Ge Yang 344ef45b03 mm/hugetlb: remove unnecessary holding of hugetlb_lock
In isolate_or_dissolve_huge_folio(), after acquiring the hugetlb_lock, it
is only for the purpose of obtaining the correct hstate, which is then
passed to alloc_and_dissolve_hugetlb_folio().

alloc_and_dissolve_hugetlb_folio() itself also acquires the hugetlb_lock. 
We can have alloc_and_dissolve_hugetlb_folio() obtain the hstate by
itself, so that isolate_or_dissolve_huge_folio() no longer needs to
acquire the hugetlb_lock.  In addition, we keep the folio_test_hugetlb()
check within isolate_or_dissolve_huge_folio().  By doing so, we can avoid
disrupting the normal path by vainly holding the hugetlb_lock.

replace_free_hugepage_folios() has the same issue, and we should address
it as well.

Addresses a possible performance problem which was added by the hotfix
113ed54ad2 ("mm/hugetlb: fix kernel NULL pointer dereference when
replacing free hugetlb folios").

Link: https://lkml.kernel.org/r/1748317010-16272-1-git-send-email-yangge1116@126.com
Fixes: 113ed54ad2 ("mm/hugetlb: fix kernel NULL pointer dereference when replacing free hugetlb folios")
Signed-off-by: Ge Yang <yangge1116@126.com>
Suggested-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <21cnbao@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-06-25 15:55:03 -07:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2025-06-22 13:30:08 -07:00
2024-03-18 03:36:32 -06:00

Linux kernel
============

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