The patch titled
Subject: hugetlb: remove unnecessary set_page_count in prep_compound_gigantic_page
has been added to the -mm tree. Its filename is
hugetlb-remove-unnecessary-set_page_count-in-prep_compound_gigantic_page.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/hugetlb-remove-unnecessary-set_page_count-in-prep_compound_gigantic_page.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/hugetlb-remove-unnecessary-set_page_count-in-prep_compound_gigantic_page.patch
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------------------------------------------------------
From: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Subject: hugetlb: remove unnecessary set_page_count in prep_compound_gigantic_page
In commit 7118fc2906e29 ("hugetlb: address ref count racing in
prep_compound_gigantic_page"), page_ref_freeze is used to atomically zero
the ref count of tail pages iff they are 1. The unconditional call to
set_page_count(0) was left in the code. This call is after
page_ref_freeze so it is really a noop.
Remove redundant and unnecessary set_page_count call.
Link: https://lkml.kernel.org/r/20211026220635.35187-1-mike.kravetz@xxxxxxxxxx
Fixes: 7118fc2906e29 ("hugetlb: address ref count racing in prep_compound_gigantic_page")
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Suggested-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Reviewed-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 1 -
1 file changed, 1 deletion(-)
--- a/mm/hugetlb.c~hugetlb-remove-unnecessary-set_page_count-in-prep_compound_gigantic_page
+++ a/mm/hugetlb.c
@@ -1792,7 +1792,6 @@ static bool __prep_compound_gigantic_pag
} else {
VM_BUG_ON_PAGE(page_count(p), p);
}
- set_page_count(p, 0);
set_compound_head(p, page);
}
atomic_set(compound_mapcount_ptr(page), -1);
_
Patches currently in -mm which might be from mike.kravetz@xxxxxxxxxx are
hugetlb-add-demote-hugetlb-page-sysfs-interfaces.patch
hugetlb-add-demote-hugetlb-page-sysfs-interfaces-fix.patch
mm-cma-add-cma_pages_valid-to-determine-if-pages-are-in-cma.patch
hugetlb-be-sure-to-free-demoted-cma-pages-to-cma.patch
hugetlb-add-demote-bool-to-gigantic-page-routines.patch
hugetlb-add-hugetlb-demote-page-support.patch
hugetlb-add-hugetlb-demote-page-support-v4.patch
hugetlb-remove-unnecessary-set_page_count-in-prep_compound_gigantic_page.patch
