mm/hugetlb: make hugetlb migration callback CMA aware (bbe88753) · Commits · 戴 / test

new_non_cma_page() in gup.c requires to allocate the new page that is not on the CMA area. new_non_cma_page() implements it by using allocation scope APIs. However, there is a work-around for hugetlb. Normal hugetlb page allocation API for migration is alloc_huge_page_nodemask(). It consists of two steps. First is dequeing from the pool. Second is, if there is no available page on the queue, allocating by using the page allocator. new_non_cma_page() can't use this API since first step (deque) isn't aware of scope API to exclude CMA area. So, new_non_cma_page() exports hugetlb internal function for the second step, alloc_migrate_huge_page(), to global scope and uses it directly. This is suboptimal since hugetlb pages on the queue cannot be utilized. This patch tries to fix this situation by making the deque function on hugetlb CMA aware. In the deque function, CMA memory is skipped if PF_MEMALLOC_NOCMA flag is found. Signed-off-by:

Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Acked-by:

Mike Kravetz <mike.kravetz@oracle.com> Acked-by:

Vlastimil Babka <vbabka@suse.cz> Acked-by:

Michal Hocko <mhocko@suse.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Roman Gushchin <guro@fb.com> Link: http://lkml.kernel.org/r/1596180906-8442-2-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

include/linux/hugetlb.h

+0 −2

Original line number	Diff line number	Diff line
		@@ -511,8 +511,6 @@ struct page alloc_huge_page_nodemask(struct hstate h, int preferred_nid,
		nodemask_t *nmask, gfp_t gfp_mask);
		struct page alloc_huge_page_vma(struct hstate h, struct vm_area_struct *vma,
		unsigned long address);
		struct page alloc_migrate_huge_page(struct hstate h, gfp_t gfp_mask,
		int nid, nodemask_t *nmask);
		int huge_add_to_page_cache(struct page page, struct address_space mapping,
		pgoff_t idx);

mm/gup.c

+1 −5

Original line number	Diff line number	Diff line
		@@ -1635,11 +1635,7 @@ static struct page new_non_cma_page(struct page page, unsigned long private)
		struct hstate *h = page_hstate(page);

		gfp_mask = htlb_modify_alloc_mask(h, gfp_mask);
		/*
		* We don't want to dequeue from the pool because pool pages will
		* mostly be from the CMA region.
		*/
		return alloc_migrate_huge_page(h, gfp_mask, nid, NULL);
		return alloc_huge_page_nodemask(h, nid, NULL, gfp_mask);
		}
		#endif
		if (PageTransHuge(page)) {

mm/hugetlb.c

+9 −2

Original line number	Diff line number	Diff line
		@@ -19,6 +19,7 @@
		#include <linux/memblock.h>
		#include <linux/sysfs.h>
		#include <linux/slab.h>
		#include <linux/sched/mm.h>
		#include <linux/mmdebug.h>
		#include <linux/sched/signal.h>
		#include <linux/rmap.h>
		@@ -1040,10 +1041,16 @@ static void enqueue_huge_page(struct hstate h, struct page page)
		static struct page dequeue_huge_page_node_exact(struct hstate h, int nid)
		{
		struct page *page;
		bool nocma = !!(current->flags & PF_MEMALLOC_NOCMA);

		list_for_each_entry(page, &h->hugepage_freelists[nid], lru) {
		if (nocma && is_migrate_cma_page(page))
		continue;

		list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
		if (!PageHWPoison(page))
		break;
		}

		/*
		* if 'non-isolated free hugepage' not found on the list,
		* the allocation fails.
		@@ -1935,7 +1942,7 @@ out_unlock:
		return page;
		}

		struct page alloc_migrate_huge_page(struct hstate h, gfp_t gfp_mask,
		static struct page alloc_migrate_huge_page(struct hstate h, gfp_t gfp_mask,
		int nid, nodemask_t *nmask)
		{
		struct page *page;

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