The patch titled
Subject: mm/hugeltb: clarify (chg - freed) won't go negative in hugetlb_unreserve_pages()
has been removed from the -mm tree. Its filename was
mm-hugeltb-clarify-chg-freed-wont-go-negative-in-hugetlb_unreserve_pages.patch
This patch was dropped because it was merged into mainline or a subsystem tree
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From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/hugeltb: clarify (chg - freed) won't go negative in hugetlb_unreserve_pages()
The resv_map could be NULL since this routine can be called in the evict
inode path for all hugetlbfs inodes and we will have chg = 0 in this case.
But (chg - freed) won't go negative as Mike pointed out:
"If resv_map is NULL, then no hugetlb pages can be allocated/associated
with the file. As a result, remove_inode_hugepages will never find any
huge pages associated with the inode and the passed value 'freed' will
always be zero."
Add a comment clarifying this to make it clear and also avoid confusion.
Link: https://lkml.kernel.org/r/20210410072348.20437-4-linmiaohe@xxxxxxxxxx
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Feilong Lin <linfeilong@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 3 +++
1 file changed, 3 insertions(+)
--- a/mm/hugetlb.c~mm-hugeltb-clarify-chg-freed-wont-go-negative-in-hugetlb_unreserve_pages
+++ a/mm/hugetlb.c
@@ -5267,6 +5267,9 @@ long hugetlb_unreserve_pages(struct inod
/*
* If the subpool has a minimum size, the number of global
* reservations to be released may be adjusted.
+ *
+ * Note that !resv_map implies freed == 0. So (chg - freed)
+ * won't go negative.
*/
gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
hugetlb_acct_memory(h, -gbl_reserve);
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
