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mm/hugetlb: avoid calculating fault_mutex_hash in truncate_op case

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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>
This commit is contained in:
Miaohe Lin 2021-05-04 18:33:34 -07:00 committed by Linus Torvalds
parent d83e6c8a9b
commit d4241a049a
1 changed files with 2 additions and 2 deletions
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4
fs/hugetlbfs/inode.c
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@ -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]);
}