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| author | Xin Hao <xhao@linux.alibaba.com> | 2023-05-31 17:58:17 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-06-09 16:25:51 -0700 |
| commit | 16618670276a77480e274117992cec5e42ce66a9 (patch) | |
| tree | f9cccd496b940ec7dd06bc118471e2036d208471 /mm/khugepaged.c | |
| parent | 3b11edf1f2398cac206a224308de6628ebeea924 (diff) | |
| download | lwn-16618670276a77480e274117992cec5e42ce66a9.tar.gz lwn-16618670276a77480e274117992cec5e42ce66a9.zip | |
mm: khugepaged: avoid pointless allocation for "struct mm_slot"
In __khugepaged_enter(), if "mm->flags" with MMF_VM_HUGEPAGE bit is set,
the "mm_slot" will be released and return, so we can call mm_slot_alloc()
after test_and_set_bit().
Link: https://lkml.kernel.org/r/20230531095817.11012-1-xhao@linux.alibaba.com
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: Andrew Morton <akpm@linux-foudation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/khugepaged.c')
| -rw-r--r-- | mm/khugepaged.c | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 6b9d39d65b73..3649ba12a235 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -422,19 +422,17 @@ void __khugepaged_enter(struct mm_struct *mm) struct mm_slot *slot; int wakeup; + /* __khugepaged_exit() must not run from under us */ + VM_BUG_ON_MM(hpage_collapse_test_exit(mm), mm); + if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) + return; + mm_slot = mm_slot_alloc(mm_slot_cache); if (!mm_slot) return; slot = &mm_slot->slot; - /* __khugepaged_exit() must not run from under us */ - VM_BUG_ON_MM(hpage_collapse_test_exit(mm), mm); - if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) { - mm_slot_free(mm_slot_cache, mm_slot); - return; - } - spin_lock(&khugepaged_mm_lock); mm_slot_insert(mm_slots_hash, mm, slot); /* |