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| author | Miaohe Lin <linmiaohe@huawei.com> | 2021-05-05 04:33:55 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-05-05 21:27:21 +0300 |
| commit | aaa9705b4af3608fd759c9ba8d0003f7a83fb335 (patch) | |
| tree | af5b7c4fc59812b273354957ac178695a154d763 /mm | |
| parent | 71f9e58eb408db423e0e27b55e0de66fb3590296 (diff) | |
| download | linux-aaa9705b4af3608fd759c9ba8d0003f7a83fb335.tar.xz | |
mm/huge_memory.c: make get_huge_zero_page() return bool
It's guaranteed that huge_zero_page will not be NULL if
huge_zero_refcount is increased successfully.
When READ_ONCE(huge_zero_page) is returned, there must be a
huge_zero_page and it can be replaced with returning
'true' when we do not care about the value of huge_zero_page.
We can thus make it return bool to save READ_ONCE cpu cycles as the
return value is just used to check if huge_zero_page exists.
Link: https://lkml.kernel.org/r/20210318122722.13135-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michel Lespinasse <walken@google.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Thomas Hellstrm (Intel) <thomas_os@shipmail.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: yuleixzhang <yulei.kernel@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/huge_memory.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index ae16a82da823..01b96c638e73 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -77,18 +77,18 @@ bool transparent_hugepage_enabled(struct vm_area_struct *vma) return false; } -static struct page *get_huge_zero_page(void) +static bool get_huge_zero_page(void) { struct page *zero_page; retry: if (likely(atomic_inc_not_zero(&huge_zero_refcount))) - return READ_ONCE(huge_zero_page); + return true; zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, HPAGE_PMD_ORDER); if (!zero_page) { count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); - return NULL; + return false; } count_vm_event(THP_ZERO_PAGE_ALLOC); preempt_disable(); @@ -101,7 +101,7 @@ retry: /* We take additional reference here. It will be put back by shrinker */ atomic_set(&huge_zero_refcount, 2); preempt_enable(); - return READ_ONCE(huge_zero_page); + return true; } static void put_huge_zero_page(void) |