code review 6997049: runtime/linux: die more gracefully when locked mem quot...

runtime/linux: die more gracefully when locked mem quota is overrun.

Used to then die on a nil pointer situation. Most Linux standard setups are rather restrictive regarding the default amount of lockable memory.

[Sebastien Paolacci, 2012-12-23 10:16:12]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://code.google.com/p/go/

[minux1, 2012-12-23 13:35:22]

https://codereview.appspot.com/6997049/diff/2002/src/pkg/runtime/mem_linux.c
File src/pkg/runtime/mem_linux.c (right):

https://codereview.appspot.com/6997049/diff/2002/src/pkg/runtime/mem_linux.c#...
src/pkg/runtime/mem_linux.c:68: runtime·printf("runtime: mmap: too much locked
memory (check rlimits).\n");
check 'ulimit -l'?

[rsc, 2012-12-23 19:22:02]

How can this happen?

[Sebastien Paolacci, 2012-12-23 19:52:28]

On 2012/12/23 19:22:02, rsc wrote:
> How can this happen?

For exemple, by using `syscall.Mlockall(syscall.MCL_FUTURE)' with an
under-provisioned enough "ulimit -l". That's (at least) what happened to me.

mmap's describe the situation as "EAGAIN: The file has been locked, or too much
memory has been locked". I can't really get why they choose that error code, but
it really does happen..

Sebastien

[Sebastien Paolacci, 2012-12-23 19:56:08]

https://codereview.appspot.com/6997049/diff/2002/src/pkg/runtime/mem_linux.c
File src/pkg/runtime/mem_linux.c (right):

https://codereview.appspot.com/6997049/diff/2002/src/pkg/runtime/mem_linux.c#...
src/pkg/runtime/mem_linux.c:68: runtime·printf("runtime: mmap: too much locked
memory (check rlimits).\n");
On 2012/12/23 13:35:22, minux wrote:
> check 'ulimit -l'?

Done.

[minux1, 2012-12-23 19:59:58]

LGTM.
Will wait for Russ's comment.

[rsc, 2012-12-29 19:25:52]

LGTM

[rsc, 2012-12-30 02:36:03]

Submitted but hg didn't manage to send mail about it.
You may need to run hg change -D 6997049 after hg sync.

[gobot, 2013-12-20 16:21:42]

Replacing golang-dev with golang-codereviews.

[dave_cheney.net, 2014-01-31 00:42:56]

On 2013/12/20 16:21:42, gobot wrote:
> Replacing golang-dev with golang-codereviews.

R=close