Re: [PATCH v8 6/6] tcp: Clamp the retry timeout

On Mon, Nov 17, 2025 at 10:38:52AM +0800, Yumei Huang wrote:

On Fri, Nov 14, 2025 at 12:19 PM David Gibson wrote:

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On Fri, Nov 14, 2025 at 11:05:51AM +0800, Yumei Huang wrote:

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On Fri, Nov 14, 2025 at 8:47 AM David Gibson wrote:

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> @@ -2811,10 +2821,15 @@ void tcp_get_rto_params(struct ctx *c) > v = read_file_integer(SYN_LINEAR_TIMEOUTS, SYN_LINEAR_TIMEOUTS_DEFAULT); > c->tcp.syn_linear_timeouts = MIN(v, MAX_SYNCNT); > > + v = read_file_integer(RTO_MAX_MS, RTO_MAX_MS_DEFAULT); > + c->tcp.rto_max = MIN(DIV_ROUND_CLOSEST(v, 1000), INT_MAX);

Possibly we should verify this is => RTO_INIT.

As a sanity check, maybe, but I don't see any harmful effect if it's < RTO_INIT, right? So I'm not sure if we should. No preference from my side really.

Sorry, describing this as >= RTO_INIT was misleading. What I'm concerned about here is if the kernel value is set to 400ms, we'll round it to... 0s.

So, really what I'm concerned about is that we ensure this is > 0.

That's a good point.

Actually, thinking about it, I wonder if makes more sense to always round up to 1s, rather than to the nearest 1s.

So it's to replace DIV_ROUND_CLOSEST with DIV_ROUND_UP, right?

Yes. -- 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