Bug 7026 - Don't use ALLOC_CMA in long term gup path
Summary: Don't use ALLOC_CMA in long term gup path
Status: NEW
Alias: None
Product: ANCK 5.10 Dev
Classification: ANCK
Component: mm (show other bugs) mm
Version: unspecified
Hardware: All Linux
: P3-Medium S3-normal
Target Milestone: ---
Assignee: wangrongwei
QA Contact: shuming
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Reported: 2023-10-20 16:46 UTC by jiangxin00
Modified: 2023-10-20 17:23 UTC (History)
2 users (show)

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Description jiangxin00 hygon_group 2023-10-20 16:46:16 UTC 
Description of problem:
When user allocates massive amounts of pages using long term gup,
__compaction_suitable() routine may return COMPACT_CONTINUE and
enter direct reclaim path with high probability. As a result, the
high direct reclaim latency makes memory allocation very slow.
In the scenario that migration source pages are longterm pinned
and these pages cannot be migrated to CMA regions, it is unresonable
to return COMPACT_CONTINUE in __compaction_suitable() routine.

This patch simply removes ALLOC_CMA in __compaction_suitable()
routine in long term gup path to avoid the issue.

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Comment 1 小龙 admin 2023-10-20 17:23:59 UTC 
The PR Link: https://gitee.com/anolis/cloud-kernel/pulls/2321