Commit 5265047a authored Apr 14, 2015 by David Rientjes Committed by Linus Torvalds Apr 14, 2015

mm, thp: really limit transparent hugepage allocation to local node



Commit 077fcf11 ("mm/thp: allocate transparent hugepages on local
node") restructured alloc_hugepage_vma() with the intent of only
allocating transparent hugepages locally when there was not an effective
interleave mempolicy.

alloc_pages_exact_node() does not limit the allocation to the single node,
however, but rather prefers it.  This is because __GFP_THISNODE is not set
which would cause the node-local nodemask to be passed.  Without it, only
a nodemask that prefers the local node is passed.

Fix this by passing __GFP_THISNODE and falling back to small pages when
the allocation fails.

Commit 9f1b868a ("mm: thp: khugepaged: add policy for finding target
node") suffers from a similar problem for khugepaged, which is also fixed.

Fixes: 077fcf11 ("mm/thp: allocate transparent hugepages on local node")
Fixes: 9f1b868a ("mm: thp: khugepaged: add policy for finding target node")
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pravin Shelar <pshelar@nicira.com>
Cc: Jarno Rajahalme <jrajahalme@nicira.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 4167e9b2

mm/huge_memory.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -2328,8 +2328,14 @@ static struct page
		struct vm_area_struct *vma, unsigned long address,
		int node)
		{
		gfp_t flags;

		VM_BUG_ON_PAGE(hpage, hpage);

		/* Only allocate from the target node */
		flags = 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
		@@ -2338,8 +2344,7 @@ static struct page
		*/
		up_read(&mm->mmap_sem);

		*hpage = alloc_pages_exact_node(node, alloc_hugepage_gfpmask(
		khugepaged_defrag(), __GFP_OTHER_NODE), HPAGE_PMD_ORDER);
		*hpage = alloc_pages_exact_node(node, flags, HPAGE_PMD_ORDER);
		if (unlikely(!*hpage)) {
		count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
		*hpage = ERR_PTR(-ENOMEM);

mm/mempolicy.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1986,7 +1986,8 @@ alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
		nmask = policy_nodemask(gfp, pol);
		if (!nmask \|\| node_isset(node, *nmask)) {
		mpol_cond_put(pol);
		page = alloc_pages_exact_node(node, gfp, order);
		page = alloc_pages_exact_node(node,
		gfp \| __GFP_THISNODE, order);
		goto out;
		}
		}