Commit d1e153fe authored by Pavel Tatashin's avatar Pavel Tatashin Committed by Linus Torvalds
Browse files

mm/gup: migrate pinned pages out of movable zone 

We should not pin pages in ZONE_MOVABLE.  Currently, we do not pin only
movable CMA pages.  Generalize the function that migrates CMA pages to
migrate all movable pages.  Use is_pinnable_page() to check which pages
need to be migrated

Link: https://lkml.kernel.org/r/20210215161349.246722-10-pasha.tatashin@soleen.com


Signed-off-by: default avatarPavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Tyler Hicks <tyhicks@linux.microsoft.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9afaf30f

include/linux/migrate.h

+1 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ enum migrate_reason { 
	MR_MEMPOLICY_MBIND,

	MR_NUMA_MISPLACED,

	MR_CONTIG_RANGE,

	MR_LONGTERM_PIN,

	MR_TYPES

};

include/linux/mmzone.h

+7 −2
Original line number Diff line number Diff line
@@ -407,8 +407,13 @@ enum zone_type { 
	 * to increase the number of THP/huge pages. Notable special cases are:

	 *

	 * 1. Pinned pages: (long-term) pinning of movable pages might

	 *    essentially turn such pages unmovable. Memory offlining might

	 *    retry a long time.

	 *    essentially turn such pages unmovable. Therefore, we do not allow

	 *    pinning long-term pages in ZONE_MOVABLE. When pages are pinned and

	 *    faulted, they come from the right zone right away. However, it is

	 *    still possible that address space already has pages in

	 *    ZONE_MOVABLE at the time when pages are pinned (i.e. user has

	 *    touches that memory before pinning). In such case we migrate them

	 *    to a different zone. When migration fails - pinning fails.

	 * 2. memblock allocations: kernelcore/movablecore setups might create

	 *    situations where ZONE_MOVABLE contains unmovable allocations

	 *    after boot. Memory offlining and allocations fail early.

include/trace/events/migrate.h

+2 −1
Original line number Diff line number Diff line
@@ -20,7 +20,8 @@ 
	EM( MR_SYSCALL,		"syscall_or_cpuset")		\

	EM( MR_MEMPOLICY_MBIND,	"mempolicy_mbind")		\

	EM( MR_NUMA_MISPLACED,	"numa_misplaced")		\

	EMe(MR_CONTIG_RANGE,	"contig_range")

	EM( MR_CONTIG_RANGE,	"contig_range")			\

	EMe(MR_LONGTERM_PIN,	"longterm_pin")



/*

 * First define the enums in the above macros to be exported to userspace

mm/gup.c

+34 −33
Original line number Diff line number Diff line
@@ -87,11 +87,12 @@ __maybe_unused struct page *try_grab_compound_head(struct page *page, 
		int orig_refs = refs;



		/*

		 * Can't do FOLL_LONGTERM + FOLL_PIN with CMA in the gup fast

		 * path, so fail and let the caller fall back to the slow path.

		 * Can't do FOLL_LONGTERM + FOLL_PIN gup fast path if not in a

		 * right zone, so fail and let the caller fall back to the slow

		 * path.

		 */

		if (unlikely(flags & FOLL_LONGTERM) &&

				is_migrate_cma_page(page))

		if (unlikely((flags & FOLL_LONGTERM) &&

			     !is_pinnable_page(page)))

			return NULL;



		/*
@@ -1600,8 +1601,8 @@ struct page *get_dump_page(unsigned long addr) 
}

#endif /* CONFIG_ELF_CORE */



#ifdef CONFIG_CMA

static long check_and_migrate_cma_pages(struct mm_struct *mm,

#ifdef CONFIG_MIGRATION

static long check_and_migrate_movable_pages(struct mm_struct *mm,

					    unsigned long start,

					    unsigned long nr_pages,

					    struct page **pages,
@@ -1610,7 +1611,7 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm, 
{

	unsigned long i, isolation_error_count;

	bool drain_allow;

	LIST_HEAD(cma_page_list);

	LIST_HEAD(movable_page_list);

	long ret = nr_pages;

	struct page *prev_head, *head;

	struct migration_target_control mtc = {
@@ -1628,13 +1629,12 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm, 
			continue;

		prev_head = head;

		/*

		 * If we get a page from the CMA zone, since we are going to

		 * be pinning these entries, we might as well move them out

		 * of the CMA zone if possible.

		 * If we get a movable page, since we are going to be pinning

		 * these entries, try to move them out if possible.

		 */

		if (is_migrate_cma_page(head)) {

		if (!is_pinnable_page(head)) {

			if (PageHuge(head)) {

				if (!isolate_huge_page(head, &cma_page_list))

				if (!isolate_huge_page(head, &movable_page_list))

					isolation_error_count++;

			} else {

				if (!PageLRU(head) && drain_allow) {
@@ -1646,7 +1646,7 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm, 
					isolation_error_count++;

					continue;

				}

				list_add_tail(&head->lru, &cma_page_list);

				list_add_tail(&head->lru, &movable_page_list);

				mod_node_page_state(page_pgdat(head),

						    NR_ISOLATED_ANON +

						    page_is_file_lru(head),
@@ -1659,10 +1659,10 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm, 
	 * If list is empty, and no isolation errors, means that all pages are

	 * in the correct zone.

	 */

	if (list_empty(&cma_page_list) && !isolation_error_count)

	if (list_empty(&movable_page_list) && !isolation_error_count)

		return ret;



	if (!list_empty(&cma_page_list)) {

	if (!list_empty(&movable_page_list)) {

		/*

		 * drop the above get_user_pages reference.

		 */
@@ -1672,12 +1672,12 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm, 
			for (i = 0; i < nr_pages; i++)

				put_page(pages[i]);



		ret = migrate_pages(&cma_page_list, alloc_migration_target,

		ret = migrate_pages(&movable_page_list, alloc_migration_target,

				    NULL, (unsigned long)&mtc, MIGRATE_SYNC,

				    MR_CONTIG_RANGE);

				    MR_LONGTERM_PIN);

		if (ret) {

			if (!list_empty(&cma_page_list))

				putback_movable_pages(&cma_page_list);

			if (!list_empty(&movable_page_list))

				putback_movable_pages(&movable_page_list);

			return ret > 0 ? -ENOMEM : ret;

		}
@@ -1696,7 +1696,7 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm, 
	goto check_again;

}

#else

static long check_and_migrate_cma_pages(struct mm_struct *mm,

static long check_and_migrate_movable_pages(struct mm_struct *mm,

					    unsigned long start,

					    unsigned long nr_pages,

					    struct page **pages,
@@ -1705,7 +1705,7 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm, 
{

	return nr_pages;

}

#endif /* CONFIG_CMA */

#endif /* CONFIG_MIGRATION */



/*

 * __gup_longterm_locked() is a wrapper for __get_user_pages_locked which
@@ -1729,8 +1729,9 @@ static long __gup_longterm_locked(struct mm_struct *mm, 


	if (gup_flags & FOLL_LONGTERM) {

		if (rc > 0)

			rc = check_and_migrate_cma_pages(mm, start, rc, pages,

							 vmas, gup_flags);

			rc = check_and_migrate_movable_pages(mm, start, rc,

							     pages, vmas,

							     gup_flags);

		memalloc_pin_restore(flags);

	}

	return rc;