* [merged] mm-huge_memoryc-make-get_huge_zero_page-return-bool.patch removed from -mm tree
@ 2021-05-08 22:46 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2021-05-08 22:46 UTC (permalink / raw)
To: aneesh.kumar, linmiaohe, mm-commits, peterx, rcampbell,
richard.weiyang, thomas_os, vbabka, walken, william.kucharski,
willy, yang.shi, yulei.kernel, ziy
The patch titled
Subject: mm/huge_memory.c: make get_huge_zero_page() return bool
has been removed from the -mm tree. Its filename was
mm-huge_memoryc-make-get_huge_zero_page-return-bool.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Miaohe Lin <linmiaohe@huawei.com>
Subject: 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>
---
mm/huge_memory.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/mm/huge_memory.c~mm-huge_memoryc-make-get_huge_zero_page-return-bool
+++ a/mm/huge_memory.c
@@ -77,18 +77,18 @@ bool transparent_hugepage_enabled(struct
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)
_
Patches currently in -mm which might be from linmiaohe@huawei.com are
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2021-05-08 22:46 [merged] mm-huge_memoryc-make-get_huge_zero_page-return-bool.patch removed from -mm tree akpm
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