[PATCH v7 2/5] mm/memplicy: add page allocation function for MPOL_PREFERRED_MANY policy
From: Feng Tang <hidden>
Date: 2021-08-03 05:59:42
Also in:
linux-api, lkml
Subsystem:
memory management, memory management - memory policy and migration, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
The semantics of MPOL_PREFERRED_MANY is similar to MPOL_PREFERRED, that it will first try to allocate memory from the preferred node(s), and fallback to all nodes in system when first try fails. Add a dedicated function alloc_pages_preferred_many() for it just like for 'interleave' policy, which will be used by 2 general memoory allocation APIs: alloc_pages() and alloc_pages_vma() Link: https://lore.kernel.org/r/20200630212517.308045-9-ben.widawsky@intel.com (local) Suggested-by: Michal Hocko <mhocko@suse.com> Originally-by: Ben Widawsky [off-list ref] Co-developed-by: Ben Widawsky <redacted> Signed-off-by: Ben Widawsky <redacted> Signed-off-by: Feng Tang <redacted> --- mm/mempolicy.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 72f7ff760989..a00bb1c48a15 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c@@ -2166,6 +2166,27 @@ static struct page *alloc_page_interleave(gfp_t gfp, unsigned order, return page; } +static struct page *alloc_pages_preferred_many(gfp_t gfp, unsigned int order, + int nid, struct mempolicy *pol) +{ + struct page *page; + gfp_t preferred_gfp; + + /* + * This is a two pass approach. The first pass will only try the + * preferred nodes but skip the direct reclaim and allow the + * allocation to fail, while the second pass will try all the + * nodes in system. + */ + preferred_gfp = gfp | __GFP_NOWARN; + preferred_gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL); + page = __alloc_pages(preferred_gfp, order, nid, &pol->nodes); + if (!page) + page = __alloc_pages(gfp, order, numa_node_id(), NULL); + + return page; +} + /** * alloc_pages_vma - Allocate a page for a VMA. * @gfp: GFP flags.
@@ -2201,6 +2222,12 @@ struct page *alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma, goto out; } + if (pol->mode == MPOL_PREFERRED_MANY) { + page = alloc_pages_preferred_many(gfp, order, node, pol); + mpol_cond_put(pol); + goto out; + } + if (unlikely(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hugepage)) { int hpage_node = node;
@@ -2278,6 +2305,9 @@ struct page *alloc_pages(gfp_t gfp, unsigned order) */ if (pol->mode == MPOL_INTERLEAVE) page = alloc_page_interleave(gfp, order, interleave_nodes(pol)); + else if (pol->mode == MPOL_PREFERRED_MANY) + page = alloc_pages_preferred_many(gfp, order, + numa_node_id(), pol); else page = __alloc_pages(gfp, order, policy_node(gfp, pol, numa_node_id()),
--
2.14.1