path: root/mm/mempolicy.c
diff options
authorDavid Rientjes <rientjes@google.com>2018-12-07 14:50:16 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-08 10:26:20 -0800
commit356ff8a9a78fb35d6482584d260c3754dcbdf669 (patch)
tree1893db13840f8d37c1562d417b93827f5425170c /mm/mempolicy.c
parentMerge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost (diff)
Revert "mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask"
This reverts commit 89c83fb539f95491be80cdd5158e6f0ce329e317. This should have been done as part of 2f0799a0ffc0 ("mm, thp: restore node-local hugepage allocations"). The movement of the thp allocation policy from alloc_pages_vma() to alloc_hugepage_direct_gfpmask() was intended to only set __GFP_THISNODE for mempolicies that are not MPOL_BIND whereas the revert could set this regardless of mempolicy. While the check for MPOL_BIND between alloc_hugepage_direct_gfpmask() and alloc_pages_vma() was racy, that has since been removed since the revert. What is left is the possibility to use __GFP_THISNODE in policy_node() when it is unexpected because the special handling for hugepages in alloc_pages_vma() was removed as part of the consolidation. Secondly, prior to 89c83fb539f9, alloc_pages_vma() implemented a somewhat different policy for hugepage allocations, which were allocated through alloc_hugepage_vma(). For hugepage allocations, if the allocating process's node is in the set of allowed nodes, allocate with __GFP_THISNODE for that node (for MPOL_PREFERRED, use that node with __GFP_THISNODE instead). This was changed for shmem_alloc_hugepage() to allow fallback to other nodes in 89c83fb539f9 as it did for new_page() in mm/mempolicy.c which is functionally different behavior and removes the requirement to only allocate hugepages locally. So this commit does a full revert of 89c83fb539f9 instead of the partial revert that was done in 2f0799a0ffc0. The result is the same thp allocation policy for 4.20 that was in 4.19. Fixes: 89c83fb539f9 ("mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask") Fixes: 2f0799a0ffc0 ("mm, thp: restore node-local hugepage allocations") Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
1 files changed, 29 insertions, 3 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 69e278b469ef..d4496d9d34f5 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1116,8 +1116,8 @@ static struct page *new_page(struct page *page, unsigned long start)
} else if (PageTransHuge(page)) {
struct page *thp;
- thp = alloc_pages_vma(GFP_TRANSHUGE, HPAGE_PMD_ORDER, vma,
- address, numa_node_id());
+ thp = alloc_hugepage_vma(GFP_TRANSHUGE, vma, address,
if (!thp)
return NULL;
@@ -2011,6 +2011,7 @@ static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
* @vma: Pointer to VMA or NULL if not available.
* @addr: Virtual Address of the allocation. Must be inside the VMA.
* @node: Which node to prefer for allocation (modulo policy).
+ * @hugepage: for hugepages try only the preferred node if possible
* This function allocates a page from the kernel page pool and applies
* a NUMA policy associated with the VMA or the current process.
@@ -2021,7 +2022,7 @@ static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
struct page *
alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
- unsigned long addr, int node)
+ unsigned long addr, int node, bool hugepage)
struct mempolicy *pol;
struct page *page;
@@ -2039,6 +2040,31 @@ alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
goto out;
+ if (unlikely(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hugepage)) {
+ int hpage_node = node;
+ /*
+ * For hugepage allocation and non-interleave policy which
+ * allows the current node (or other explicitly preferred
+ * node) we only try to allocate from the current/preferred
+ * node and don't fall back to other nodes, as the cost of
+ * remote accesses would likely offset THP benefits.
+ *
+ * If the policy is interleave, or does not allow the current
+ * node in its nodemask, we allocate the standard way.
+ */
+ if (pol->mode == MPOL_PREFERRED && !(pol->flags & MPOL_F_LOCAL))
+ hpage_node = pol->v.preferred_node;
+ nmask = policy_nodemask(gfp, pol);
+ if (!nmask || node_isset(hpage_node, *nmask)) {
+ mpol_cond_put(pol);
+ page = __alloc_pages_node(hpage_node,
+ gfp | __GFP_THISNODE, order);
+ goto out;
+ }
+ }
nmask = policy_nodemask(gfp, pol);
preferred_nid = policy_node(gfp, pol, node);
page = __alloc_pages_nodemask(gfp, order, preferred_nid, nmask);