[patch] mm, memcg: sync allocation and memcg charge gfp flags for thp fix fix

From: David Rientjes
Date: Thu Apr 02 2015 - 21:41:26 EST


"mm, memcg: sync allocation and memcg charge gfp flags for THP" in -mm
introduces a formal to pass the gfp mask for khugepaged's hugepage
allocation. This is just too ugly to live.

alloc_hugepage_gfpmask() cannot differ between NUMA and UMA configs by
anything in GFP_RECLAIM_MASK, which is the only thing that matters for
memcg reclaim, so just determine the gfp flags once in
collapse_huge_page() and avoid the complexity.

Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
---
-mm: intended to be folded into
mm-memcg-sync-allocation-and-memcg-charge-gfp-flags-for-thp.patch

mm/huge_memory.c | 21 ++++++++-------------
1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2373,16 +2373,12 @@ 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,
+khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long address,
int node)
{
VM_BUG_ON_PAGE(*hpage, *hpage);

- /* Only allocate from the target node */
- *gfp = alloc_hugepage_gfpmask(khugepaged_defrag(), __GFP_OTHER_NODE) |
- __GFP_THISNODE;
-
/*
* Before allocating the hugepage, release the mmap_sem read lock.
* The allocation can take potentially a long time if it involves
@@ -2391,7 +2387,7 @@ khugepaged_alloc_page(struct page **hpage, gfp_t *gfp, struct mm_struct *mm,
*/
up_read(&mm->mmap_sem);

- *hpage = alloc_pages_exact_node(node, *gfp, HPAGE_PMD_ORDER);
+ *hpage = alloc_pages_exact_node(node, gfp, HPAGE_PMD_ORDER);
if (unlikely(!*hpage)) {
count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
*hpage = ERR_PTR(-ENOMEM);
@@ -2445,18 +2441,13 @@ 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,
+khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long address,
int node)
{
up_read(&mm->mmap_sem);
VM_BUG_ON(!*hpage);

- /*
- * khugepaged_alloc_hugepage is doing the preallocation, use the same
- * gfp flags here.
- */
- *gfp = alloc_hugepage_gfpmask(khugepaged_defrag(), 0);
return *hpage;
}
#endif
@@ -2495,8 +2486,12 @@ static void collapse_huge_page(struct mm_struct *mm,

VM_BUG_ON(address & ~HPAGE_PMD_MASK);

+ /* Only allocate from the target node */
+ gfp = alloc_hugepage_gfpmask(khugepaged_defrag(), __GFP_OTHER_NODE) |
+ __GFP_THISNODE;
+
/* release the mmap_sem read lock. */
- new_page = khugepaged_alloc_page(hpage, &gfp, mm, vma, address, node);
+ new_page = khugepaged_alloc_page(hpage, gfp, mm, vma, address, node);
if (!new_page)
return;

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