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authorMiaohe Lin <linmiaohe@huawei.com>2021-05-04 18:33:34 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-05-05 11:27:20 -0700
commitd4241a049ac0049fe96b3dae0598092517dbf6bd (patch)
tree17a9a6758bcb4f3cc25e1b31712a548c8bcfc7bc
parentd83e6c8a9b65876b0dcd11ca25e8c39bd7bb1a1c (diff)
downloadlinux-d4241a049ac0049fe96b3dae0598092517dbf6bd.tar.bz2
mm/hugetlb: avoid calculating fault_mutex_hash in truncate_op case
The fault_mutex hashing overhead can be avoided in truncate_op case because page faults can not race with truncation in this routine. So calculate hash for fault_mutex only in !truncate_op case to save some cpu cycles. Link: https://lkml.kernel.org/r/20210308112809.26107-6-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/hugetlbfs/inode.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index c262566f7c5d..d81f52b87bd7 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -482,10 +482,9 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
for (i = 0; i < pagevec_count(&pvec); ++i) {
struct page *page = pvec.pages[i];
- u32 hash;
+ u32 hash = 0;
index = page->index;
- hash = hugetlb_fault_mutex_hash(mapping, index);
if (!truncate_op) {
/*
* Only need to hold the fault mutex in the
@@ -493,6 +492,7 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
* page faults. Races are not possible in the
* case of truncation.
*/
+ hash = hugetlb_fault_mutex_hash(mapping, index);
mutex_lock(&hugetlb_fault_mutex_table[hash]);
}