[Bugme-new] [Bug 10991] New: linux 2.6.25 (32 bits): tcp_mem calculation wrong ?
bugme-daemon at bugzilla.kernel.org
bugme-daemon at bugzilla.kernel.org
Thu Jun 26 14:56:23 PDT 2008
http://bugzilla.kernel.org/show_bug.cgi?id=10991
Summary: linux 2.6.25 (32 bits): tcp_mem calculation wrong ?
Product: Networking
Version: 2.5
KernelVersion: 2.6.25.7
Platform: All
OS/Version: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: IPV4
AssignedTo: shemminger at linux-foundation.org
ReportedBy: miquels at cistron.nl
Latest working kernel version: 2.6.11.12
Earliest failing kernel version: 2.6.25.7
Distribution: debian
Hardware Environment: i386 32 bit 8 GB RAM
Software Environment:
Problem Description: kernel goes OOM with lots of sockets and traffic
(latest working / earliest failing might be different, these
were the versions I used)
I started upgrading a bunch of machines in my nntp server farm
to a recent kernel- 2.6.25.x. They were running 2.6.11.12 on
32 bits, and I upgraded them to 2.6.25.x on 64 bits.
All went fine until I noticed a few machines didn't have a 64
bit capable processor, so I had to keep them on a 32 bit kernel.
These are machines with dual xeons 3 Ghz and 8 GB of RAM.
On the 32 bit machines I keep getting the error below, and a flood
of these on a 9600 baud serial console essentially kills the machine:
diablo invoked oom-killer: gfp_mask=0xd0, order=0, oomkilladj=0
Pid: 4459, comm: diablo Not tainted 2.6.25.7-rc1 #1
[<c0249660>] oom_kill_process+0x120/0x210
[<c0227ff8>] __capable+0x8/0x20
[<c0249898>] badness+0x128/0x1c0
[<c0249b1c>] out_of_memory+0x17c/0x1c0
[<c024bdf4>] __alloc_pages+0x254/0x350
[<c03b75ad>] tcp_sendmsg+0x5cd/0xb50
[<c0381672>] sock_aio_write+0xe2/0x100
[<c02681e7>] do_sync_write+0xc7/0x110
[<c0232f20>] autoremove_wake_function+0x0/0x50
[<c0268af3>] vfs_write+0x133/0x140
[<c0269131>] sys_write+0x41/0x70
[<c0202e5e>] syscall_call+0x7/0xb
After some investigation, I found out that the values of
/proc/sys/net/ipv4/tcp_mem are quite different between
these two versions:
2.6.11.12:
$ cat tcp_mem
98304 131072 196608
2.6.25:
# cat tcp_mem
804672 1072896 1609344
Somwehere between 2.6.11.12 and 2.6.25, the calculation method of
the tcp_mem array was changed. Now 1609344 pages is 6.5 GB,
and that will ofcourse never fit in x86_32's low memory ..
I posted this bug, and a patch, to the kernel and the netdev
mailinglists, but got no reaction. So I'm filing it here.
See:
[PATCH] tcp.c: calculate tcp_mem based on low memory instead of all memory
http://marc.info/?t=121380308200001&r=1&w=2
tcp_mem calculation wrong on x86_32 ?
http://marc.info/?l=linux-netdev&m=121362441431941&w=2
--
Configure bugmail: http://bugzilla.kernel.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.
More information about the Bugme-new
mailing list