lkml.org 
[lkml]   [2022]   [Jan]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH RFC v2 9/9] mm/huge_memory: remove stale locking logic from __split_huge_pmd()
Date
Let's remove the stale logic that was required for reuse_swap_page().

Signed-off-by: David Hildenbrand <david@redhat.com>
---
mm/huge_memory.c | 32 +-------------------------------
1 file changed, 1 insertion(+), 31 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 863c933b3b1e..5cc438f92548 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2158,8 +2158,6 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
{
spinlock_t *ptl;
struct mmu_notifier_range range;
- bool do_unlock_page = false;
- pmd_t _pmd;

mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
address & HPAGE_PMD_MASK,
@@ -2178,35 +2176,9 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
goto out;
}

-repeat:
if (pmd_trans_huge(*pmd)) {
- if (!page) {
+ if (!page)
page = pmd_page(*pmd);
- /*
- * An anonymous page must be locked, to ensure that a
- * concurrent reuse_swap_page() sees stable mapcount;
- * but reuse_swap_page() is not used on shmem or file,
- * and page lock must not be taken when zap_pmd_range()
- * calls __split_huge_pmd() while i_mmap_lock is held.
- */
- if (PageAnon(page)) {
- if (unlikely(!trylock_page(page))) {
- get_page(page);
- _pmd = *pmd;
- spin_unlock(ptl);
- lock_page(page);
- spin_lock(ptl);
- if (unlikely(!pmd_same(*pmd, _pmd))) {
- unlock_page(page);
- put_page(page);
- page = NULL;
- goto repeat;
- }
- put_page(page);
- }
- do_unlock_page = true;
- }
- }
if (PageMlocked(page))
clear_page_mlock(page);
} else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd)))
@@ -2214,8 +2186,6 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
__split_huge_pmd_locked(vma, pmd, range.start, freeze);
out:
spin_unlock(ptl);
- if (do_unlock_page)
- unlock_page(page);
/*
* No need to double call mmu_notifier->invalidate_range() callback.
* They are 3 cases to consider inside __split_huge_pmd_locked():
--
2.34.1
\
 
 \ /
  Last update: 2022-01-26 11:01    [W:0.172 / U:0.200 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site