Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1203769

Re: [PATCH] net: Unbreak resetting default values for tcp_wmem/udp_wmem_min

Show all headers | View raw

From: Calvin Owens <calvinowens@fb.com>
Date: Wed, 5 Aug 2015 13:26:54 -0700

> Commit 8133534c760d4083 ("net: limit tcp/udp rmem/wmem to
> SOCK_{RCV,SND}BUF_MIN") modified four sysctls to enforce that the values
> written to them are not less than SOCK_MIN_{RCV,SND}BUF.
> 
> This change is fine for tcp_rmem and udp_rmem_min, since SOCK_MIN_RCVBUF
> is equal to equal to TCP_SKB_MIN_TRUESIZE. But it breaks tcp_wmem and
> udp_wmem_min for previously valid values because SOCK_MIN_SNDBUF is
> (2 * TCP_SKB_MIN_TRUESIZE), which ends up being greater than 4KB.
> 
> Thus, 4096 is no longer accepted as a valid value, despite still being
> the default for udp_wmem_min, and for 'min' in tcp_wmem. A huge number
> of sysctl configurations at FB use 4096 as 'min', so this change breaks
> all of them.
> 
> This patch changes the sysctls to simply enforce that the value written
> is greater than or equal to the default value of SK_MEM_QUANTUM.
> 
> Fixes: 8133534c760d4083 ("net: limit tcp/udp rmem/wmem to SOCK_MIN...")
> Signed-off-by: Calvin Owens <calvinowens@fb.com>

I think increasing the default makes more sense.

If we don't allow applications to set 4K, the kernel shouldn't start
with that value either.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH] net: Unbreak resetting default values for tcp_wmem/udp_wmem_min Calvin Owens <calvinowens@fb.com> - 2015-08-05 22:30 +0200
  Re: [PATCH] net: Unbreak resetting default values for  tcp_wmem/udp_wmem_min David Miller <davem@davemloft.net> - 2015-08-10 07:50 +0200
    Re: [PATCH] net: Unbreak resetting default values for  tcp_wmem/udp_wmem_min Calvin Owens <calvinowens@fb.com> - 2015-08-11 05:40 +0200
      Re: [PATCH] net: Unbreak resetting default values for  tcp_wmem/udp_wmem_min David Miller <davem@davemloft.net> - 2015-08-11 05:50 +0200
        [PATCH] net: Use SK_MEM_QUANTUM as minimum for tcp/udp rmem/wmem Calvin Owens <calvinowens@fb.com> - 2015-08-12 07:00 +0200
          Re: [PATCH] net: Use SK_MEM_QUANTUM as minimum for tcp/udp rmem/wmem Eric Dumazet <eric.dumazet@gmail.com> - 2015-08-12 16:30 +0200
            Re: [PATCH] net: Use SK_MEM_QUANTUM as minimum for tcp/udp rmem/wmem Sorin Dumitru <sorin@returnze.ro> - 2015-08-12 19:10 +0200
              Re: [PATCH] net: Use SK_MEM_QUANTUM as minimum for tcp/udp rmem/wmem Eric Dumazet <eric.dumazet@gmail.com> - 2015-08-12 19:50 +0200
                Re: [PATCH] net: Use SK_MEM_QUANTUM as minimum for tcp/udp rmem/wmem Calvin Owens <calvinowens@fb.com> - 2015-08-13 23:10 +0200
          [PATCH] Revert "net: limit tcp/udp rmem/wmem to  SOCK_{RCV,SND}BUF_MIN" Calvin Owens <calvinowens@fb.com> - 2015-08-13 23:30 +0200
            Re: [PATCH] Revert "net: limit tcp/udp rmem/wmem to  SOCK_{RCV,SND}BUF_MIN" Eric Dumazet <eric.dumazet@gmail.com> - 2015-08-14 01:00 +0200
            Re: [PATCH] Revert "net: limit tcp/udp rmem/wmem to  SOCK_{RCV,SND}BUF_MIN" David Miller <davem@davemloft.net> - 2015-08-17 21:20 +0200

csiph-web