On Tue, Feb 07, 2017 at 07:30:54PM +0900, Tetsuo Handa wrote:

Brian Foster wrote:

quoted

quoted

The workload is to write to a single file on XFS from 10 processes demonstrated at
http://lkml.kernel.org/r/201512052133.IAE00551.LSOQFtMFFVOHOJ@I-love.SAKURA.ne.jp
using "while :; do ./oom-write; done" loop on a VM with 4CPUs / 2048MB RAM.
With this XFS_FILBLKS_MIN() change applied, I no longer hit assertion failures.

Thanks for testing. Well, that's an interesting workload. I couldn't
reproduce on a few quick tries in a similarly configured vm.

It takes 10 to 15 minutes. Maybe some size threshold involved?

quoted

/tmp/file _is_ on an XFS filesystem in your test, correct? If so and if
you still have the output file from a test that reproduced, could you
get the 'xfs_io -c "fiemap -v" <file>' output?

Here it is.

[  720.199748] 0 pages HighMem/MovableOnly
[  720.199749] 150524 pages reserved
[  720.199749] 0 pages cma reserved
[  720.199750] 0 pages hwpoisoned
[  722.187335] XFS: Assertion failed: oldlen > newlen, file: fs/xfs/libxfs/xfs_bmap.c, line: 2867
[  722.201784] ------------[ cut here ]------------

...

# ls -l /tmp/file
-rw------- 1 kumaneko kumaneko 43426648064 Feb  7 19:25 /tmp/file
# xfs_io -c "fiemap -v" /tmp/file
/tmp/file:
 EXT: FILE-OFFSET          BLOCK-RANGE            TOTAL FLAGS
   0: [0..262015]:         358739712..359001727  262016   0x0

...

 187: [84810808..84901119]: 110211736..110302047   90312   0x1

Ok, from the size of the file I realized that I missed you were running
in a loop the first time around. I tried playing with it some more and
still haven't been able to reproduce.

Anyways, the patch intended to fix this has been reviewed[1] and queued
for the next release, so it's probably not a big deal since you've
already verified it. Thanks again.

Brian

[1] http://www.spinics.net/lists/linux-xfs/msg04083.html

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>