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khugepaged: move up_read(mmap_sem) out of khugepaged_alloc_page() 

Both variants of khugepaged_alloc_page() do up_read(&mm->mmap_sem)
first: no point keep it inside the function.

Link: http://lkml.kernel.org/r/1466021202-61880-33-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Kirill A. Shutemov 2016-07-26 15:26:26 -07:00 committed by Linus Torvalds
parent b46e756f5e
commit 988ddb710b
1 changed files with 10 additions and 15 deletions
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25
mm/khugepaged.c
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@ -739,19 +739,10 @@ static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
}
static struct page *
khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm,
unsigned long address, int node)
khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node)
{
VM_BUG_ON_PAGE(*hpage, *hpage);
/*
* Before allocating the hugepage, release the mmap_sem read lock.
* The allocation can take potentially a long time if it involves
* sync compaction, and we do not need to hold the mmap_sem during
* that. We will recheck the vma after taking it again in write mode.
*/
up_read(&mm->mmap_sem);
*hpage = __alloc_pages_node(node, gfp, HPAGE_PMD_ORDER);
if (unlikely(!*hpage)) {
count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
@ -812,10 +803,8 @@ static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
}
static struct page *
khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm,
unsigned long address, int node)
khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node)
{
up_read(&mm->mmap_sem);
VM_BUG_ON(!*hpage);
return *hpage;
@ -936,8 +925,14 @@ static void collapse_huge_page(struct mm_struct *mm,
/* Only allocate from the target node */
gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_OTHER_NODE | __GFP_THISNODE;
/* release the mmap_sem read lock. */
new_page = khugepaged_alloc_page(hpage, gfp, mm, address, node);
/*
* Before allocating the hugepage, release the mmap_sem read lock.
* The allocation can take potentially a long time if it involves
* sync compaction, and we do not need to hold the mmap_sem during
* that. We will recheck the vma after taking it again in write mode.
*/
up_read(&mm->mmap_sem);
new_page = khugepaged_alloc_page(hpage, gfp, node);
if (!new_page) {
result = SCAN_ALLOC_HUGE_PAGE_FAIL;
goto out_nolock;