Re: git: 7146ad04f18e - main - tcp: refactor tcp_autosndbuf() and associated sysctls

On 22 Oct 2026, at 11:29, Kristof Provost wrote:
> On 22 Oct 2026, at 5:31, Gleb Smirnoff wrote:
>> The branch main has been updated by glebius:
>>
>> URL: 
>> https://cgit.FreeBSD.org/src/commit/?id=7146ad04f18e7f0767a4d44cff43c1c67ea98cec
>>
>> commit 7146ad04f18e7f0767a4d44cff43c1c67ea98cec
>> Author:     Gleb Smirnoff <glebius@FreeBSD.org>
>> AuthorDate: 2026-10-22 03:27:47 +0000
>> Commit:     Gleb Smirnoff <glebius@FreeBSD.org>
>> CommitDate: 2026-10-22 03:27:47 +0000
>>
>>     tcp: refactor tcp_autosndbuf() and associated sysctls
>>
>>     Rename tcp_sndbuf_autoscale() to tcp_autosndbuf().  This matches
>>     complementary tcp_autorcvbuf() that was factored out as a 
>> separate
>>     function a few months before tcp_sndbuf_autoscale() was.  Move 
>> the large
>>     comment to the header of the function.  Use unsigned types for 
>> all sizing
>>     sysctls and variables and use bool for the switching sysctl.  Add 
>> a
>>     comment above net.inet.tcp.sendbuf_auto_lowat (default to off) 
>> providing a
>>     reference to its origins.  Add DTrace probe tcp::send-autoresize,
>>     complementary to the existing tcp::receive-autoresize.
>>
>>     Rack has its own function, just enable the DTrace probe there.
>>
>>     Reviewed by:            tuexen
>>     Differential Revision:  https://reviews.freebsd.org/D60732
>> ---
>>  sys/netinet/in_kdtrace.c      |   4 ++
>>  sys/netinet/in_kdtrace.h      |   1 +
>>  sys/netinet/tcp_output.c      | 142 
>> +++++++++++++++++++++---------------------
>>  sys/netinet/tcp_stacks/bbr.c  |   2 +-
>>  sys/netinet/tcp_stacks/rack.c |   5 +-
>>  sys/netinet/tcp_var.h         |  10 +--
>>  6 files changed, 85 insertions(+), 79 deletions(-)
>>
> …
>> index 09295544855f..d11a2b745382 100644
>> --- a/sys/netinet/tcp_output.c
>> +++ b/sys/netinet/tcp_output.c
> …
>>  void
>> -tcp_sndbuf_autoscale(struct tcpcb *tp, struct socket *so, uint32_t 
>> sendwin)
>> +tcp_autosndbuf(struct tcpcb *tp, u_int sendwin)
>>  {
>>
> …
>> +	SOCK_RECVBUF_LOCK_ASSERT(so);
>> +
> Is this assert right? I’d think autosndbuf is about the send buffer, 
> not the receive buffer.
>
With this patch the system does just work for me:

	diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c
	index d11a2b745382..b5f36d83f5a2 100644
	--- a/sys/netinet/tcp_output.c
	+++ b/sys/netinet/tcp_output.c
	@@ -2154,7 +2154,7 @@ tcp_autosndbuf(struct tcpcb *tp, u_int sendwin)
	        struct socket *so = tptosocket(tp);
	        u_int lowat, newsize;

	-       SOCK_RECVBUF_LOCK_ASSERT(so);
	+       SOCK_SENDBUF_LOCK_ASSERT(so);

	        if (!V_tcp_do_autosndbuf || (so->so_snd.sb_flags & SB_AUTOSIZE) 
== 0)
	                return;

—
Kristof