[LTP] [RFC PATCH] fallocate05: increase the fallocate and defallocate size

[Ralph Siemsen]

Hello,

On Wed, Sep 22, 2021 at 04:32:45PM +0200, Cyril Hrubis wrote:
>>
>> That try one by one block after filling full of the FS because nobody knows
>> when fails.
>>
>> But as you suggested we can do that as well for the previous allocation :).
>>
>> So, will you create a patch, or I do that tomorrow?
>
>I will not manage today. So either you do it or I can do it tomorrow
>:-).

I tried making a patch for this, which I can share. But after testing, I 
am still seeing OOM. Upon further inspection, it seems to be coming from 
tst_fill_fs() function, when operating on a tmpfs.  I see the message:

tst_test.c:903: TINFO: Limiting tmpfs size to 512MB

However the machine only has 256MB total, of which at best 200 MB is 
available after kernel has booted.

I'm now a bit confused as to why fallocate05 test worked previously. 
With release 20210524 version, I see the following:

tst_test.c:1379: TINFO: Testing on tmpfs
tst_test.c:888: TINFO: Skipping mkfs for TMPFS filesystem
tst_test.c:1311: TINFO: Timeout per run is 0h 15m 00s
tst_fill_fs.c:32: TINFO: Creating file mntpoint/file0 size 21710183
tst_fill_fs.c:32: TINFO: Creating file mntpoint/file1 size 8070086
tst_fill_fs.c:32: TINFO: Creating file mntpoint/file2 size 3971177
tst_fill_fs.c:32: TINFO: Creating file mntpoint/file3 size 36915315
tst_fill_fs.c:32: TINFO: Creating file mntpoint/file4 size 70310993
tst_fill_fs.c:59: TINFO: write(): ENOSPC (28)
fallocate05.c:81: TPASS: write() wrote 65536 bytes
fallocate05.c:102: TINFO: fallocate()d 0 extra blocks on full FS
fallocate05.c:114: TPASS: fallocate() on full FS
fallocate05.c:130: TPASS: fallocate(FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE)
fallocate05.c:136: TPASS: write()

Whereas with the latest git version, it seems to create two more 
additional files, before OOM kicks in:

tst_test.c:1421: TINFO: Testing on tmpfs
tst_test.c:922: TINFO: Skipping mkfs for TMPFS filesystem
tst_test.c:903: TINFO: Limiting tmpfs size to 512MB
tst_test.c:1353: TINFO: Timeout per run is 0h 15m 00s
tst_fill_fs.c:32: TINFO: Creating file mntpoint/file0 size 21710183
tst_fill_fs.c:32: TINFO: Creating file mntpoint/file1 size 8070086
tst_fill_fs.c:32: TINFO: Creating file mntpoint/file2 size 3971177
tst_fill_fs.c:32: TINFO: Creating file mntpoint/file3 size 36915315
tst_fill_fs.c:32: TINFO: Creating file mntpoint/file4 size 70310993
tst_fill_fs.c:32: TINFO: Creating file mntpoint/file5 size 4807935
tst_fill_fs.c:32: TINFO: Creating file mntpoint/file6 size 90739786
<... OOM begins here ...>

Any thoughts on what might be happening?

Regards,
Ralph