoll, not which epoll instance. This limited flexibility for future multi-epoll support.

Replace the boolean with a threadnb field in flow_common that identifies which thread (and thus which epoll instance) the flow is registered with. Use FLOW_THREADNB_INVALID to indicate when a flow is not registered with any epoll instance. A threadnb_to_epollfd[] mapping table translates thread numbers to their corresponding epoll file descriptors.

It wasn't really clear to me until I actually started digging into this change what NB meant there. For me it's "notifier block" before "number", but that didn't make sense either. Some ideas (even though maybe as David suggested this name shouldn't have "thread" in it at all): - f->thread / FLOW_THREAD_INVALID - f->thread_id / FLOW_THREAD_ID_INVALID ...or f->epoll_id, reflecting David's observation?

Add helper functions: - flow_in_epoll() to check if a flow is registered with epoll - flow_epollfd() to retrieve the epoll fd for a flow's thread - flow_thread_register() to register an epoll fd with a thread - flow_thread_set() to set the thread number of a flow

This change also simplifies tcp_timer_ctl() and conn_flag_do() by removing the need to pass the context 'c', since the epoll fd is now directly accessible from the flow structure via flow_epollfd().

Signed-off-by: Laurent Vivier --- flow.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++- flow.h | 12 ++++++++++++ passt.c | 1 + tcp.c | 39 ++++++++++++++++++++------------------ tcp_conn.h | 8 +------- tcp_splice.c | 24 ++++++++++++------------ 6 files changed, 99 insertions(+), 38 deletions(-)

diff --git a/flow.c b/flow.c index b14e9d8b63ff..d56bae776239 100644 --- a/flow.c +++ b/flow.c @@ -116,6 +116,7 @@ static_assert(ARRAY_SIZE(flow_proto) == FLOW_NUM_TYPES, unsigned flow_first_free; union flow flowtab[FLOW_MAX]; static const union flow *flow_new_entry; /* = NULL */

It would be nice to have an idea of how this table is organised without looking at how it's used, say: /* Table of epoll file descriptors, indexed by thread number */ ...or indexed by "epoll identifiers", perhaps, if we want to drop references to threads here.

+static int threadnb_to_epollfd[FLOW_THREADNB_SIZE];

/* Hash table to index it */ #define FLOW_HASH_LOAD 70 /* % */ @@ -347,6 +348,55 @@ static void flow_set_state(struct flow_common *f, enum flow_state state) flow_log_details_(f, LOG_DEBUG, MAX(state, oldstate)); }

+/** + * flow_in_epoll() - Check if flow is registered with an epoll instance + * @f: Flow to check + * + * Return: true if flow is registered with epoll, false otherwise + */ +bool flow_in_epoll(const struct flow_common *f) +{ + return f->threadnb != FLOW_THREADNB_INVALID; +} + +/** + * flow_epollfd() - Get the epoll file descriptor for a flow + * @f: Flow to query + * + * Return: epoll file descriptor associated with the flow's thread + */ +int flow_epollfd(const struct flow_common *f) +{ + ASSERT(f->threadnb < FLOW_THREADNB_MAX); + + return threadnb_to_epollfd[f->threadnb]; +} + +/** + * flow_thread_set() - Associate a flow with a thread + * @f: Flow to update + * @threadnb: Thread number to associate with this flow + */ +void flow_thread_set(struct flow_common *f, int threadnb) +{ + ASSERT(threadnb < FLOW_THREADNB_MAX); + + f->threadnb = threadnb; +} + +/** + * flow_thread_register() - Initialize the threadnb -> epollfd mapping + * @threadnb: Thread number to associate to + * @epollfd: epoll file descriptor for the thread + */ +void flow_thread_register(int threadnb, int epollfd) +{ + ASSERT(threadnb < FLOW_THREADNB_MAX); + ASSERT(epollfd >= 0); + + threadnb_to_epollfd[threadnb] = epollfd; +} + /** * flow_initiate_() - Move flow to INI, setting pif[INISIDE] * @flow: Flow to change state @@ -548,6 +598,7 @@ union flow *flow_alloc(void)

flow_new_entry = flow; memset(flow, 0, sizeof(*flow)); + flow->f.threadnb = FLOW_THREADNB_INVALID; flow_set_state(&flow->f, FLOW_STATE_NEW);

return flow; @@ -827,7 +878,7 @@ void flow_defer_handler(const struct ctx *c, const struct timespec *now) case FLOW_TCP_SPLICE: closed = tcp_splice_flow_defer(&flow->tcp_splice); if (!closed && timer) - tcp_splice_timer(c, &flow->tcp_splice); + tcp_splice_timer(&flow->tcp_splice); break; case FLOW_PING4: case FLOW_PING6: diff --git a/flow.h b/flow.h index ef138b83add8..700d8b32c990 100644 --- a/flow.h +++ b/flow.h @@ -177,6 +177,8 @@ int flowside_connect(const struct ctx *c, int s, * @type: Type of packet flow * @pif[]: Interface for each side of the flow * @side[]: Information for each side of the flow + * @threadnb: Thread number flow is registered with + * (FLOW_THREADNB_INVALID if not)

You could phrase this more directly, say, "thread identifier, or FLOW_THREAD_INVALID", or "epollfd identifier, or EPOLLFD_ID_INVALID". This is a structure describing flows, it's not surprising it's about the flow.

*/ struct flow_common { #ifdef __GNUC__ @@ -192,8 +194,14 @@ struct flow_common { #endif uint8_t pif[SIDES]; struct flowside side[SIDES]; +#define FLOW_THREADNB_BITS 8 + unsigned int threadnb:FLOW_THREADNB_BITS; };

+#define FLOW_THREADNB_SIZE (1 << FLOW_THREADNB_BITS) +#define FLOW_THREADNB_MAX (FLOW_THREADNB_SIZE - 1) +#define FLOW_THREADNB_INVALID FLOW_THREADNB_MAX + #define FLOW_INDEX_BITS 17 /* 128k - 1 */ #define FLOW_MAX MAX_FROM_BITS(FLOW_INDEX_BITS)

@@ -249,6 +257,10 @@ flow_sidx_t flow_lookup_sa(const struct ctx *c, uint8_t proto, uint8_t pif, union flow;

void flow_init(void); +bool flow_in_epoll(const struct flow_common *f); +int flow_epollfd(const struct flow_common *f); +void flow_thread_set(struct flow_common *f, int threadnb); +void flow_thread_register(int threadnb, int epollfd); void flow_defer_handler(const struct ctx *c, const struct timespec *now); int flow_migrate_source_early(struct ctx *c, const struct migrate_stage *stage, int fd); diff --git a/passt.c b/passt.c index af928111786b..37f2c897be84 100644 --- a/passt.c +++ b/passt.c @@ -285,6 +285,7 @@ int main(int argc, char **argv) c.epollfd = epoll_create1(EPOLL_CLOEXEC); if (c.epollfd == -1) die_perror("Failed to create epoll file descriptor"); + flow_thread_register(0, c.epollfd);

Temporary, I suppose. If not, maybe it deserves its own constant, such as EPOLLFD_ID_DEFAULT?

if (getrlimit(RLIMIT_NOFILE, &limit)) die_perror("Failed to get maximum value of open files limit"); diff --git a/tcp.c b/tcp.c index db9f17c0622f..8c49852b8454 100644 --- a/tcp.c +++ b/tcp.c @@ -504,25 +504,27 @@ static uint32_t tcp_conn_epoll_events(uint8_t events, uint8_t conn_flags) */ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn) { - int m = conn->in_epoll ? EPOLL_CTL_MOD : EPOLL_CTL_ADD; + int m = flow_in_epoll(&conn->f) ? EPOLL_CTL_MOD : EPOLL_CTL_ADD; union epoll_ref ref = { .type = EPOLL_TYPE_TCP, .fd = conn->sock, .flowside = FLOW_SIDX(conn, !TAPSIDE(conn)), }; struct epoll_event ev = { .data.u64 = ref.u64 }; + int epollfd = flow_in_epoll(&conn->f) ? flow_epollfd(&conn->f) + : c->epollfd;

We usually align the second expression to the ternary operator, see also example in sock_l4_sa(), say: int epollfd = flow_in_epoll(&conn->f) ? flow_epollfd(&conn->f) : c->epollfd;

if (conn->events == CLOSED) { - if (conn->in_epoll) - epoll_del(c->epollfd, conn->sock); + if (flow_in_epoll(&conn->f)) + epoll_del(epollfd, conn->sock); if (conn->timer != -1) - epoll_del(c->epollfd, conn->timer); + epoll_del(epollfd, conn->timer); return 0; }

ev.events = tcp_conn_epoll_events(conn->events, conn->flags);

- if (epoll_ctl(c->epollfd, m, conn->sock, &ev)) + if (epoll_ctl(epollfd, m, conn->sock, &ev)) return -errno;

- conn->in_epoll = true; + flow_thread_set(&conn->f, 0);

Not temporary I guess, maybe it's an EPOLLFD_ID_DEFAULT?

if (conn->timer != -1) { union epoll_ref ref_t = { .type = EPOLL_TYPE_TCP_TIMER, @@ -531,7 +533,8 @@ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn) struct epoll_event ev_t = { .data.u64 = ref_t.u64, .events = EPOLLIN | EPOLLET };

- if (epoll_ctl(c->epollfd, EPOLL_CTL_MOD, conn->timer, &ev_t)) + if (epoll_ctl(flow_epollfd(&conn->f), EPOLL_CTL_MOD, + conn->timer, &ev_t)) return -errno; }

@@ -540,12 +543,11 @@ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn)

/** * tcp_timer_ctl() - Set timerfd based on flags/events, create timerfd if needed - * @c: Execution context * @conn: Connection pointer * * #syscalls timerfd_create timerfd_settime */ -static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn) +static void tcp_timer_ctl(struct tcp_tap_conn *conn) { struct itimerspec it = { { 0 }, { 0 } };

@@ -570,7 +572,8 @@ static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn) } conn->timer = fd;

- if (epoll_ctl(c->epollfd, EPOLL_CTL_ADD, conn->timer, &ev)) { + if (epoll_ctl(flow_epollfd(&conn->f), EPOLL_CTL_ADD,

I wouldn't find it outrageous if you assigned an epollfd local variable first so that this doesn't need two lines.

+ conn->timer, &ev)) { flow_dbg_perror(conn, "failed to add timer"); close(conn->timer); conn->timer = -1; @@ -628,7 +631,7 @@ void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn, * flags and factor this into the logic below. */ if (flag == ACK_FROM_TAP_DUE) - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn);

return; } @@ -644,7 +647,7 @@ void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn, if (flag == ACK_FROM_TAP_DUE || flag == ACK_TO_TAP_DUE || (flag == ~ACK_FROM_TAP_DUE && (conn->flags & ACK_TO_TAP_DUE)) || (flag == ~ACK_TO_TAP_DUE && (conn->flags & ACK_FROM_TAP_DUE))) - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); }

/** @@ -699,7 +702,7 @@ void conn_event_do(const struct ctx *c, struct tcp_tap_conn *conn, tcp_epoll_ctl(c, conn);

if (CONN_HAS(conn, SOCK_FIN_SENT | TAP_FIN_ACKED)) - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); }

/** @@ -1757,7 +1760,7 @@ static int tcp_data_from_tap(const struct ctx *c, struct tcp_tap_conn *conn, seq, conn->seq_from_tap);

tcp_send_flag(c, conn, ACK); - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn);

if (p->count == 1) { tcp_tap_window_update(c, conn, @@ -2406,7 +2409,7 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref)

if (conn->flags & ACK_TO_TAP_DUE) { tcp_send_flag(c, conn, ACK_IF_NEEDED); - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); } else if (conn->flags & ACK_FROM_TAP_DUE) { if (!(conn->events & ESTABLISHED)) { flow_dbg(conn, "handshake timeout"); @@ -2428,7 +2431,7 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref) return;

tcp_data_from_sock(c, conn); - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); } } else { struct itimerspec new = { { 0 }, { ACT_TIMEOUT, 0 } }; @@ -3476,7 +3479,7 @@ int tcp_flow_migrate_source_ext(const struct ctx *c, if (c->migrate_no_linger) close(s); else - epoll_del(c->epollfd, s); + epoll_del(flow_epollfd(&conn->f), s);

/* Adjustments unrelated to FIN segments: sequence numbers we dumped are * based on the end of the queues. @@ -3625,7 +3628,7 @@ static int tcp_flow_repair_connect(const struct ctx *c, return rc; }

- conn->in_epoll = 0; + conn->f.threadnb = FLOW_THREADNB_INVALID; conn->timer = -1; conn->listening_sock = -1;

diff --git a/tcp_conn.h b/tcp_conn.h index 38b5c541f003..81333122d531 100644 --- a/tcp_conn.h +++ b/tcp_conn.h @@ -12,7 +12,6 @@ /** * struct tcp_tap_conn - Descriptor for a TCP connection (not spliced) * @f: Generic flow information - * @in_epoll: Is the connection in the epoll set? * @retrans: Number of retransmissions occurred due to ACK_TIMEOUT * @ws_from_tap: Window scaling factor advertised from tap/guest * @ws_to_tap: Window scaling factor advertised to tap/guest @@ -36,8 +35,6 @@ struct tcp_tap_conn { /* Must be first element */ struct flow_common f;

- bool in_epoll :1; - #define TCP_RETRANS_BITS 3 unsigned int retrans :TCP_RETRANS_BITS; #define TCP_MAX_RETRANS MAX_FROM_BITS(TCP_RETRANS_BITS) @@ -196,7 +193,6 @@ struct tcp_tap_transfer_ext { * @written: Bytes written (not fully written from one other side read) * @events: Events observed/actions performed on connection * @flags: Connection flags (attributes, not events) - * @in_epoll: Is the connection in the epoll set? */ struct tcp_splice_conn { /* Must be first element */ @@ -220,8 +216,6 @@ struct tcp_splice_conn { #define RCVLOWAT_SET(sidei_) ((sidei_) ? BIT(1) : BIT(0)) #define RCVLOWAT_ACT(sidei_) ((sidei_) ? BIT(3) : BIT(2)) #define CLOSING BIT(4) - - bool in_epoll :1; };

/* Socket pools */ @@ -245,7 +239,7 @@ int tcp_flow_migrate_target_ext(struct ctx *c, struct tcp_tap_conn *conn, int fd bool tcp_flow_is_established(const struct tcp_tap_conn *conn);

bool tcp_splice_flow_defer(struct tcp_splice_conn *conn); -void tcp_splice_timer(const struct ctx *c, struct tcp_splice_conn *conn); +void tcp_splice_timer(struct tcp_splice_conn *conn); int tcp_conn_pool_sock(int pool[]); int tcp_conn_sock(sa_family_t af); int tcp_sock_refill_pool(int pool[], sa_family_t af); diff --git a/tcp_splice.c b/tcp_splice.c index 6f21184bdc55..703bd7610890 100644 --- a/tcp_splice.c +++ b/tcp_splice.c @@ -149,7 +149,9 @@ static void tcp_splice_conn_epoll_events(uint16_t events, static int tcp_splice_epoll_ctl(const struct ctx *c, struct tcp_splice_conn *conn) { - int m = conn->in_epoll ? EPOLL_CTL_MOD : EPOLL_CTL_ADD; + int epollfd = flow_in_epoll(&conn->f) ? flow_epollfd(&conn->f) + : c->epollfd;

Same as above. Given the new, more limited usage of c->epollfd, if it's not a temporary thing (I couldn't quite guess what your plan is), maybe worth updating its documentation in struct ctx?

+ int m = flow_in_epoll(&conn->f) ? EPOLL_CTL_MOD : EPOLL_CTL_ADD; const union epoll_ref ref[SIDES] = { { .type = EPOLL_TYPE_TCP_SPLICE, .fd = conn->s[0], .flowside = FLOW_SIDX(conn, 0) }, @@ -161,25 +163,24 @@ static int tcp_splice_epoll_ctl(const struct ctx *c,

tcp_splice_conn_epoll_events(conn->events, ev);

- if (epoll_ctl(c->epollfd, m, conn->s[0], &ev[0]) || - epoll_ctl(c->epollfd, m, conn->s[1], &ev[1])) { + + if (epoll_ctl(epollfd, m, conn->s[0], &ev[0]) || + epoll_ctl(epollfd, m, conn->s[1], &ev[1])) { int ret = -errno; flow_perror(conn, "ERROR on epoll_ctl()"); return ret; } - - conn->in_epoll = true; + flow_thread_set(&conn->f, 0);

return 0; }

/** * conn_flag_do() - Set/unset given flag, log, update epoll on CLOSING flag - * @c: Execution context * @conn: Connection pointer * @flag: Flag to set, or ~flag to unset */ -static void conn_flag_do(const struct ctx *c, struct tcp_splice_conn *conn, +static void conn_flag_do(struct tcp_splice_conn *conn, unsigned long flag) { if (flag & (flag - 1)) { @@ -204,15 +205,15 @@ static void conn_flag_do(const struct ctx *c, struct tcp_splice_conn *conn, }

if (flag == CLOSING) { - epoll_del(c->epollfd, conn->s[0]); - epoll_del(c->epollfd, conn->s[1]); + epoll_del(flow_epollfd(&conn->f), conn->s[0]); + epoll_del(flow_epollfd(&conn->f), conn->s[1]); } }

#define conn_flag(c, conn, flag) \ do { \ flow_trace(conn, "flag at %s:%i", __func__, __LINE__); \ - conn_flag_do(c, conn, flag); \ + conn_flag_do(conn, flag); \ } while (0)

/** @@ -751,10 +752,9 @@ void tcp_splice_init(struct ctx *c)

/** * tcp_splice_timer() - Timer for spliced connections - * @c: Execution context * @conn: Connection to handle */ -void tcp_splice_timer(const struct ctx *c, struct tcp_splice_conn *conn) +void tcp_splice_timer(struct tcp_splice_conn *conn) { unsigned sidei;

-- Stefano

On Fri, Oct 17, 2025 at 12:31:27PM +0200, Laurent Vivier wrote:

Store the thread number in the flow_common structure for ICMP ping flows using flow_epollfd_set() and retrieve the corresponding epoll file descriptor with flow_epollfd_get() instead of passing c->epollfd directly. This makes ICMP consistent with the recent TCP changes and follows the pattern established in previous commit.

Signed-off-by: Laurent Vivier

Reviewed-by: David Gibson

--- icmp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/icmp.c b/icmp.c index 56dfac6c958e..baddd8e5aacb 100644 --- a/icmp.c +++ b/icmp.c @@ -149,7 +149,7 @@ unexpected: static void icmp_ping_close(const struct ctx *c, const struct icmp_ping_flow *pingf) { - epoll_del(c->epollfd, pingf->sock); + epoll_del(flow_epollfd(&pingf->f), pingf->sock); close(pingf->sock); flow_hash_remove(c, FLOW_SIDX(pingf, INISIDE)); } @@ -206,11 +206,13 @@ static struct icmp_ping_flow *icmp_ping_new(const struct ctx *c, if (pingf->sock > FD_REF_MAX) goto cancel;

+ flow_thread_set(&pingf->f, 0); + ref.type = EPOLL_TYPE_PING; ref.flowside = FLOW_SIDX(flow, TGTSIDE); ref.fd = pingf->sock;

- if (epoll_add(c->epollfd, EPOLLIN, &ref) < 0) { + if (epoll_add(flow_epollfd(&pingf->f), EPOLLIN, &ref) < 0) { close(pingf->sock); goto cancel; } -- 2.51.0

-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson

On Fri, Oct 17, 2025 at 12:31:26PM +0200, Laurent Vivier wrote:

The in_epoll boolean flag in tcp_tap_conn and tcp_splice_conn only tracked whether a connection was registered with epoll, not which epoll instance. This limited flexibility for future multi-epoll support.

Replace the boolean with a threadnb field in flow_common that identifies which thread (and thus which epoll instance) the flow is registered with. Use FLOW_THREADNB_INVALID to indicate when a flow is not registered with any epoll instance. A threadnb_to_epollfd[] mapping table translates thread numbers to their corresponding epoll file descriptors.

Add helper functions: - flow_in_epoll() to check if a flow is registered with epoll - flow_epollfd() to retrieve the epoll fd for a flow's thread - flow_thread_register() to register an epoll fd with a thread - flow_thread_set() to set the thread number of a flow

This change also simplifies tcp_timer_ctl() and conn_flag_do() by removing the need to pass the context 'c', since the epoll fd is now directly accessible from the flow structure via flow_epollfd().

Signed-off-by: Laurent Vivier

Some minor queries only.

--- flow.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++- flow.h | 12 ++++++++++++ passt.c | 1 + tcp.c | 39 ++++++++++++++++++++------------------ tcp_conn.h | 8 +------- tcp_splice.c | 24 ++++++++++++------------ 6 files changed, 99 insertions(+), 38 deletions(-)

diff --git a/flow.c b/flow.c index b14e9d8b63ff..d56bae776239 100644 --- a/flow.c +++ b/flow.c @@ -116,6 +116,7 @@ static_assert(ARRAY_SIZE(flow_proto) == FLOW_NUM_TYPES, unsigned flow_first_free; union flow flowtab[FLOW_MAX]; static const union flow *flow_new_entry; /* = NULL */ +static int threadnb_to_epollfd[FLOW_THREADNB_SIZE];

Same comments as in the previous version about "thread" in the name.

/* Hash table to index it */ #define FLOW_HASH_LOAD 70 /* % */ @@ -347,6 +348,55 @@ static void flow_set_state(struct flow_common *f, enum flow_state state) flow_log_details_(f, LOG_DEBUG, MAX(state, oldstate)); }

+/** + * flow_in_epoll() - Check if flow is registered with an epoll instance + * @f: Flow to check + * + * Return: true if flow is registered with epoll, false otherwise + */ +bool flow_in_epoll(const struct flow_common *f) +{ + return f->threadnb != FLOW_THREADNB_INVALID; +} + +/** + * flow_epollfd() - Get the epoll file descriptor for a flow + * @f: Flow to query + * + * Return: epoll file descriptor associated with the flow's thread + */ +int flow_epollfd(const struct flow_common *f) +{ + ASSERT(f->threadnb < FLOW_THREADNB_MAX); + + return threadnb_to_epollfd[f->threadnb]; +} + +/** + * flow_thread_set() - Associate a flow with a thread + * @f: Flow to update + * @threadnb: Thread number to associate with this flow + */ +void flow_thread_set(struct flow_common *f, int threadnb) +{ + ASSERT(threadnb < FLOW_THREADNB_MAX); + + f->threadnb = threadnb; +} + +/** + * flow_thread_register() - Initialize the threadnb -> epollfd mapping + * @threadnb: Thread number to associate to + * @epollfd: epoll file descriptor for the thread + */ +void flow_thread_register(int threadnb, int epollfd) +{ + ASSERT(threadnb < FLOW_THREADNB_MAX); + ASSERT(epollfd >= 0);

Not sure about the second assert. It seems like an error people are unlikely to make by accident, whereas attempting to deliberately clear / delete an entry by setting its fd to -1 seems like a reasonable thing to do.

+ + threadnb_to_epollfd[threadnb] = epollfd; +} + /** * flow_initiate_() - Move flow to INI, setting pif[INISIDE] * @flow: Flow to change state @@ -548,6 +598,7 @@ union flow *flow_alloc(void)

flow_new_entry = flow; memset(flow, 0, sizeof(*flow)); + flow->f.threadnb = FLOW_THREADNB_INVALID; flow_set_state(&flow->f, FLOW_STATE_NEW);

return flow; @@ -827,7 +878,7 @@ void flow_defer_handler(const struct ctx *c, const struct timespec *now) case FLOW_TCP_SPLICE: closed = tcp_splice_flow_defer(&flow->tcp_splice); if (!closed && timer) - tcp_splice_timer(c, &flow->tcp_splice); + tcp_splice_timer(&flow->tcp_splice); break; case FLOW_PING4: case FLOW_PING6: diff --git a/flow.h b/flow.h index ef138b83add8..700d8b32c990 100644 --- a/flow.h +++ b/flow.h @@ -177,6 +177,8 @@ int flowside_connect(const struct ctx *c, int s, * @type: Type of packet flow * @pif[]: Interface for each side of the flow * @side[]: Information for each side of the flow + * @threadnb: Thread number flow is registered with + * (FLOW_THREADNB_INVALID if not) */ struct flow_common { #ifdef __GNUC__ @@ -192,8 +194,14 @@ struct flow_common { #endif uint8_t pif[SIDES]; struct flowside side[SIDES]; +#define FLOW_THREADNB_BITS 8 + unsigned int threadnb:FLOW_THREADNB_BITS; };

+#define FLOW_THREADNB_SIZE (1 << FLOW_THREADNB_BITS) +#define FLOW_THREADNB_MAX (FLOW_THREADNB_SIZE - 1) +#define FLOW_THREADNB_INVALID FLOW_THREADNB_MAX + #define FLOW_INDEX_BITS 17 /* 128k - 1 */ #define FLOW_MAX MAX_FROM_BITS(FLOW_INDEX_BITS)

@@ -249,6 +257,10 @@ flow_sidx_t flow_lookup_sa(const struct ctx *c, uint8_t proto, uint8_t pif, union flow;

void flow_init(void); +bool flow_in_epoll(const struct flow_common *f); +int flow_epollfd(const struct flow_common *f); +void flow_thread_set(struct flow_common *f, int threadnb); +void flow_thread_register(int threadnb, int epollfd); void flow_defer_handler(const struct ctx *c, const struct timespec *now); int flow_migrate_source_early(struct ctx *c, const struct migrate_stage *stage, int fd); diff --git a/passt.c b/passt.c index af928111786b..37f2c897be84 100644 --- a/passt.c +++ b/passt.c @@ -285,6 +285,7 @@ int main(int argc, char **argv) c.epollfd = epoll_create1(EPOLL_CLOEXEC); if (c.epollfd == -1) die_perror("Failed to create epoll file descriptor"); + flow_thread_register(0, c.epollfd);

if (getrlimit(RLIMIT_NOFILE, &limit)) die_perror("Failed to get maximum value of open files limit"); diff --git a/tcp.c b/tcp.c index db9f17c0622f..8c49852b8454 100644 --- a/tcp.c +++ b/tcp.c @@ -504,25 +504,27 @@ static uint32_t tcp_conn_epoll_events(uint8_t events, uint8_t conn_flags) */ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn) { - int m = conn->in_epoll ? EPOLL_CTL_MOD : EPOLL_CTL_ADD; + int m = flow_in_epoll(&conn->f) ? EPOLL_CTL_MOD : EPOLL_CTL_ADD; union epoll_ref ref = { .type = EPOLL_TYPE_TCP, .fd = conn->sock, .flowside = FLOW_SIDX(conn, !TAPSIDE(conn)), }; struct epoll_event ev = { .data.u64 = ref.u64 }; + int epollfd = flow_in_epoll(&conn->f) ? flow_epollfd(&conn->f) + : c->epollfd;

if (conn->events == CLOSED) { - if (conn->in_epoll) - epoll_del(c->epollfd, conn->sock); + if (flow_in_epoll(&conn->f)) + epoll_del(epollfd, conn->sock); if (conn->timer != -1) - epoll_del(c->epollfd, conn->timer); + epoll_del(epollfd, conn->timer); return 0; }

ev.events = tcp_conn_epoll_events(conn->events, conn->flags);

- if (epoll_ctl(c->epollfd, m, conn->sock, &ev)) + if (epoll_ctl(epollfd, m, conn->sock, &ev)) return -errno;

- conn->in_epoll = true; + flow_thread_set(&conn->f, 0);

if (conn->timer != -1) { union epoll_ref ref_t = { .type = EPOLL_TYPE_TCP_TIMER, @@ -531,7 +533,8 @@ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn) struct epoll_event ev_t = { .data.u64 = ref_t.u64, .events = EPOLLIN | EPOLLET };

- if (epoll_ctl(c->epollfd, EPOLL_CTL_MOD, conn->timer, &ev_t)) + if (epoll_ctl(flow_epollfd(&conn->f), EPOLL_CTL_MOD, + conn->timer, &ev_t)) return -errno; }

@@ -540,12 +543,11 @@ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn)

/** * tcp_timer_ctl() - Set timerfd based on flags/events, create timerfd if needed - * @c: Execution context * @conn: Connection pointer * * #syscalls timerfd_create timerfd_settime */ -static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn) +static void tcp_timer_ctl(struct tcp_tap_conn *conn) { struct itimerspec it = { { 0 }, { 0 } };

@@ -570,7 +572,8 @@ static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn) } conn->timer = fd;

- if (epoll_ctl(c->epollfd, EPOLL_CTL_ADD, conn->timer, &ev)) { + if (epoll_ctl(flow_epollfd(&conn->f), EPOLL_CTL_ADD, + conn->timer, &ev)) {

Possibly a question for an earlier patch, but is there a reason we can't use epoll_add() here?

flow_dbg_perror(conn, "failed to add timer"); close(conn->timer); conn->timer = -1; @@ -628,7 +631,7 @@ void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn, * flags and factor this into the logic below. */ if (flag == ACK_FROM_TAP_DUE) - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn);

return; } @@ -644,7 +647,7 @@ void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn, if (flag == ACK_FROM_TAP_DUE || flag == ACK_TO_TAP_DUE || (flag == ~ACK_FROM_TAP_DUE && (conn->flags & ACK_TO_TAP_DUE)) || (flag == ~ACK_TO_TAP_DUE && (conn->flags & ACK_FROM_TAP_DUE))) - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); }

/** @@ -699,7 +702,7 @@ void conn_event_do(const struct ctx *c, struct tcp_tap_conn *conn, tcp_epoll_ctl(c, conn);

if (CONN_HAS(conn, SOCK_FIN_SENT | TAP_FIN_ACKED)) - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); }

/** @@ -1757,7 +1760,7 @@ static int tcp_data_from_tap(const struct ctx *c, struct tcp_tap_conn *conn, seq, conn->seq_from_tap);

tcp_send_flag(c, conn, ACK); - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn);

if (p->count == 1) { tcp_tap_window_update(c, conn, @@ -2406,7 +2409,7 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref)

if (conn->flags & ACK_TO_TAP_DUE) { tcp_send_flag(c, conn, ACK_IF_NEEDED); - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); } else if (conn->flags & ACK_FROM_TAP_DUE) { if (!(conn->events & ESTABLISHED)) { flow_dbg(conn, "handshake timeout"); @@ -2428,7 +2431,7 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref) return;

tcp_data_from_sock(c, conn); - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); } } else { struct itimerspec new = { { 0 }, { ACT_TIMEOUT, 0 } }; @@ -3476,7 +3479,7 @@ int tcp_flow_migrate_source_ext(const struct ctx *c, if (c->migrate_no_linger) close(s); else - epoll_del(c->epollfd, s); + epoll_del(flow_epollfd(&conn->f), s);

/* Adjustments unrelated to FIN segments: sequence numbers we dumped are * based on the end of the queues. @@ -3625,7 +3628,7 @@ static int tcp_flow_repair_connect(const struct ctx *c, return rc; }

- conn->in_epoll = 0; + conn->f.threadnb = FLOW_THREADNB_INVALID; conn->timer = -1; conn->listening_sock = -1;

diff --git a/tcp_conn.h b/tcp_conn.h index 38b5c541f003..81333122d531 100644 --- a/tcp_conn.h +++ b/tcp_conn.h @@ -12,7 +12,6 @@ /** * struct tcp_tap_conn - Descriptor for a TCP connection (not spliced) * @f: Generic flow information - * @in_epoll: Is the connection in the epoll set? * @retrans: Number of retransmissions occurred due to ACK_TIMEOUT * @ws_from_tap: Window scaling factor advertised from tap/guest * @ws_to_tap: Window scaling factor advertised to tap/guest @@ -36,8 +35,6 @@ struct tcp_tap_conn { /* Must be first element */ struct flow_common f;

- bool in_epoll :1; - #define TCP_RETRANS_BITS 3 unsigned int retrans :TCP_RETRANS_BITS; #define TCP_MAX_RETRANS MAX_FROM_BITS(TCP_RETRANS_BITS) @@ -196,7 +193,6 @@ struct tcp_tap_transfer_ext { * @written: Bytes written (not fully written from one other side read) * @events: Events observed/actions performed on connection * @flags: Connection flags (attributes, not events) - * @in_epoll: Is the connection in the epoll set? */ struct tcp_splice_conn { /* Must be first element */ @@ -220,8 +216,6 @@ struct tcp_splice_conn { #define RCVLOWAT_SET(sidei_) ((sidei_) ? BIT(1) : BIT(0)) #define RCVLOWAT_ACT(sidei_) ((sidei_) ? BIT(3) : BIT(2)) #define CLOSING BIT(4) - - bool in_epoll :1; };

/* Socket pools */ @@ -245,7 +239,7 @@ int tcp_flow_migrate_target_ext(struct ctx *c, struct tcp_tap_conn *conn, int fd bool tcp_flow_is_established(const struct tcp_tap_conn *conn);

bool tcp_splice_flow_defer(struct tcp_splice_conn *conn); -void tcp_splice_timer(const struct ctx *c, struct tcp_splice_conn *conn); +void tcp_splice_timer(struct tcp_splice_conn *conn); int tcp_conn_pool_sock(int pool[]); int tcp_conn_sock(sa_family_t af); int tcp_sock_refill_pool(int pool[], sa_family_t af); diff --git a/tcp_splice.c b/tcp_splice.c index 6f21184bdc55..703bd7610890 100644 --- a/tcp_splice.c +++ b/tcp_splice.c @@ -149,7 +149,9 @@ static void tcp_splice_conn_epoll_events(uint16_t events, static int tcp_splice_epoll_ctl(const struct ctx *c, struct tcp_splice_conn *conn) { - int m = conn->in_epoll ? EPOLL_CTL_MOD : EPOLL_CTL_ADD; + int epollfd = flow_in_epoll(&conn->f) ? flow_epollfd(&conn->f) + : c->epollfd; + int m = flow_in_epoll(&conn->f) ? EPOLL_CTL_MOD : EPOLL_CTL_ADD; const union epoll_ref ref[SIDES] = { { .type = EPOLL_TYPE_TCP_SPLICE, .fd = conn->s[0], .flowside = FLOW_SIDX(conn, 0) }, @@ -161,25 +163,24 @@ static int tcp_splice_epoll_ctl(const struct ctx *c,

tcp_splice_conn_epoll_events(conn->events, ev);

- if (epoll_ctl(c->epollfd, m, conn->s[0], &ev[0]) || - epoll_ctl(c->epollfd, m, conn->s[1], &ev[1])) { + + if (epoll_ctl(epollfd, m, conn->s[0], &ev[0]) || + epoll_ctl(epollfd, m, conn->s[1], &ev[1])) { int ret = -errno; flow_perror(conn, "ERROR on epoll_ctl()"); return ret; } - - conn->in_epoll = true; + flow_thread_set(&conn->f, 0);

return 0; }

/** * conn_flag_do() - Set/unset given flag, log, update epoll on CLOSING flag - * @c: Execution context * @conn: Connection pointer * @flag: Flag to set, or ~flag to unset */ -static void conn_flag_do(const struct ctx *c, struct tcp_splice_conn *conn, +static void conn_flag_do(struct tcp_splice_conn *conn, unsigned long flag) { if (flag & (flag - 1)) { @@ -204,15 +205,15 @@ static void conn_flag_do(const struct ctx *c, struct tcp_splice_conn *conn, }

if (flag == CLOSING) { - epoll_del(c->epollfd, conn->s[0]); - epoll_del(c->epollfd, conn->s[1]); + epoll_del(flow_epollfd(&conn->f), conn->s[0]); + epoll_del(flow_epollfd(&conn->f), conn->s[1]); } }

#define conn_flag(c, conn, flag) \ do { \ flow_trace(conn, "flag at %s:%i", __func__, __LINE__); \ - conn_flag_do(c, conn, flag); \ + conn_flag_do(conn, flag); \ } while (0)

/** @@ -751,10 +752,9 @@ void tcp_splice_init(struct ctx *c)

/** * tcp_splice_timer() - Timer for spliced connections - * @c: Execution context * @conn: Connection to handle */ -void tcp_splice_timer(const struct ctx *c, struct tcp_splice_conn *conn) +void tcp_splice_timer(struct tcp_splice_conn *conn) { unsigned sidei;

-- 2.51.0

-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson

On Fri, Oct 17, 2025 at 12:31:29PM +0200, Laurent Vivier wrote:

Extract the epoll event processing logic from main() into a separate passt_worker() function. This refactoring prepares the code for future threading support where passt_worker() will be called as a worker thread callback.

The new function handles: - Processing epoll events and dispatching to protocol handlers - Event statistics tracking and printing - Post-handler periodic tasks (timers, deferred work) - Migration handling

No functional changes, purely a code restructuring.

Signed-off-by: Laurent Vivier

Looks good as far as it goes, and I've though often in the past that it would make more sense for the "engine" to go in its own function. Wondering if it would make more sense to include the epoll_wait() itself and the loop in this function, rather than leaving that outside.

--- passt.c | 160 +++++++++++++++++++++++++++++++------------------------- 1 file changed, 88 insertions(+), 72 deletions(-)

diff --git a/passt.c b/passt.c index 37f2c897be84..5bfa4c6353d9 100644 --- a/passt.c +++ b/passt.c @@ -229,6 +229,92 @@ static void print_stats(const struct ctx *c, const struct passt_stats *stats, lines_printed++; }

+/** + * passt_worker() - Process epoll events and handle protocol operations + * @opaque: Pointer to execution context (struct ctx) + * @nfds: Number of file descriptors ready (epoll_wait return value) + * @events: epoll_event array of ready file descriptors + */ +static void passt_worker(void *opaque, int nfds, struct epoll_event *events) +{ + static struct passt_stats stats = { 0 }; + struct ctx *c = opaque; + struct timespec now; + int i; + + if (clock_gettime(CLOCK_MONOTONIC, &now)) + err_perror("Failed to get CLOCK_MONOTONIC time"); + + for (i = 0; i < nfds; i++) { + union epoll_ref ref = *((union epoll_ref *)&events[i].data.u64); + uint32_t eventmask = events[i].events; + + trace("%s: epoll event on %s %i (events: 0x%08x)", + c->mode == MODE_PASTA ? "pasta" : "passt", + EPOLL_TYPE_STR(ref.type), ref.fd, eventmask); + + switch (ref.type) { + case EPOLL_TYPE_TAP_PASTA: + tap_handler_pasta(c, eventmask, &now); + break; + case EPOLL_TYPE_TAP_PASST: + tap_handler_passt(c, eventmask, &now); + break; + case EPOLL_TYPE_TAP_LISTEN: + tap_listen_handler(c, eventmask); + break; + case EPOLL_TYPE_NSQUIT_INOTIFY: + pasta_netns_quit_inotify_handler(c, ref.fd); + break; + case EPOLL_TYPE_NSQUIT_TIMER: + pasta_netns_quit_timer_handler(c, ref); + break; + case EPOLL_TYPE_TCP: + tcp_sock_handler(c, ref, eventmask); + break; + case EPOLL_TYPE_TCP_SPLICE: + tcp_splice_sock_handler(c, ref, eventmask); + break; + case EPOLL_TYPE_TCP_LISTEN: + tcp_listen_handler(c, ref, &now); + break; + case EPOLL_TYPE_TCP_TIMER: + tcp_timer_handler(c, ref); + break; + case EPOLL_TYPE_UDP_LISTEN: + udp_listen_sock_handler(c, ref, eventmask, &now); + break; + case EPOLL_TYPE_UDP: + udp_sock_handler(c, ref, eventmask, &now); + break; + case EPOLL_TYPE_PING: + icmp_sock_handler(c, ref); + break; + case EPOLL_TYPE_VHOST_CMD: + vu_control_handler(c->vdev, c->fd_tap, eventmask); + break; + case EPOLL_TYPE_VHOST_KICK: + vu_kick_cb(c->vdev, ref, &now); + break; + case EPOLL_TYPE_REPAIR_LISTEN: + repair_listen_handler(c, eventmask); + break; + case EPOLL_TYPE_REPAIR: + repair_handler(c, eventmask); + break; + default: + /* Can't happen */ + ASSERT(0); + } + stats.events[ref.type]++; + print_stats(c, &stats, &now); + } + + post_handler(c, &now); + + migrate_handler(c); +} + /** * main() - Entry point and main loop * @argc: Argument count @@ -246,8 +332,7 @@ static void print_stats(const struct ctx *c, const struct passt_stats *stats, int main(int argc, char **argv) { struct epoll_event events[NUM_EPOLL_EVENTS]; - struct passt_stats stats = { 0 }; - int nfds, i, devnull_fd = -1; + int nfds, devnull_fd = -1; struct ctx c = { 0 }; struct rlimit limit; struct timespec now; @@ -355,77 +440,8 @@ loop: if (nfds == -1 && errno != EINTR) die_perror("epoll_wait() failed in main loop");

- if (clock_gettime(CLOCK_MONOTONIC, &now)) - err_perror("Failed to get CLOCK_MONOTONIC time"); - - for (i = 0; i < nfds; i++) { - union epoll_ref ref = *((union epoll_ref *)&events[i].data.u64); - uint32_t eventmask = events[i].events; - - trace("%s: epoll event on %s %i (events: 0x%08x)", - c.mode == MODE_PASTA ? "pasta" : "passt", - EPOLL_TYPE_STR(ref.type), ref.fd, eventmask); - - switch (ref.type) { - case EPOLL_TYPE_TAP_PASTA: - tap_handler_pasta(&c, eventmask, &now); - break; - case EPOLL_TYPE_TAP_PASST: - tap_handler_passt(&c, eventmask, &now); - break; - case EPOLL_TYPE_TAP_LISTEN: - tap_listen_handler(&c, eventmask); - break; - case EPOLL_TYPE_NSQUIT_INOTIFY: - pasta_netns_quit_inotify_handler(&c, ref.fd); - break; - case EPOLL_TYPE_NSQUIT_TIMER: - pasta_netns_quit_timer_handler(&c, ref); - break; - case EPOLL_TYPE_TCP: - tcp_sock_handler(&c, ref, eventmask); - break; - case EPOLL_TYPE_TCP_SPLICE: - tcp_splice_sock_handler(&c, ref, eventmask); - break; - case EPOLL_TYPE_TCP_LISTEN: - tcp_listen_handler(&c, ref, &now); - break; - case EPOLL_TYPE_TCP_TIMER: - tcp_timer_handler(&c, ref); - break; - case EPOLL_TYPE_UDP_LISTEN: - udp_listen_sock_handler(&c, ref, eventmask, &now); - break; - case EPOLL_TYPE_UDP: - udp_sock_handler(&c, ref, eventmask, &now); - break; - case EPOLL_TYPE_PING: - icmp_sock_handler(&c, ref); - break; - case EPOLL_TYPE_VHOST_CMD: - vu_control_handler(c.vdev, c.fd_tap, eventmask); - break; - case EPOLL_TYPE_VHOST_KICK: - vu_kick_cb(c.vdev, ref, &now); - break; - case EPOLL_TYPE_REPAIR_LISTEN: - repair_listen_handler(&c, eventmask); - break; - case EPOLL_TYPE_REPAIR: - repair_handler(&c, eventmask); - break; - default: - /* Can't happen */ - ASSERT(0); - } - stats.events[ref.type]++; - print_stats(&c, &stats, &now); - } - - post_handler(&c, &now);

- migrate_handler(&c); + passt_worker(&c, nfds, events);

goto loop; } -- 2.51.0

-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson

On 20/10/2025 03:20, David Gibson wrote:

On Fri, Oct 17, 2025 at 12:31:24PM +0200, Laurent Vivier wrote:

...

Centralize epoll_add() and epoll_del() helper functions into new epoll_ctl.c/h files.

This also moves the union epoll_ref definition from passt.h to epoll_ctl.h where it's more logically placed.

The new epoll_add() helper simplifies adding file descriptors to epoll by taking an epoll_ref and events, handling error reporting consistently across all call sites.

Signed-off-by: Laurent Vivier

Concept looks good, some minor details in execution.

...

--- Makefile | 22 +++++++++++----------- epoll_ctl.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ epoll_ctl.h | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++ icmp.c | 4 +--- passt.c | 2 +- passt.h | 34 ---------------------------------- pasta.c | 7 +++---- repair.c | 14 +++++--------- tap.c | 13 ++++--------- tcp.c | 2 +- tcp_splice.c | 2 +- udp.c | 2 +- udp_flow.c | 1 + util.c | 22 +++------------------- util.h | 4 +++- vhost_user.c | 8 ++------ vu_common.c | 2 +- 17 files changed, 134 insertions(+), 101 deletions(-) create mode 100644 epoll_ctl.c create mode 100644 epoll_ctl.h ... @@ -1327,14 +1327,12 @@ static void tap_backend_show_hints(struct ctx *c) static void tap_sock_unix_init(const struct ctx *c) { union epoll_ref ref = { .type = EPOLL_TYPE_TAP_LISTEN }; - struct epoll_event ev = { 0 };

listen(c->fd_tap_listen, 0);

ref.fd = c->fd_tap_listen; - ev.events = EPOLLIN | EPOLLET; - ev.data.u64 = ref.u64; - epoll_ctl(c->epollfd, EPOLL_CTL_ADD, c->fd_tap_listen, &ev); + + epoll_add(c->epollfd, EPOLLIN | EPOLLET, &ref);

Preexisting, but we should probably check for errors here.

To do what? die() ? err() to report the place where the error happens? Thanks, Laurent

On 17/10/2025 19:43, Stefano Brivio wrote:

Nits only:

On Fri, 17 Oct 2025 12:31:26 +0200 Laurent Vivier wrote:

...

The in_epoll boolean flag in tcp_tap_conn and tcp_splice_conn only tracked whether a connection was registered with epoll, not which epoll instance. This limited flexibility for future multi-epoll support.

Replace the boolean with a threadnb field in flow_common that identifies which thread (and thus which epoll instance) the flow is registered with. Use FLOW_THREADNB_INVALID to indicate when a flow is not registered with any epoll instance. A threadnb_to_epollfd[] mapping table translates thread numbers to their corresponding epoll file descriptors.

It wasn't really clear to me until I actually started digging into this change what NB meant there. For me it's "notifier block" before "number", but that didn't make sense either.

Some ideas (even though maybe as David suggested this name shouldn't have "thread" in it at all):

- f->thread / FLOW_THREAD_INVALID

- f->thread_id / FLOW_THREAD_ID_INVALID

...or f->epoll_id, reflecting David's observation?

epoll_id seems reasonable.

...

Add helper functions: - flow_in_epoll() to check if a flow is registered with epoll - flow_epollfd() to retrieve the epoll fd for a flow's thread - flow_thread_register() to register an epoll fd with a thread - flow_thread_set() to set the thread number of a flow

This change also simplifies tcp_timer_ctl() and conn_flag_do() by removing the need to pass the context 'c', since the epoll fd is now directly accessible from the flow structure via flow_epollfd().

Signed-off-by: Laurent Vivier --- flow.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++- flow.h | 12 ++++++++++++ passt.c | 1 + tcp.c | 39 ++++++++++++++++++++------------------ tcp_conn.h | 8 +------- tcp_splice.c | 24 ++++++++++++------------ 6 files changed, 99 insertions(+), 38 deletions(-)

diff --git a/flow.c b/flow.c index b14e9d8b63ff..d56bae776239 100644 --- a/flow.c +++ b/flow.c @@ -116,6 +116,7 @@ static_assert(ARRAY_SIZE(flow_proto) == FLOW_NUM_TYPES, unsigned flow_first_free; union flow flowtab[FLOW_MAX]; static const union flow *flow_new_entry; /* = NULL */

It would be nice to have an idea of how this table is organised without looking at how it's used, say:

/* Table of epoll file descriptors, indexed by thread number */

...or indexed by "epoll identifiers", perhaps, if we want to drop references to threads here.

I will drop reference to threads.

...

+static int threadnb_to_epollfd[FLOW_THREADNB_SIZE];

/* Hash table to index it */ #define FLOW_HASH_LOAD 70 /* % */ @@ -347,6 +348,55 @@ static void flow_set_state(struct flow_common *f, enum flow_state state) flow_log_details_(f, LOG_DEBUG, MAX(state, oldstate)); }

+/** + * flow_in_epoll() - Check if flow is registered with an epoll instance + * @f: Flow to check + * + * Return: true if flow is registered with epoll, false otherwise + */ +bool flow_in_epoll(const struct flow_common *f) +{ + return f->threadnb != FLOW_THREADNB_INVALID; +} + +/** + * flow_epollfd() - Get the epoll file descriptor for a flow + * @f: Flow to query + * + * Return: epoll file descriptor associated with the flow's thread + */ +int flow_epollfd(const struct flow_common *f) +{ + ASSERT(f->threadnb < FLOW_THREADNB_MAX); + + return threadnb_to_epollfd[f->threadnb]; +} + +/** + * flow_thread_set() - Associate a flow with a thread + * @f: Flow to update + * @threadnb: Thread number to associate with this flow + */ +void flow_thread_set(struct flow_common *f, int threadnb) +{ + ASSERT(threadnb < FLOW_THREADNB_MAX); + + f->threadnb = threadnb; +} + +/** + * flow_thread_register() - Initialize the threadnb -> epollfd mapping + * @threadnb: Thread number to associate to + * @epollfd: epoll file descriptor for the thread + */ +void flow_thread_register(int threadnb, int epollfd) +{ + ASSERT(threadnb < FLOW_THREADNB_MAX); + ASSERT(epollfd >= 0); + + threadnb_to_epollfd[threadnb] = epollfd; +} + /** * flow_initiate_() - Move flow to INI, setting pif[INISIDE] * @flow: Flow to change state @@ -548,6 +598,7 @@ union flow *flow_alloc(void)

flow_new_entry = flow; memset(flow, 0, sizeof(*flow)); + flow->f.threadnb = FLOW_THREADNB_INVALID; flow_set_state(&flow->f, FLOW_STATE_NEW);

return flow; @@ -827,7 +878,7 @@ void flow_defer_handler(const struct ctx *c, const struct timespec *now) case FLOW_TCP_SPLICE: closed = tcp_splice_flow_defer(&flow->tcp_splice); if (!closed && timer) - tcp_splice_timer(c, &flow->tcp_splice); + tcp_splice_timer(&flow->tcp_splice); break; case FLOW_PING4: case FLOW_PING6: diff --git a/flow.h b/flow.h index ef138b83add8..700d8b32c990 100644 --- a/flow.h +++ b/flow.h @@ -177,6 +177,8 @@ int flowside_connect(const struct ctx *c, int s, * @type: Type of packet flow * @pif[]: Interface for each side of the flow * @side[]: Information for each side of the flow + * @threadnb: Thread number flow is registered with + * (FLOW_THREADNB_INVALID if not)

You could phrase this more directly, say, "thread identifier, or FLOW_THREAD_INVALID", or "epollfd identifier, or EPOLLFD_ID_INVALID".

This is a structure describing flows, it's not surprising it's about the flow.

...

*/ struct flow_common { #ifdef __GNUC__ @@ -192,8 +194,14 @@ struct flow_common { #endif uint8_t pif[SIDES]; struct flowside side[SIDES]; +#define FLOW_THREADNB_BITS 8 + unsigned int threadnb:FLOW_THREADNB_BITS; };

+#define FLOW_THREADNB_SIZE (1 << FLOW_THREADNB_BITS) +#define FLOW_THREADNB_MAX (FLOW_THREADNB_SIZE - 1) +#define FLOW_THREADNB_INVALID FLOW_THREADNB_MAX + #define FLOW_INDEX_BITS 17 /* 128k - 1 */ #define FLOW_MAX MAX_FROM_BITS(FLOW_INDEX_BITS)

@@ -249,6 +257,10 @@ flow_sidx_t flow_lookup_sa(const struct ctx *c, uint8_t proto, uint8_t pif, union flow;

void flow_init(void); +bool flow_in_epoll(const struct flow_common *f); +int flow_epollfd(const struct flow_common *f); +void flow_thread_set(struct flow_common *f, int threadnb); +void flow_thread_register(int threadnb, int epollfd); void flow_defer_handler(const struct ctx *c, const struct timespec *now); int flow_migrate_source_early(struct ctx *c, const struct migrate_stage *stage, int fd); diff --git a/passt.c b/passt.c index af928111786b..37f2c897be84 100644 --- a/passt.c +++ b/passt.c @@ -285,6 +285,7 @@ int main(int argc, char **argv) c.epollfd = epoll_create1(EPOLL_CLOEXEC); if (c.epollfd == -1) die_perror("Failed to create epoll file descriptor"); + flow_thread_register(0, c.epollfd);

Temporary, I suppose. If not, maybe it deserves its own constant, such as EPOLLFD_ID_DEFAULT?

I agree

...

if (getrlimit(RLIMIT_NOFILE, &limit)) die_perror("Failed to get maximum value of open files limit"); diff --git a/tcp.c b/tcp.c index db9f17c0622f..8c49852b8454 100644 --- a/tcp.c +++ b/tcp.c @@ -504,25 +504,27 @@ static uint32_t tcp_conn_epoll_events(uint8_t events, uint8_t conn_flags) */ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn) { - int m = conn->in_epoll ? EPOLL_CTL_MOD : EPOLL_CTL_ADD; + int m = flow_in_epoll(&conn->f) ? EPOLL_CTL_MOD : EPOLL_CTL_ADD; union epoll_ref ref = { .type = EPOLL_TYPE_TCP, .fd = conn->sock, .flowside = FLOW_SIDX(conn, !TAPSIDE(conn)), }; struct epoll_event ev = { .data.u64 = ref.u64 }; + int epollfd = flow_in_epoll(&conn->f) ? flow_epollfd(&conn->f) + : c->epollfd;

We usually align the second expression to the ternary operator, see also example in sock_l4_sa(), say:

int epollfd = flow_in_epoll(&conn->f) ? flow_epollfd(&conn->f) : c->epollfd;

I do like this usually. Missed this one when I change the name of the function.

...

if (conn->events == CLOSED) { - if (conn->in_epoll) - epoll_del(c->epollfd, conn->sock); + if (flow_in_epoll(&conn->f)) + epoll_del(epollfd, conn->sock); if (conn->timer != -1) - epoll_del(c->epollfd, conn->timer); + epoll_del(epollfd, conn->timer); return 0; }

ev.events = tcp_conn_epoll_events(conn->events, conn->flags);

- if (epoll_ctl(c->epollfd, m, conn->sock, &ev)) + if (epoll_ctl(epollfd, m, conn->sock, &ev)) return -errno;

- conn->in_epoll = true; + flow_thread_set(&conn->f, 0);

Not temporary I guess, maybe it's an EPOLLFD_ID_DEFAULT?

I agree

...

if (conn->timer != -1) { union epoll_ref ref_t = { .type = EPOLL_TYPE_TCP_TIMER, @@ -531,7 +533,8 @@ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn) struct epoll_event ev_t = { .data.u64 = ref_t.u64, .events = EPOLLIN | EPOLLET };

- if (epoll_ctl(c->epollfd, EPOLL_CTL_MOD, conn->timer, &ev_t)) + if (epoll_ctl(flow_epollfd(&conn->f), EPOLL_CTL_MOD, + conn->timer, &ev_t)) return -errno; }

@@ -540,12 +543,11 @@ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn)

/** * tcp_timer_ctl() - Set timerfd based on flags/events, create timerfd if needed - * @c: Execution context * @conn: Connection pointer * * #syscalls timerfd_create timerfd_settime */ -static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn) +static void tcp_timer_ctl(struct tcp_tap_conn *conn) { struct itimerspec it = { { 0 }, { 0 } };

@@ -570,7 +572,8 @@ static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn) } conn->timer = fd;

- if (epoll_ctl(c->epollfd, EPOLL_CTL_ADD, conn->timer, &ev)) { + if (epoll_ctl(flow_epollfd(&conn->f), EPOLL_CTL_ADD,

I wouldn't find it outrageous if you assigned an epollfd local variable first so that this doesn't need two lines.

I will do...

...

+ conn->timer, &ev)) { flow_dbg_perror(conn, "failed to add timer"); close(conn->timer); conn->timer = -1; @@ -628,7 +631,7 @@ void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn, * flags and factor this into the logic below. */ if (flag == ACK_FROM_TAP_DUE) - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn);

return; } @@ -644,7 +647,7 @@ void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn, if (flag == ACK_FROM_TAP_DUE || flag == ACK_TO_TAP_DUE || (flag == ~ACK_FROM_TAP_DUE && (conn->flags & ACK_TO_TAP_DUE)) || (flag == ~ACK_TO_TAP_DUE && (conn->flags & ACK_FROM_TAP_DUE))) - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); }

/** @@ -699,7 +702,7 @@ void conn_event_do(const struct ctx *c, struct tcp_tap_conn *conn, tcp_epoll_ctl(c, conn);

if (CONN_HAS(conn, SOCK_FIN_SENT | TAP_FIN_ACKED)) - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); }

/** @@ -1757,7 +1760,7 @@ static int tcp_data_from_tap(const struct ctx *c, struct tcp_tap_conn *conn, seq, conn->seq_from_tap);

tcp_send_flag(c, conn, ACK); - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn);

if (p->count == 1) { tcp_tap_window_update(c, conn, @@ -2406,7 +2409,7 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref)

if (conn->flags & ACK_TO_TAP_DUE) { tcp_send_flag(c, conn, ACK_IF_NEEDED); - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); } else if (conn->flags & ACK_FROM_TAP_DUE) { if (!(conn->events & ESTABLISHED)) { flow_dbg(conn, "handshake timeout"); @@ -2428,7 +2431,7 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref) return;

tcp_data_from_sock(c, conn); - tcp_timer_ctl(c, conn); + tcp_timer_ctl(conn); } } else { struct itimerspec new = { { 0 }, { ACT_TIMEOUT, 0 } }; @@ -3476,7 +3479,7 @@ int tcp_flow_migrate_source_ext(const struct ctx *c, if (c->migrate_no_linger) close(s); else - epoll_del(c->epollfd, s); + epoll_del(flow_epollfd(&conn->f), s);

/* Adjustments unrelated to FIN segments: sequence numbers we dumped are * based on the end of the queues. @@ -3625,7 +3628,7 @@ static int tcp_flow_repair_connect(const struct ctx *c, return rc; }

- conn->in_epoll = 0; + conn->f.threadnb = FLOW_THREADNB_INVALID; conn->timer = -1; conn->listening_sock = -1;

diff --git a/tcp_conn.h b/tcp_conn.h index 38b5c541f003..81333122d531 100644 --- a/tcp_conn.h +++ b/tcp_conn.h @@ -12,7 +12,6 @@ /** * struct tcp_tap_conn - Descriptor for a TCP connection (not spliced) * @f: Generic flow information - * @in_epoll: Is the connection in the epoll set? * @retrans: Number of retransmissions occurred due to ACK_TIMEOUT * @ws_from_tap: Window scaling factor advertised from tap/guest * @ws_to_tap: Window scaling factor advertised to tap/guest @@ -36,8 +35,6 @@ struct tcp_tap_conn { /* Must be first element */ struct flow_common f;

- bool in_epoll :1; - #define TCP_RETRANS_BITS 3 unsigned int retrans :TCP_RETRANS_BITS; #define TCP_MAX_RETRANS MAX_FROM_BITS(TCP_RETRANS_BITS) @@ -196,7 +193,6 @@ struct tcp_tap_transfer_ext { * @written: Bytes written (not fully written from one other side read) * @events: Events observed/actions performed on connection * @flags: Connection flags (attributes, not events) - * @in_epoll: Is the connection in the epoll set? */ struct tcp_splice_conn { /* Must be first element */ @@ -220,8 +216,6 @@ struct tcp_splice_conn { #define RCVLOWAT_SET(sidei_) ((sidei_) ? BIT(1) : BIT(0)) #define RCVLOWAT_ACT(sidei_) ((sidei_) ? BIT(3) : BIT(2)) #define CLOSING BIT(4) - - bool in_epoll :1; };

/* Socket pools */ @@ -245,7 +239,7 @@ int tcp_flow_migrate_target_ext(struct ctx *c, struct tcp_tap_conn *conn, int fd bool tcp_flow_is_established(const struct tcp_tap_conn *conn);

bool tcp_splice_flow_defer(struct tcp_splice_conn *conn); -void tcp_splice_timer(const struct ctx *c, struct tcp_splice_conn *conn); +void tcp_splice_timer(struct tcp_splice_conn *conn); int tcp_conn_pool_sock(int pool[]); int tcp_conn_sock(sa_family_t af); int tcp_sock_refill_pool(int pool[], sa_family_t af); diff --git a/tcp_splice.c b/tcp_splice.c index 6f21184bdc55..703bd7610890 100644 --- a/tcp_splice.c +++ b/tcp_splice.c @@ -149,7 +149,9 @@ static void tcp_splice_conn_epoll_events(uint16_t events, static int tcp_splice_epoll_ctl(const struct ctx *c, struct tcp_splice_conn *conn) { - int m = conn->in_epoll ? EPOLL_CTL_MOD : EPOLL_CTL_ADD; + int epollfd = flow_in_epoll(&conn->f) ? flow_epollfd(&conn->f) + : c->epollfd;

Same as above.

Given the new, more limited usage of c->epollfd, if it's not a temporary thing (I couldn't quite guess what your plan is), maybe worth updating its documentation in struct ctx?

In a later patch I remove epollfd from ctx and rely on the threadnb (0 for main) to get epollfd. Thansk, Laurent