Hi Dave,
Thanks for your reply.
----- 原始邮件 -----
> 发件人: "Dave Chinner" <david@xxxxxxxxxxxxx>
> 收件人: "Zorro Lang" <zlang@xxxxxxxxxx>
> 抄送: fstests@xxxxxxxxxxxxxxx, eguan@xxxxxxxxxx
> 发送时间: 星期一, 2015年 8 月 17日 上午 8:03:36
> 主题: Re: [PATCH] generic/084: check inotify limit before tail many files
>
> On Fri, Aug 14, 2015 at 12:16:32AM +0800, Zorro Lang wrote:
> > generic/084 try to run 'tail' command, tail will use
> > inotify, and there're some limit about inotify. I think
> > the most important is fs.inotify.max_user_instances, then
> > fs.inotify.max_user_watches is importand too.
> >
> > When I test on a machine with 154 cpu cores, this case
> > run failed, and hit many warning likes:
> >
> > tail: inotify cannot be used, reverting to polling: Too many
> > open files
> >
> > Because the fs.inotify.max_user_instances is 128, so if
> > we try to tail 154 files, it will be failed.
>
> We use 'tail' all over the place in xfstests, so why is only
> generic/084 affected?
Because generic/084 use try to create $nr_cpu tail processes:
for i in `seq 1 $nr_cpu`; do
...
tail -f $testfile &
...
done
And nr_cpu=`$here/src/feature -o`.
Generally fs.inotify.max_user_instances is 128, when a machine
have more than(or nearly the same) this number, this test will
failed.
Maybe other cases don't try to create so many tail processes, so
they passed.
>
> And really, this seems more like a distro/environment bug and
> doesn't need xfstests help to work around. i.e. changing the
> sysctl before starting xfstests seems much more appropriate than
> hacking it a random test. Especially as there may be more than one
> test that is affected by this, and when run in a random order this
> would cause those other tests to pass/fail depending on whether
> generic/084 had already been run on that machine....
As this situation generally won't effect other cases, so I try to
make the patch don't effect more other cases. Because I don't know
if someone try to test fs.inotify...
But if maintainer think it'll be better, I will change the patch:)
Thanks,
Zorro Lang
>
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@xxxxxxxxxxxxx
>
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