From: Zi Yan <zi.yan@sent•com>
To: David Hildenbrand <david@redhat•com>, linux-mm@kvack•org
Cc: Mel Gorman <mgorman@techsingularity•net>, Zi Yan <ziy@nvidia•com>,
Robin Murphy <robin.murphy@arm•com>,
linux-kernel@vger•kernel.org, iommu@lists•linux-foundation.org,
Eric Ren <renzhengeek@gmail•com>,
virtualization@lists•linux-foundation.org,
linuxppc-dev@lists•ozlabs.org, Christoph Hellwig <hch@lst•de>,
Vlastimil Babka <vbabka@suse•cz>,
Marek Szyprowski <m.szyprowski@samsung•com>
Subject: [PATCH v4 1/7] mm: page_alloc: avoid merging non-fallbackable pageblocks with others.
Date: Wed, 19 Jan 2022 14:06:17 -0500 [thread overview]
Message-ID: <20220119190623.1029355-2-zi.yan@sent.com> (raw)
In-Reply-To: <20220119190623.1029355-1-zi.yan@sent.com>
From: Zi Yan <ziy@nvidia•com>
This is done in addition to MIGRATE_ISOLATE pageblock merge avoidance.
It prepares for the upcoming removal of the MAX_ORDER-1 alignment
requirement for CMA and alloc_contig_range().
MIGRARTE_HIGHATOMIC should not merge with other migratetypes like
MIGRATE_ISOLATE and MIGRARTE_CMA[1], so this commit prevents that too.
Also add MIGRARTE_HIGHATOMIC to fallbacks array for completeness.
[1] https://lore.kernel.org/linux-mm/20211130100853.GP3366@techsingularity.net/
Signed-off-by: Zi Yan <ziy@nvidia•com>
---
include/linux/mmzone.h | 11 +++++++++++
mm/page_alloc.c | 37 ++++++++++++++++++++-----------------
2 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index aed44e9b5d89..71b77aab748d 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -83,6 +83,17 @@ static inline bool is_migrate_movable(int mt)
return is_migrate_cma(mt) || mt == MIGRATE_MOVABLE;
}
+/*
+ * Check whether a migratetype can be merged with another migratetype.
+ *
+ * It is only mergeable when it can fall back to other migratetypes for
+ * allocation. See fallbacks[MIGRATE_TYPES][3] in page_alloc.c.
+ */
+static inline bool migratetype_is_mergeable(int mt)
+{
+ return mt < MIGRATE_PCPTYPES;
+}
+
#define for_each_migratetype_order(order, type) \
for (order = 0; order < MAX_ORDER; order++) \
for (type = 0; type < MIGRATE_TYPES; type++)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8dd6399bafb5..15de65215c02 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1117,25 +1117,24 @@ static inline void __free_one_page(struct page *page,
}
if (order < MAX_ORDER - 1) {
/* If we are here, it means order is >= pageblock_order.
- * We want to prevent merge between freepages on isolate
- * pageblock and normal pageblock. Without this, pageblock
- * isolation could cause incorrect freepage or CMA accounting.
+ * We want to prevent merge between freepages on pageblock
+ * without fallbacks and normal pageblock. Without this,
+ * pageblock isolation could cause incorrect freepage or CMA
+ * accounting or HIGHATOMIC accounting.
*
* We don't want to hit this code for the more frequent
* low-order merging.
*/
- if (unlikely(has_isolate_pageblock(zone))) {
- int buddy_mt;
+ int buddy_mt;
- buddy_pfn = __find_buddy_pfn(pfn, order);
- buddy = page + (buddy_pfn - pfn);
- buddy_mt = get_pageblock_migratetype(buddy);
+ buddy_pfn = __find_buddy_pfn(pfn, order);
+ buddy = page + (buddy_pfn - pfn);
+ buddy_mt = get_pageblock_migratetype(buddy);
- if (migratetype != buddy_mt
- && (is_migrate_isolate(migratetype) ||
- is_migrate_isolate(buddy_mt)))
- goto done_merging;
- }
+ if (migratetype != buddy_mt
+ && (!migratetype_is_mergeable(migratetype) ||
+ !migratetype_is_mergeable(buddy_mt)))
+ goto done_merging;
max_order = order + 1;
goto continue_merging;
}
@@ -2484,6 +2483,7 @@ static int fallbacks[MIGRATE_TYPES][3] = {
[MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_TYPES },
[MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES },
[MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_TYPES },
+ [MIGRATE_HIGHATOMIC] = { MIGRATE_TYPES }, /* Never used */
#ifdef CONFIG_CMA
[MIGRATE_CMA] = { MIGRATE_TYPES }, /* Never used */
#endif
@@ -2795,8 +2795,8 @@ static void reserve_highatomic_pageblock(struct page *page, struct zone *zone,
/* Yoink! */
mt = get_pageblock_migratetype(page);
- if (!is_migrate_highatomic(mt) && !is_migrate_isolate(mt)
- && !is_migrate_cma(mt)) {
+ /* Only reserve normal pageblocks (i.e., they can merge with others) */
+ if (migratetype_is_mergeable(mt)) {
zone->nr_reserved_highatomic += pageblock_nr_pages;
set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC);
move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL);
@@ -3545,8 +3545,11 @@ int __isolate_free_page(struct page *page, unsigned int order)
struct page *endpage = page + (1 << order) - 1;
for (; page < endpage; page += pageblock_nr_pages) {
int mt = get_pageblock_migratetype(page);
- if (!is_migrate_isolate(mt) && !is_migrate_cma(mt)
- && !is_migrate_highatomic(mt))
+ /*
+ * Only change normal pageblocks (i.e., they can merge
+ * with others)
+ */
+ if (migratetype_is_mergeable(mt))
set_pageblock_migratetype(page,
MIGRATE_MOVABLE);
}
--
2.34.1
next prev parent reply other threads:[~2022-01-19 19:10 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-19 19:06 [PATCH v4 0/7] Use pageblock_order for cma and alloc_contig_range alignment Zi Yan
2022-01-19 19:06 ` Zi Yan [this message]
2022-01-24 14:02 ` [PATCH v4 1/7] mm: page_alloc: avoid merging non-fallbackable pageblocks with others Mel Gorman
2022-01-24 16:12 ` Zi Yan
2022-01-24 16:43 ` Mel Gorman
2022-01-19 19:06 ` [PATCH v4 2/7] mm: page_isolation: move has_unmovable_pages() to mm/page_isolation.c Zi Yan
2022-01-25 6:23 ` Oscar Salvador
2022-01-19 19:06 ` [PATCH v4 3/7] mm: page_isolation: check specified range for unmovable pages Zi Yan
2022-01-24 9:55 ` Oscar Salvador
2022-01-24 17:17 ` Zi Yan
2022-01-25 13:19 ` Oscar Salvador
2022-01-25 13:21 ` Oscar Salvador
2022-01-25 16:31 ` Zi Yan
2022-02-02 12:18 ` Oscar Salvador
2022-02-02 12:25 ` David Hildenbrand
2022-02-02 16:25 ` Zi Yan
2022-02-02 16:35 ` Oscar Salvador
2022-01-19 19:06 ` [PATCH v4 4/7] mm: make alloc_contig_range work at pageblock granularity Zi Yan
2022-02-04 13:56 ` Oscar Salvador
2022-02-04 15:19 ` Zi Yan
2022-01-19 19:06 ` [PATCH v4 5/7] mm: cma: use pageblock_order as the single alignment Zi Yan
2022-01-19 19:06 ` [PATCH v4 6/7] drivers: virtio_mem: use pageblock size as the minimum virtio_mem size Zi Yan
2022-01-19 19:06 ` [PATCH v4 7/7] arch: powerpc: adjust fadump alignment to be pageblock aligned Zi Yan
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