On Wed, Nov 9, 2011 at 3:41 PM, Jeff Mahoney
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virtual memory (kbytes, -v) 29536000
... but here is your problem.
I disagree. With the switches I used, and with sysctl -w vm.overcommit_memory=0 # or 1 according to the link I posted http://www.mjmwired.net/kernel/Documentation/vm/overcommit-accounting the cost of allocation with these parameters should be 0, and the call mmap((void *) NULL, someSize * (((size_t) 1) << 30), PROT_NONE, MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE, -1, 0); # someSize is integer with number of Gigs should succeed no matter what virtual memory, and no matter what size I am allocating. So far I have no other explanation then this is a bug (anyone agrees?). On the chrome list, people indicated same issue was fixed in Ubuntu lately (mmap 84Gb succeds with way less virtual memory). I only have 4 boxes with Opensuse ... will also try Opensuse 12.1 and report thanks, milan
- -Jeff
let me know if i should run anything else, thanks
On my 11.4 64-bit system, I can't reproduce your failure. I see:
jeffm@sled2:~> ./a.out Hello world Allocating 29Gb... Success: 0x7f7f79e57000 jeffm@sled2:~> uname -a Linux sled2 2.6.37.6-0.9-desktop #1 SMP PREEMPT 2011-10-19 22:33:27 +0200 x86_64 x86_64 x86_64 GNU/Linux
-Jeff
I am trying to resolve a failure of Google Native Client in Opensuse 64 11.4, discussed in Google Native Client forum:
[1] https://groups.google.com/forum/#!topic/native-client-discuss/7DUFfi_BxqM
To repeat the issue in a nutshell::
---------------------------------------------
Google native client (Chrome) works on recent versions of at least Ubuntu [1], but fails on Opensuse 11.4 (with all latest updates up to Nov 4). This failure can be reproduced in chrome 14, 15, 16 (from http://dl.google.com/linux/chrome/rpm/stable/x86_64) and verified by loading
[2] http://www.gonacl.com/dev/demos/sdk_examples/load_progress/load_progress.htm...
The problem / question for opensuse (kernel?) ::
------------------------------------------------------------------
There is a long discussion in the above thread, to get to the
point quickly: The Google guys identified an issue with mmap() with MAP_NORESERVE (see below). They believe it may be a bug or a kernel configuration issue(?)
A Chrome Nacl person suggest the following code should print "Success" but it fails in my testing:
#include
#include int main(void) { void *addr;
printf("Hello world\nAllocating 29Gb...\n"); addr = mmap((void *) NULL, 29 * (((size_t) 1) << 30), PROT_NONE, MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE, -1, 0); /* test 29 or other values */ if (MAP_FAILED == addr) { printf("FAILED\n"); } else { printf("Success: %p\n", addr); } return 0; }
This prints FAILED on Opensuse 11.4 64 bit.
I did some experiments. On my system:
# cat /proc/meminfo MemTotal: 15948428 kB MemFree: 11270612 kB .... CommitLimit: 28945728 kB Committed_AS: 4918284 kB ...
From running the test program above, it looks like *CommitLimit* is clearly used as upper limit of mmap(MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE), *no matter what vm.overcommit_memory* flag is used.
In concrete terms:
mmap((void *) NULL, 29 * (((size_t) 1) << 30), PROT_NONE, MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE, -1, 0); // always FAILS with value of 29 or higher
mmap((void *) NULL, 28 * (((size_t) 1) << 30), PROT_NONE, MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE, -1, 0); // always SUCCEEDS with value of 28 or lower
No matter what setting of sysctl -w vm.overcommit_memory=0 # or 1 or 2
(This seems a Opensuse 11.4 bug in modes 0 and 1, as according to [2] anonymous private readonly should have 0 cost)
Any comments or solutions or how to fix this?
Thanks,
Milan
[1] http://www.mjmwired.net/kernel/Documentation/filesystems/proc.txt
[2]
http://www.mjmwired.net/kernel/Documentation/vm/overcommit-accounting
======================= PS: I am attaching a few pieces of info
about my system that may be relevant:
The hardware is AMD 4 core AMD Athlon II X4 610e and has 16Gb (sixteen) of memory, running very little (just KDE desktop at this point)
# swapon -s Filename Type Size Used Priority /dev/sda1 partition 20971516 0 -1
# cat /proc/sys/vm/overcommit_memory 0
# ulimit -a core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 123980 max locked memory (kbytes, -l) 64 max memory size (kbytes, -m) 13556224 open files (-n) 1024 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 123980 virtual memory (kbytes, -v) 29536000 file locks (-x) unlimited
# df Filesystem 1K-blocks Used Available Use% Mounted on rootfs 82567856 15558248 62815408 20% / devtmpfs 7934744 244 7934500 1% /dev tmpfs 7974212 1592 7972620 1% /dev/shm /dev/sda2 82567856 15558248 62815408 20% / /dev/sda3 377510440 90623252 267710692 26% /home
- -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
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