[LU-16609] top_trans_create() can oom due to the gfp flags

• Status: Resolved
• Project: Lustre
• Fix Version/s: Lustre 2.16.0
• Type: Bug
• Priority: Major
• Reporter: Andrew Perepechko
• Assignee: Andrew Perepechko
• Resolution: Fixed
• Labels: patch
• Severity: 3

Description

top_trans_create() requests __GFP_IO memory allocation,
which does not allow direct reclaim. However, if the
memory shortage is temporary, direct reclaim is reasonable.

GFP_NOFS is __GFP_IO with some additional reclaim bits.

Comments

[Gerrit Updater]

"Andrew Perepechko <[e-mail]>" uploaded a new patch: https://review.whamcloud.com/c/fs/lustre-release/+/50176
Subject: LU-16609 target: top_trans_create cannot alloc memory
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 909bf5257eb33fe45071cf52f7a00ccf3fb72e12

[Andrew Perepechko]

__GFP_IO alone does not make sense because this bit is only used by the memory reclaimer, so we need explicitly to specify that we want memory reclaim (bound by __GFP_IO, of course):

 

#define GFP_NOFS        (__GFP_RECLAIM | __GFP_IO)

#define __GFP_RECLAIM ((force gfp_t)(_GFP_DIRECT_RECLAIM|_GFP_KSWAPD_RECLAIM))

[Gerrit Updater]

"Oleg Drokin <[e-mail]>" merged in patch https://review.whamcloud.com/c/fs/lustre-release/+/50176/
Subject: LU-16609 target: top_trans_create cannot alloc memory
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 9d1f8f1e3557ee3349c623f4f5596df44f60b082

[Peter Jones]

Landed for 2.16