https://github.com/torvalds/linux
Revision 5d37852bf7d48e5afb5238a658cc167e7b78b381 authored by Calvin Owens on 13 August 2015, 21:21:34 UTC, committed by David S. Miller on 17 August 2015, 19:10:30 UTC
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. That change causes 4096 to no longer be accepted as a valid value for 'min' in tcp_wmem and udp_wmem_min. 4096 has been the default for both of those sysctls for a long time, and unfortunately seems to be an extremely popular setting. This change breaks a large number of sysctl configurations at Facebook. That commit referred to b1cb59cf2efe7971 ("net: sysctl_net_core: check SNDBUF and RCVBUF for min length"), which choose to use the SOCK_MIN constants as the lower limits to avoid nasty bugs. But AFAICS, a limit of SOCK_MIN_SNDBUF isn't necessary to do that: the BUG_ON cited in the commit message seems to have happened because unix_stream_sendmsg() expects a minimum of a full page (ie SK_MEM_QUANTUM) and the math broke, not because it had less than SOCK_MIN_SNDBUF allocated. This particular issue doesn't seem to affect TCP however: using a setting of "1 1 1" for tcp_{r,w}mem works, although it's obviously suboptimal. SK_MEM_QUANTUM would be a nice minimum, but it's 64K on some archs, so there would still be breakage. Since a value of one doesn't seem to cause any problems, we can drop the minimum 8133534c added to fix this. This reverts commit 8133534c760d4083f79d2cde42c636ccc0b2792e. Fixes: 8133534c760d4083 ("net: limit tcp/udp rmem/wmem to SOCK_MIN...") Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Sorin Dumitru <sorin@returnze.ro> Signed-off-by: Calvin Owens <calvinowens@fb.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Tip revision: 5d37852bf7d48e5afb5238a658cc167e7b78b381 authored by Calvin Owens on 13 August 2015, 21:21:34 UTC
Revert "net: limit tcp/udp rmem/wmem to SOCK_{RCV,SND}BUF_MIN"
Revert "net: limit tcp/udp rmem/wmem to SOCK_{RCV,SND}BUF_MIN"
Tip revision: 5d37852
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include | ||
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net | ||
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.gitignore | -rw-r--r-- | 1.2 KB |
.mailmap | -rw-r--r-- | 5.3 KB |
COPYING | -rw-r--r-- | 18.3 KB |
CREDITS | -rw-r--r-- | 94.7 KB |
Kbuild | -rw-r--r-- | 2.6 KB |
Kconfig | -rw-r--r-- | 252 bytes |
MAINTAINERS | -rw-r--r-- | 313.7 KB |
Makefile | -rw-r--r-- | 53.3 KB |
README | -rw-r--r-- | 18.2 KB |
REPORTING-BUGS | -rw-r--r-- | 7.3 KB |
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