linux.git/mm/compaction.c, branch v5.19

mm, compaction: fast_find_migrateblock() should return pfn in the target zone

2022-05-13T23:48:57+00:00

At present, pages not in the target zone are added to cc->migratepages
list in isolate_migratepages_block().  As a result, pages may migrate
between nodes unintentionally.

This would be a serious problem for older kernels without commit
a984226f457f849e ("mm: memcontrol: remove the pgdata parameter of
mem_cgroup_page_lruvec"), because it can corrupt the lru list by
handling pages in list without holding proper lru_lock.

Avoid returning a pfn outside the target zone in the case that it is
not aligned with a pageblock boundary.  Otherwise
isolate_migratepages_block() will handle pages not in the target zone.

Link: https://lkml.kernel.org/r/20220511044300.4069-1-yamamoto.rei@jp.fujitsu.com
Fixes: 70b44595eafe ("mm, compaction: use free lists to quickly locate a migration source")
Signed-off-by: Rei Yamamoto 
Reviewed-by: Miaohe Lin 
Acked-by: Mel Gorman 
Reviewed-by: Oscar Salvador 
Cc: Don Dutile 
Cc: Wonhyuk Yang 
Cc: Rei Yamamoto 
Cc: 
Signed-off-by: Andrew Morton

tracing: incorrect gfp_t conversion

2022-05-13T14:20:18+00:00

Fixes the following sparse warnings:

include/trace/events/*: sparse: cast to restricted gfp_t
include/trace/events/*: sparse: restricted gfp_t degrades to integer

gfp_t type is bitwise and requires __force attributes for any casts.

Link: https://lkml.kernel.org/r/331d88fe-f4f7-657c-02a2-d977f15fbff6@openvz.org
Signed-off-by: Vasily Averin 
Cc: Steven Rostedt 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton

mm: compaction: make sure highest is above the min_pfn

2022-04-29T06:16:19+00:00

It's not guaranteed that highest will be above the min_pfn.  If highest is
below the min_pfn, migrate_pfn and free_pfn can meet prematurely and lead
to some useless work.  Make sure highest is above min_pfn to avoid making
a futile effort.

Link: https://lkml.kernel.org/r/20220418141253.24298-13-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Cc: Charan Teja Kalla 
Cc: David Hildenbrand 
Cc: Pintu Kumar 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm: compaction: simplify the code in __compact_finished

2022-04-29T06:16:19+00:00

Since commit efe771c7603b ("mm, compaction: always finish scanning of a
full pageblock"), compaction will always finish scanning a pageblock.  And
migrate_pfn is assured to align with pageblock_nr_pages when we reach
here.  So we will always return COMPACT_SUCCESS if a suitable fallback is
found due to the below IS_ALIGNED check of migrate_pfn.  Simplify the code
to make this clear and improve the readability.  No functional change
intended.

Link: https://lkml.kernel.org/r/20220418141253.24298-12-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Cc: Charan Teja Kalla 
Cc: David Hildenbrand 
Cc: Pintu Kumar 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm: compaction: make compaction_zonelist_suitable return false when COMPACT_SUCCESS

2022-04-29T06:16:18+00:00

When compact_result indicates that the allocation should now succeed, i.e.
compact_result = COMPACT_SUCCESS, compaction_zonelist_suitable should
return false because there is no need to do compaction now.

Link: https://lkml.kernel.org/r/20220418141253.24298-11-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Cc: Charan Teja Kalla 
Cc: David Hildenbrand 
Cc: Pintu Kumar 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm: compaction: avoid possible NULL pointer dereference in kcompactd_cpu_online

2022-04-29T06:16:18+00:00

It's possible that kcompactd_run could fail to run kcompactd for a hot
added node and leave pgdat->kcompactd as NULL.  So pgdat->kcompactd should
be checked here to avoid possible NULL pointer dereference.

Link: https://lkml.kernel.org/r/20220418141253.24298-10-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Cc: Charan Teja Kalla 
Cc: David Hildenbrand 
Cc: Pintu Kumar 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm: compaction: clean up comment about async compaction in isolate_migratepages

2022-04-29T06:16:18+00:00

Since commit 282722b0d258 ("mm, compaction: restrict async compaction to
pageblocks of same migratetype"), async direct compaction is restricted to
scan the pageblocks of same migratetype.  Correct the comment accordingly.

Link: https://lkml.kernel.org/r/20220418141253.24298-9-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Cc: Charan Teja Kalla 
Cc: David Hildenbrand 
Cc: Pintu Kumar 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm: compaction: use helper compound_nr in isolate_migratepages_block

2022-04-29T06:16:18+00:00

Use helper compound_nr to make use of compound_nr when CONFIG_64BIT and
simplify the code a bit.

Link: https://lkml.kernel.org/r/20220418141253.24298-8-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Cc: Charan Teja Kalla 
Cc: David Hildenbrand 
Cc: Pintu Kumar 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm: compaction: use COMPACT_CLUSTER_MAX in compaction.c

2022-04-29T06:16:18+00:00

Always use COMPACT_CLUSTER_MAX here as we're doing the compaction.  Minor
improvements in readability.

Link: https://lkml.kernel.org/r/20220418141253.24298-7-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Cc: Charan Teja Kalla 
Cc: David Hildenbrand 
Cc: Pintu Kumar 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm: compaction: clean up comment about suitable migration target recheck

2022-04-29T06:16:17+00:00

checked_pageblock is already removed and suitable_migration_target is not
rechecked under the zone lock since commit f8224aa5a0a4 ("mm, compaction:
do not recheck suitable_migration_target under lock").  Correct the
comment accordingly.

Link: https://lkml.kernel.org/r/20220418141253.24298-6-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Cc: Charan Teja Kalla 
Cc: David Hildenbrand 
Cc: Pintu Kumar 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton