linux-kernel - [PATCH 4.0 211/220] mm, thp: really limit transparent hugepage allocation to local node

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Message-Id: <20150502185903.378934945@linuxfoundation.org>
Date:	Sat,  2 May 2015 21:02:06 +0200
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, David Rientjes <rientjes@...gle.com>,
	Vlastimil Babka <vbabka@...e.cz>,
	Christoph Lameter <cl@...ux.com>,
	Pekka Enberg <penberg@...nel.org>,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	Johannes Weiner <hannes@...xchg.org>,
	Mel Gorman <mgorman@...e.de>,
	Pravin Shelar <pshelar@...ira.com>,
	Jarno Rajahalme <jrajahalme@...ira.com>,
	Li Zefan <lizefan@...wei.com>,
	Greg Thelen <gthelen@...gle.com>, Tejun Heo <tj@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH 4.0 211/220] mm, thp: really limit transparent hugepage allocation to local node

4.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Rientjes <rientjes@...gle.com>

commit 5265047ac30191ea24b16503165000c225f54feb upstream.

Commit 077fcf116c8c ("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 9f1b868a13ac ("mm: thp: khugepaged: add policy for finding target
node") suffers from a similar problem for khugepaged, which is also fixed.

Fixes: 077fcf116c8c ("mm/thp: allocate transparent hugepages on local node")
Fixes: 9f1b868a13ac ("mm: thp: khugepaged: add policy for finding target node")
Signed-off-by: David Rientjes <rientjes@...gle.com>
Acked-by: Vlastimil Babka <vbabka@...e.cz>
Cc: Christoph Lameter <cl@...ux.com>
Cc: Pekka Enberg <penberg@...nel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@....com>
Cc: Johannes Weiner <hannes@...xchg.org>
Cc: Mel Gorman <mgorman@...e.de>
Cc: Pravin Shelar <pshelar@...ira.com>
Cc: Jarno Rajahalme <jrajahalme@...ira.com>
Cc: Li Zefan <lizefan@...wei.com>
Cc: Greg Thelen <gthelen@...gle.com>
Cc: Tejun Heo <tj@...nel.org>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 mm/huge_memory.c |    9 +++++++--
 mm/mempolicy.c   |    3 ++-
 2 files changed, 9 insertions(+), 3 deletions(-)

--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2316,8 +2316,14 @@ 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
@@ -2326,8 +2332,7 @@ 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);
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1985,7 +1985,8 @@ retry_cpuset:
 		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;
 		}
 	}


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