* [PATCH v7 0/4] Enable >0 order folio memory compaction
@ 2024-02-20 18:32 Zi Yan
2024-02-20 18:32 ` [PATCH v7 1/4] mm/page_alloc: remove unused fpi_flags in free_pages_prepare() Zi Yan
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: Zi Yan @ 2024-02-20 18:32 UTC (permalink / raw)
To: linux-mm, linux-kernel
Cc: Zi Yan, Huang, Ying, Ryan Roberts, Andrew Morton,
Matthew Wilcox (Oracle),
David Hildenbrand, Yin, Fengwei, Yu Zhao, Vlastimil Babka,
Kirill A . Shutemov, Johannes Weiner, Baolin Wang, Kemeng Shi,
Mel Gorman, Rohan Puri, Mcgrof Chamberlain, Adam Manzanares,
Vishal Moola (Oracle)
From: Zi Yan <ziy@nvidia.com>
Hi all,
This patchset enables >0 order folio memory compaction, which is one of
the prerequisitions for large folio support[1]. It is on top of
mm-everything-2024-02-20-04-19 (with V6 removed).
I am aware of that split free pages is necessary for folio
migration in compaction, since if >0 order free pages are never split
and no order-0 free page is scanned, compaction will end prematurely due
to migration returns -ENOMEM. Free page split becomes a must instead of
an optimization.
lkp ncompare results (on a 8-CPU (Intel Xeon E5-2650 v4 @2.20GHz) 16G VM)
for default LRU (-no-mglru) and CONFIG_LRU_GEN are shown at the bottom,
copied from V3[4].
In sum, most of vm-scalability applications do not see performance
change, and the others see ~4% to ~26% performance boost under default LRU
and ~2% to ~6% performance boost under CONFIG_LRU_GEN.
Changelog
===
From V6 [7]:
1. Properly commented skip_isolation_on_order() (per David Hildenbrand).
2. Fixed folio_test_large() check (per David Hildenbrand).
3. Used is_via_compact_memory() instead of order == -1 check (per David
Hildenbrand).
From V5 [6]:
1. Removed unused parameter in prepare_free_pages() and used it instead
of my old prepare_free_pages_fpi_none() (per Vlastimil Babka).
2. Removed unnecessary INIT_LIST_HEAD() in compaction_free()
(per Vlastimil Babka).
3. Fixed cc->nr_migratepages update in compaction_free()
(per Vlastimil Babka).
From V4 [5]:
1. Refactored code in compaction_alloc() in Patch 3 (per Yu Zhao).
From V3 [4]:
1. Restructured isolate_migratepages_block() to minimize PageHuge() use
in Patch 1 (per Vlastimil Babka).
2. Used folio_put_testzero() instead of folio_set_count() to properly
handle free pages in compaction_free() (per Vlastimil Babka).
3. Simplified code to use struct list_head instead of a new struct page_list
(per Vlastimil Babka).
4. Restructured compaction_alloc() code to reduce indentation and
increase readability (per Vlastimil Babka).
From V2 [3]:
1. Added missing free page count in fast isolation path. This fixed the
weird performance outcome.
From V1 [2]:
1. Used folio_test_large() instead of folio_order() > 0. (per Matthew
Wilcox)
2. Fixed code rebase error. (per Baolin Wang)
3. Used list_split_init() instead of list_split(). (per Ryan Boberts)
4. Added free_pages_prepare_fpi_none() to avoid duplicate free page code
in compaction_free().
5. Dropped source page order sorting patch.
From RFC [1]:
1. Enabled >0 order folio compaction in the first patch by splitting all
to-be-migrated folios. (per Huang, Ying)
2. Stopped isolating compound pages with order greater than cc->order
to avoid wasting effort, since cc->order gives a hint that no free pages
with order greater than it exist, thus migrating the compound pages will fail.
(per Baolin Wang)
3. Retained the folio check within lru lock. (per Baolin Wang)
4. Made isolate_freepages_block() generate order-sorted multi lists.
(per Johannes Weiner)
Overview
===
To support >0 order folio compaction, the patchset changes how free pages used
for migration are kept during compaction. Free pages used to be split into
order-0 pages that are post allocation processed (i.e., PageBuddy flag cleared,
page order stored in page->private is zeroed, and page reference is set to 1).
Now all free pages are kept in a NR_PAGE_ORDER array of page lists based
on their order without post allocation process. When migrate_pages() asks for
a new page, one of the free pages, based on the requested page order, is
then processed and given out. And THP <2MB would need this feature.
Feel free to give comments and ask questions.
Thanks.
[1] https://lore.kernel.org/linux-mm/f8d47176-03a8-99bf-a813-b5942830fd73@arm.com/
[2] https://lore.kernel.org/linux-mm/20231113170157.280181-1-zi.yan@sent.com/
[3] https://lore.kernel.org/linux-mm/20240123034636.1095672-1-zi.yan@sent.com/
[4] https://lore.kernel.org/linux-mm/20240202161554.565023-1-zi.yan@sent.com/
[5] https://lore.kernel.org/linux-mm/20240212163510.859822-1-zi.yan@sent.com/
[6] https://lore.kernel.org/linux-mm/20240214220420.1229173-1-zi.yan@sent.com/
[7] https://lore.kernel.org/linux-mm/20240216170432.1268753-1-zi.yan@sent.com/
vm-scalability results on CONFIG_LRU_GEN
===
=========================================================================================
compiler/kconfig/rootfs/runtime/tbox_group/test/testcase:
gcc-13/defconfig/debian/300s/qemu-vm/mmap-xread-seq-mt/vm-scalability
commit:
6.8.0-rc1-mm-everything-2024-01-29-07-19+
6.8.0-rc1-split-folio-in-compaction+
6.8.0-rc1-folio-migration-in-compaction+
6.8.0-rc1-folio-migration-free-page-split+
6.8.0-rc1-mm-eve 6.8.0-rc1-split-folio-in-co 6.8.0-rc1-folio-migration-i 6.8.0-rc1-folio-migration-f
---------------- --------------------------- --------------------------- ---------------------------
%stddev %change %stddev %change %stddev %change %stddev
\ | \ | \ | \
15107616 +3.2% 15590339 +1.3% 15297619 +3.0% 15567998 vm-scalability.throughput
=========================================================================================
compiler/kconfig/rootfs/runtime/tbox_group/test/testcase:
gcc-13/defconfig/debian/300s/qemu-vm/mmap-pread-seq/vm-scalability
commit:
6.8.0-rc1-mm-everything-2024-01-29-07-19+
6.8.0-rc1-split-folio-in-compaction+
6.8.0-rc1-folio-migration-in-compaction+
6.8.0-rc1-folio-migration-free-page-split+
6.8.0-rc1-mm-eve 6.8.0-rc1-split-folio-in-co 6.8.0-rc1-folio-migration-i 6.8.0-rc1-folio-migration-f
---------------- --------------------------- --------------------------- ---------------------------
%stddev %change %stddev %change %stddev %change %stddev
\ | \ | \ | \
12611785 +1.8% 12832919 +0.9% 12724223 +1.6% 12812682 vm-scalability.throughput
=========================================================================================
compiler/kconfig/rootfs/runtime/tbox_group/test/testcase:
gcc-13/defconfig/debian/300s/qemu-vm/lru-file-readtwice/vm-scalability
commit:
6.8.0-rc1-mm-everything-2024-01-29-07-19+
6.8.0-rc1-split-folio-in-compaction+
6.8.0-rc1-folio-migration-in-compaction+
6.8.0-rc1-folio-migration-free-page-split+
6.8.0-rc1-mm-eve 6.8.0-rc1-split-folio-in-co 6.8.0-rc1-folio-migration-i 6.8.0-rc1-folio-migration-f
---------------- --------------------------- --------------------------- ---------------------------
%stddev %change %stddev %change %stddev %change %stddev
\ | \ | \ | \
9833393 +5.7% 10390190 +3.0% 10126606 +5.9% 10408804 vm-scalability.throughput
=========================================================================================
compiler/kconfig/rootfs/runtime/tbox_group/test/testcase:
gcc-13/defconfig/debian/300s/qemu-vm/lru-file-mmap-read/vm-scalability
commit:
6.8.0-rc1-mm-everything-2024-01-29-07-19+
6.8.0-rc1-split-folio-in-compaction+
6.8.0-rc1-folio-migration-in-compaction+
6.8.0-rc1-folio-migration-free-page-split+
6.8.0-rc1-mm-eve 6.8.0-rc1-split-folio-in-co 6.8.0-rc1-folio-migration-i 6.8.0-rc1-folio-migration-f
---------------- --------------------------- --------------------------- ---------------------------
%stddev %change %stddev %change %stddev %change %stddev
\ | \ | \ | \
7034709 ± 3% +2.9% 7241429 +3.2% 7256680 ± 2% +3.9% 7308375 vm-scalability.throughput
vm-scalability results on default LRU (with -no-mglru suffix)
===
=========================================================================================
compiler/kconfig/rootfs/runtime/tbox_group/test/testcase:
gcc-13/defconfig/debian/300s/qemu-vm/mmap-xread-seq-mt/vm-scalability
commit:
6.8.0-rc1-mm-everything-2024-01-29-07-19-no-mglru+
6.8.0-rc1-split-folio-in-compaction-no-mglru+
6.8.0-rc1-folio-migration-in-compaction-no-mglru+
6.8.0-rc1-folio-migration-free-page-split-no-mglru+
6.8.0-rc1-mm-eve 6.8.0-rc1-split-folio-in-co 6.8.0-rc1-folio-migration-i 6.8.0-rc1-folio-migration-f
---------------- --------------------------- --------------------------- ---------------------------
%stddev %change %stddev %change %stddev %change %stddev
\ | \ | \ | \
14401491 +3.7% 14940270 +2.4% 14748626 +4.0% 14975716 vm-scalability.throughput
=========================================================================================
compiler/kconfig/rootfs/runtime/tbox_group/test/testcase:
gcc-13/defconfig/debian/300s/qemu-vm/mmap-pread-seq/vm-scalability
commit:
6.8.0-rc1-mm-everything-2024-01-29-07-19-no-mglru+
6.8.0-rc1-split-folio-in-compaction-no-mglru+
6.8.0-rc1-folio-migration-in-compaction-no-mglru+
6.8.0-rc1-folio-migration-free-page-split-no-mglru+
6.8.0-rc1-mm-eve 6.8.0-rc1-split-folio-in-co 6.8.0-rc1-folio-migration-i 6.8.0-rc1-folio-migration-f
---------------- --------------------------- --------------------------- ---------------------------
%stddev %change %stddev %change %stddev %change %stddev
\ | \ | \ | \
11407497 +5.1% 11989632 -0.5% 11349272 +4.8% 11957423 vm-scalability.throughput
=========================================================================================
compiler/kconfig/rootfs/runtime/tbox_group/test/testcase:
gcc-13/defconfig/debian/300s/qemu-vm/mmap-pread-seq-mt/vm-scalability
commit:
6.8.0-rc1-mm-everything-2024-01-29-07-19-no-mglru+
6.8.0-rc1-split-folio-in-compaction-no-mglru+
6.8.0-rc1-folio-migration-in-compaction-no-mglru+
6.8.0-rc1-folio-migration-free-page-split-no-mglru+
6.8.0-rc1-mm-eve 6.8.0-rc1-split-folio-in-co 6.8.0-rc1-folio-migration-i 6.8.0-rc1-folio-migration-f
---------------- --------------------------- --------------------------- ---------------------------
%stddev %change %stddev %change %stddev %change %stddev
\ | \ | \ | \
11348474 +3.3% 11719453 -1.2% 11208759 +3.7% 11771926 vm-scalability.throughput
=========================================================================================
compiler/kconfig/rootfs/runtime/tbox_group/test/testcase:
gcc-13/defconfig/debian/300s/qemu-vm/lru-file-readtwice/vm-scalability
commit:
6.8.0-rc1-mm-everything-2024-01-29-07-19-no-mglru+
6.8.0-rc1-split-folio-in-compaction-no-mglru+
6.8.0-rc1-folio-migration-in-compaction-no-mglru+
6.8.0-rc1-folio-migration-free-page-split-no-mglru+
6.8.0-rc1-mm-eve 6.8.0-rc1-split-folio-in-co 6.8.0-rc1-folio-migration-i 6.8.0-rc1-folio-migration-f
---------------- --------------------------- --------------------------- ---------------------------
%stddev %change %stddev %change %stddev %change %stddev
\ | \ | \ | \
8065614 ± 3% +7.7% 8686626 ± 2% +5.0% 8467577 ± 4% +11.8% 9016077 ± 2% vm-scalability.throughput
=========================================================================================
compiler/kconfig/rootfs/runtime/tbox_group/test/testcase:
gcc-13/defconfig/debian/300s/qemu-vm/lru-file-mmap-read/vm-scalability
commit:
6.8.0-rc1-mm-everything-2024-01-29-07-19-no-mglru+
6.8.0-rc1-split-folio-in-compaction-no-mglru+
6.8.0-rc1-folio-migration-in-compaction-no-mglru+
6.8.0-rc1-folio-migration-free-page-split-no-mglru+
6.8.0-rc1-mm-eve 6.8.0-rc1-split-folio-in-co 6.8.0-rc1-folio-migration-i 6.8.0-rc1-folio-migration-f
---------------- --------------------------- --------------------------- ---------------------------
%stddev %change %stddev %change %stddev %change %stddev
\ | \ | \ | \
6438422 ± 2% +27.5% 8206734 ± 2% +10.6% 7118390 +26.2% 8127192 ± 4% vm-scalability.throughput
Zi Yan (4):
mm/page_alloc: remove unused fpi_flags in free_pages_prepare()
mm/compaction: enable compacting >0 order folios.
mm/compaction: add support for >0 order folio memory compaction.
mm/compaction: optimize >0 order folio compaction with free page
split.
mm/compaction.c | 260 ++++++++++++++++++++++++++++++++----------------
mm/internal.h | 4 +-
mm/page_alloc.c | 12 +--
3 files changed, 186 insertions(+), 90 deletions(-)
--
2.43.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v7 1/4] mm/page_alloc: remove unused fpi_flags in free_pages_prepare()
2024-02-20 18:32 [PATCH v7 0/4] Enable >0 order folio memory compaction Zi Yan
@ 2024-02-20 18:32 ` Zi Yan
2024-02-20 18:32 ` [PATCH v7 2/4] mm/compaction: enable compacting >0 order folios Zi Yan
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Zi Yan @ 2024-02-20 18:32 UTC (permalink / raw)
To: linux-mm, linux-kernel
Cc: Zi Yan, Huang, Ying, Ryan Roberts, Andrew Morton,
Matthew Wilcox (Oracle),
David Hildenbrand, Yin, Fengwei, Yu Zhao, Vlastimil Babka,
Kirill A . Shutemov, Johannes Weiner, Baolin Wang, Kemeng Shi,
Mel Gorman, Rohan Puri, Mcgrof Chamberlain, Adam Manzanares,
Vishal Moola (Oracle)
From: Zi Yan <ziy@nvidia.com>
Commit 0a54864f8dfb ("kasan: remove PG_skip_kasan_poison flag") removes
the use of fpi_flags in should_skip_kasan_poison() and fpi_flags is only
passed to should_skip_kasan_poison() in free_pages_prepare(). Remove the
unused parameter.
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
---
mm/page_alloc.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7ae4b74c9e5c..70c1ed3addf3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1061,7 +1061,7 @@ static int free_tail_page_prepare(struct page *head_page, struct page *page)
* on-demand allocation and then freed again before the deferred pages
* initialization is done, but this is not likely to happen.
*/
-static inline bool should_skip_kasan_poison(struct page *page, fpi_t fpi_flags)
+static inline bool should_skip_kasan_poison(struct page *page)
{
if (IS_ENABLED(CONFIG_KASAN_GENERIC))
return deferred_pages_enabled();
@@ -1081,10 +1081,10 @@ static void kernel_init_pages(struct page *page, int numpages)
}
static __always_inline bool free_pages_prepare(struct page *page,
- unsigned int order, fpi_t fpi_flags)
+ unsigned int order)
{
int bad = 0;
- bool skip_kasan_poison = should_skip_kasan_poison(page, fpi_flags);
+ bool skip_kasan_poison = should_skip_kasan_poison(page);
bool init = want_init_on_free();
bool compound = PageCompound(page);
@@ -1266,7 +1266,7 @@ static void __free_pages_ok(struct page *page, unsigned int order,
unsigned long pfn = page_to_pfn(page);
struct zone *zone = page_zone(page);
- if (!free_pages_prepare(page, order, fpi_flags))
+ if (!free_pages_prepare(page, order))
return;
/*
@@ -2379,7 +2379,7 @@ static bool free_unref_page_prepare(struct page *page, unsigned long pfn,
{
int migratetype;
- if (!free_pages_prepare(page, order, FPI_NONE))
+ if (!free_pages_prepare(page, order))
return false;
migratetype = get_pfnblock_migratetype(page, pfn);
--
2.43.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v7 2/4] mm/compaction: enable compacting >0 order folios.
2024-02-20 18:32 [PATCH v7 0/4] Enable >0 order folio memory compaction Zi Yan
2024-02-20 18:32 ` [PATCH v7 1/4] mm/page_alloc: remove unused fpi_flags in free_pages_prepare() Zi Yan
@ 2024-02-20 18:32 ` Zi Yan
2024-02-20 18:32 ` [PATCH v7 3/4] mm/compaction: add support for >0 order folio memory compaction Zi Yan
2024-02-20 18:32 ` [PATCH v7 4/4] mm/compaction: optimize >0 order folio compaction with free page split Zi Yan
3 siblings, 0 replies; 5+ messages in thread
From: Zi Yan @ 2024-02-20 18:32 UTC (permalink / raw)
To: linux-mm, linux-kernel
Cc: Zi Yan, Huang, Ying, Ryan Roberts, Andrew Morton,
Matthew Wilcox (Oracle),
David Hildenbrand, Yin, Fengwei, Yu Zhao, Vlastimil Babka,
Kirill A . Shutemov, Johannes Weiner, Baolin Wang, Kemeng Shi,
Mel Gorman, Rohan Puri, Mcgrof Chamberlain, Adam Manzanares,
Vishal Moola (Oracle)
From: Zi Yan <ziy@nvidia.com>
migrate_pages() supports >0 order folio migration and during compaction,
even if compaction_alloc() cannot provide >0 order free pages,
migrate_pages() can split the source page and try to migrate the base
pages from the split. It can be a baseline and start point for adding
support for compacting >0 order folios.
Signed-off-by: Zi Yan <ziy@nvidia.com>
Suggested-by: Huang Ying <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Adam Manzanares <a.manzanares@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yin Fengwei <fengwei.yin@intel.com>
---
mm/compaction.c | 101 ++++++++++++++++++++++++++++++++++++------------
1 file changed, 76 insertions(+), 25 deletions(-)
diff --git a/mm/compaction.c b/mm/compaction.c
index ccd447282665..6509fab27be9 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -40,9 +40,22 @@ static inline void count_compact_events(enum vm_event_item item, long delta)
{
count_vm_events(item, delta);
}
+
+/*
+ * order == -1 is expected when compacting proactively via
+ * 1. /proc/sys/vm/compact_memory
+ * 2. /sys/devices/system/node/nodex/compact
+ * 3. /proc/sys/vm/compaction_proactiveness
+ */
+static inline bool is_via_compact_memory(int order)
+{
+ return order == -1;
+}
+
#else
#define count_compact_event(item) do { } while (0)
#define count_compact_events(item, delta) do { } while (0)
+static inline bool is_via_compact_memory(int order) { return false; }
#endif
#if defined CONFIG_COMPACTION || defined CONFIG_CMA
@@ -816,6 +829,32 @@ static bool too_many_isolated(struct compact_control *cc)
return too_many;
}
+/**
+ * skip_isolation_on_order() - determine when to skip folio isolation based on
+ * folio order and compaction target order
+ * @order: to-be-isolated folio order
+ * @target_order: compaction target order
+ *
+ * This avoids unnecessary folio isolations during compaction.
+ */
+static bool skip_isolation_on_order(int order, int target_order)
+{
+ /*
+ * Unless we are performing global compaction (i.e.,
+ * is_via_compact_memory), skip any folios that are larger than the
+ * target order: we wouldn't be here if we'd have a free folio with
+ * the desired target_order, so migrating this folio would likely fail
+ * later.
+ */
+ if (!is_via_compact_memory(target_order) && order >= target_order)
+ return true;
+ /*
+ * We limit memory compaction to pageblocks and won't try
+ * creating free blocks of memory that are larger than that.
+ */
+ return order >= pageblock_order;
+}
+
/**
* isolate_migratepages_block() - isolate all migrate-able pages within
* a single pageblock
@@ -947,7 +986,22 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
valid_page = page;
}
- if (PageHuge(page) && cc->alloc_contig) {
+ if (PageHuge(page)) {
+ /*
+ * skip hugetlbfs if we are not compacting for pages
+ * bigger than its order. THPs and other compound pages
+ * are handled below.
+ */
+ if (!cc->alloc_contig) {
+ const unsigned int order = compound_order(page);
+
+ if (order <= MAX_PAGE_ORDER) {
+ low_pfn += (1UL << order) - 1;
+ nr_scanned += (1UL << order) - 1;
+ }
+ goto isolate_fail;
+ }
+ /* for alloc_contig case */
if (locked) {
unlock_page_lruvec_irqrestore(locked, flags);
locked = NULL;
@@ -1008,21 +1062,24 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
}
/*
- * Regardless of being on LRU, compound pages such as THP and
- * hugetlbfs are not to be compacted unless we are attempting
- * an allocation much larger than the huge page size (eg CMA).
- * We can potentially save a lot of iterations if we skip them
- * at once. The check is racy, but we can consider only valid
- * values and the only danger is skipping too much.
+ * Regardless of being on LRU, compound pages such as THP
+ * (hugetlbfs is handled above) are not to be compacted unless
+ * we are attempting an allocation larger than the compound
+ * page size. We can potentially save a lot of iterations if we
+ * skip them at once. The check is racy, but we can consider
+ * only valid values and the only danger is skipping too much.
*/
if (PageCompound(page) && !cc->alloc_contig) {
const unsigned int order = compound_order(page);
- if (likely(order <= MAX_PAGE_ORDER)) {
- low_pfn += (1UL << order) - 1;
- nr_scanned += (1UL << order) - 1;
+ /* Skip based on page order and compaction target order. */
+ if (skip_isolation_on_order(order, cc->order)) {
+ if (order <= MAX_PAGE_ORDER) {
+ low_pfn += (1UL << order) - 1;
+ nr_scanned += (1UL << order) - 1;
+ }
+ goto isolate_fail;
}
- goto isolate_fail;
}
/*
@@ -1165,10 +1222,11 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
}
/*
- * folio become large since the non-locked check,
- * and it's on LRU.
+ * Check LRU folio order under the lock
*/
- if (unlikely(folio_test_large(folio) && !cc->alloc_contig)) {
+ if (unlikely(skip_isolation_on_order(folio_order(folio),
+ cc->order) &&
+ !cc->alloc_contig)) {
low_pfn += folio_nr_pages(folio) - 1;
nr_scanned += folio_nr_pages(folio) - 1;
folio_set_lru(folio);
@@ -1788,6 +1846,10 @@ static struct folio *compaction_alloc(struct folio *src, unsigned long data)
struct compact_control *cc = (struct compact_control *)data;
struct folio *dst;
+ /* this makes migrate_pages() split the source page and retry */
+ if (folio_test_large(src))
+ return NULL;
+
if (list_empty(&cc->freepages)) {
isolate_freepages(cc);
@@ -2090,17 +2152,6 @@ static isolate_migrate_t isolate_migratepages(struct compact_control *cc)
return cc->nr_migratepages ? ISOLATE_SUCCESS : ISOLATE_NONE;
}
-/*
- * order == -1 is expected when compacting proactively via
- * 1. /proc/sys/vm/compact_memory
- * 2. /sys/devices/system/node/nodex/compact
- * 3. /proc/sys/vm/compaction_proactiveness
- */
-static inline bool is_via_compact_memory(int order)
-{
- return order == -1;
-}
-
/*
* Determine whether kswapd is (or recently was!) running on this node.
*
--
2.43.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v7 3/4] mm/compaction: add support for >0 order folio memory compaction.
2024-02-20 18:32 [PATCH v7 0/4] Enable >0 order folio memory compaction Zi Yan
2024-02-20 18:32 ` [PATCH v7 1/4] mm/page_alloc: remove unused fpi_flags in free_pages_prepare() Zi Yan
2024-02-20 18:32 ` [PATCH v7 2/4] mm/compaction: enable compacting >0 order folios Zi Yan
@ 2024-02-20 18:32 ` Zi Yan
2024-02-20 18:32 ` [PATCH v7 4/4] mm/compaction: optimize >0 order folio compaction with free page split Zi Yan
3 siblings, 0 replies; 5+ messages in thread
From: Zi Yan @ 2024-02-20 18:32 UTC (permalink / raw)
To: linux-mm, linux-kernel
Cc: Zi Yan, Huang, Ying, Ryan Roberts, Andrew Morton,
Matthew Wilcox (Oracle),
David Hildenbrand, Yin, Fengwei, Yu Zhao, Vlastimil Babka,
Kirill A . Shutemov, Johannes Weiner, Baolin Wang, Kemeng Shi,
Mel Gorman, Rohan Puri, Mcgrof Chamberlain, Adam Manzanares,
Vishal Moola (Oracle)
From: Zi Yan <ziy@nvidia.com>
Before last commit, memory compaction only migrates order-0 folios and
skips >0 order folios. Last commit splits all >0 order folios during
compaction. This commit migrates >0 order folios during compaction by
keeping isolated free pages at their original size without splitting them
into order-0 pages and using them directly during migration process.
What is different from the prior implementation:
1. All isolated free pages are kept in a NR_PAGE_ORDERS array of page
lists, where each page list stores free pages in the same order.
2. All free pages are not post_alloc_hook() processed nor buddy pages,
although their orders are stored in first page's private like buddy
pages.
3. During migration, in new page allocation time (i.e., in
compaction_alloc()), free pages are then processed by post_alloc_hook().
When migration fails and a new page is returned (i.e., in
compaction_free()), free pages are restored by reversing the
post_alloc_hook() operations using newly added
free_pages_prepare_fpi_none().
Step 3 is done for a latter optimization that splitting and/or merging
free pages during compaction becomes easier.
Note: without splitting free pages, compaction can end prematurely due to
migration will return -ENOMEM even if there is free pages. This happens
when no order-0 free page exist and compaction_alloc() return NULL.
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Adam Manzanares <a.manzanares@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yin Fengwei <fengwei.yin@intel.com>
---
mm/compaction.c | 140 +++++++++++++++++++++++++++---------------------
mm/internal.h | 4 +-
mm/page_alloc.c | 2 +-
3 files changed, 83 insertions(+), 63 deletions(-)
diff --git a/mm/compaction.c b/mm/compaction.c
index 6509fab27be9..112711752321 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -79,45 +79,56 @@ static inline bool is_via_compact_memory(int order) { return false; }
#define COMPACTION_HPAGE_ORDER (PMD_SHIFT - PAGE_SHIFT)
#endif
-static unsigned long release_freepages(struct list_head *freelist)
+static void split_map_pages(struct list_head *freepages)
{
+ unsigned int i, order;
struct page *page, *next;
- unsigned long high_pfn = 0;
+ LIST_HEAD(tmp_list);
- list_for_each_entry_safe(page, next, freelist, lru) {
- unsigned long pfn = page_to_pfn(page);
- list_del(&page->lru);
- __free_page(page);
- if (pfn > high_pfn)
- high_pfn = pfn;
- }
+ for (order = 0; order < NR_PAGE_ORDERS; order++) {
+ list_for_each_entry_safe(page, next, &freepages[order], lru) {
+ unsigned int nr_pages;
- return high_pfn;
+ list_del(&page->lru);
+
+ nr_pages = 1 << order;
+
+ post_alloc_hook(page, order, __GFP_MOVABLE);
+ if (order)
+ split_page(page, order);
+
+ for (i = 0; i < nr_pages; i++) {
+ list_add(&page->lru, &tmp_list);
+ page++;
+ }
+ }
+ list_splice_init(&tmp_list, &freepages[0]);
+ }
}
-static void split_map_pages(struct list_head *list)
+static unsigned long release_free_list(struct list_head *freepages)
{
- unsigned int i, order, nr_pages;
- struct page *page, *next;
- LIST_HEAD(tmp_list);
-
- list_for_each_entry_safe(page, next, list, lru) {
- list_del(&page->lru);
+ int order;
+ unsigned long high_pfn = 0;
- order = page_private(page);
- nr_pages = 1 << order;
+ for (order = 0; order < NR_PAGE_ORDERS; order++) {
+ struct page *page, *next;
- post_alloc_hook(page, order, __GFP_MOVABLE);
- if (order)
- split_page(page, order);
+ list_for_each_entry_safe(page, next, &freepages[order], lru) {
+ unsigned long pfn = page_to_pfn(page);
- for (i = 0; i < nr_pages; i++) {
- list_add(&page->lru, &tmp_list);
- page++;
+ list_del(&page->lru);
+ /*
+ * Convert free pages into post allocation pages, so
+ * that we can free them via __free_page.
+ */
+ post_alloc_hook(page, order, __GFP_MOVABLE);
+ __free_pages(page, order);
+ if (pfn > high_pfn)
+ high_pfn = pfn;
}
}
-
- list_splice(&tmp_list, list);
+ return high_pfn;
}
#ifdef CONFIG_COMPACTION
@@ -670,7 +681,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
nr_scanned += isolated - 1;
total_isolated += isolated;
cc->nr_freepages += isolated;
- list_add_tail(&page->lru, freelist);
+ list_add_tail(&page->lru, &freelist[order]);
if (!strict && cc->nr_migratepages <= cc->nr_freepages) {
blockpfn += isolated;
@@ -735,7 +746,11 @@ isolate_freepages_range(struct compact_control *cc,
unsigned long start_pfn, unsigned long end_pfn)
{
unsigned long isolated, pfn, block_start_pfn, block_end_pfn;
- LIST_HEAD(freelist);
+ int order;
+ struct list_head tmp_freepages[NR_PAGE_ORDERS];
+
+ for (order = 0; order < NR_PAGE_ORDERS; order++)
+ INIT_LIST_HEAD(&tmp_freepages[order]);
pfn = start_pfn;
block_start_pfn = pageblock_start_pfn(pfn);
@@ -766,7 +781,7 @@ isolate_freepages_range(struct compact_control *cc,
break;
isolated = isolate_freepages_block(cc, &isolate_start_pfn,
- block_end_pfn, &freelist, 0, true);
+ block_end_pfn, tmp_freepages, 0, true);
/*
* In strict mode, isolate_freepages_block() returns 0 if
@@ -783,15 +798,15 @@ isolate_freepages_range(struct compact_control *cc,
*/
}
- /* __isolate_free_page() does not map the pages */
- split_map_pages(&freelist);
-
if (pfn < end_pfn) {
/* Loop terminated early, cleanup. */
- release_freepages(&freelist);
+ release_free_list(tmp_freepages);
return 0;
}
+ /* __isolate_free_page() does not map the pages */
+ split_map_pages(tmp_freepages);
+
/* We don't use freelists for anything. */
return pfn;
}
@@ -1518,7 +1533,7 @@ fast_isolate_around(struct compact_control *cc, unsigned long pfn)
if (!page)
return;
- isolate_freepages_block(cc, &start_pfn, end_pfn, &cc->freepages, 1, false);
+ isolate_freepages_block(cc, &start_pfn, end_pfn, cc->freepages, 1, false);
/* Skip this pageblock in the future as it's full or nearly full */
if (start_pfn == end_pfn && !cc->no_set_skip_hint)
@@ -1647,7 +1662,7 @@ static void fast_isolate_freepages(struct compact_control *cc)
nr_scanned += nr_isolated - 1;
total_isolated += nr_isolated;
cc->nr_freepages += nr_isolated;
- list_add_tail(&page->lru, &cc->freepages);
+ list_add_tail(&page->lru, &cc->freepages[order]);
count_compact_events(COMPACTISOLATED, nr_isolated);
} else {
/* If isolation fails, abort the search */
@@ -1724,13 +1739,12 @@ static void isolate_freepages(struct compact_control *cc)
unsigned long isolate_start_pfn; /* exact pfn we start at */
unsigned long block_end_pfn; /* end of current pageblock */
unsigned long low_pfn; /* lowest pfn scanner is able to scan */
- struct list_head *freelist = &cc->freepages;
unsigned int stride;
/* Try a small search of the free lists for a candidate */
fast_isolate_freepages(cc);
if (cc->nr_freepages)
- goto splitmap;
+ return;
/*
* Initialise the free scanner. The starting point is where we last
@@ -1790,7 +1804,7 @@ static void isolate_freepages(struct compact_control *cc)
/* Found a block suitable for isolating free pages from. */
nr_isolated = isolate_freepages_block(cc, &isolate_start_pfn,
- block_end_pfn, freelist, stride, false);
+ block_end_pfn, cc->freepages, stride, false);
/* Update the skip hint if the full pageblock was scanned */
if (isolate_start_pfn == block_end_pfn)
@@ -1831,10 +1845,6 @@ static void isolate_freepages(struct compact_control *cc)
* and the loop terminated due to isolate_start_pfn < low_pfn
*/
cc->free_pfn = isolate_start_pfn;
-
-splitmap:
- /* __isolate_free_page() does not map the pages */
- split_map_pages(freelist);
}
/*
@@ -1845,24 +1855,22 @@ static struct folio *compaction_alloc(struct folio *src, unsigned long data)
{
struct compact_control *cc = (struct compact_control *)data;
struct folio *dst;
+ int order = folio_order(src);
- /* this makes migrate_pages() split the source page and retry */
- if (folio_test_large(src))
- return NULL;
-
- if (list_empty(&cc->freepages)) {
+ if (list_empty(&cc->freepages[order])) {
isolate_freepages(cc);
-
- if (list_empty(&cc->freepages))
+ if (list_empty(&cc->freepages[order]))
return NULL;
}
- dst = list_entry(cc->freepages.next, struct folio, lru);
+ dst = list_first_entry(&cc->freepages[order], struct folio, lru);
list_del(&dst->lru);
- cc->nr_freepages--;
- cc->nr_migratepages--;
-
- return dst;
+ post_alloc_hook(&dst->page, order, __GFP_MOVABLE);
+ if (order)
+ prep_compound_page(&dst->page, order);
+ cc->nr_freepages -= 1 << order;
+ cc->nr_migratepages -= 1 << order;
+ return page_rmappable_folio(&dst->page);
}
/*
@@ -1873,10 +1881,19 @@ static struct folio *compaction_alloc(struct folio *src, unsigned long data)
static void compaction_free(struct folio *dst, unsigned long data)
{
struct compact_control *cc = (struct compact_control *)data;
+ int order = folio_order(dst);
+ struct page *page = &dst->page;
- list_add(&dst->lru, &cc->freepages);
- cc->nr_freepages++;
- cc->nr_migratepages++;
+ if (folio_put_testzero(dst)) {
+ free_pages_prepare(page, order);
+ list_add(&dst->lru, &cc->freepages[order]);
+ cc->nr_freepages += 1 << order;
+ }
+ cc->nr_migratepages += 1 << order;
+ /*
+ * someone else has referenced the page, we cannot take it back to our
+ * free list.
+ */
}
/* possible outcome of isolate_migratepages */
@@ -2489,6 +2506,7 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
const bool sync = cc->mode != MIGRATE_ASYNC;
bool update_cached;
unsigned int nr_succeeded = 0;
+ int order;
/*
* These counters track activities during zone compaction. Initialize
@@ -2498,7 +2516,8 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
cc->total_free_scanned = 0;
cc->nr_migratepages = 0;
cc->nr_freepages = 0;
- INIT_LIST_HEAD(&cc->freepages);
+ for (order = 0; order < NR_PAGE_ORDERS; order++)
+ INIT_LIST_HEAD(&cc->freepages[order]);
INIT_LIST_HEAD(&cc->migratepages);
cc->migratetype = gfp_migratetype(cc->gfp_mask);
@@ -2684,7 +2703,7 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
* so we don't leave any returned pages behind in the next attempt.
*/
if (cc->nr_freepages > 0) {
- unsigned long free_pfn = release_freepages(&cc->freepages);
+ unsigned long free_pfn = release_free_list(cc->freepages);
cc->nr_freepages = 0;
VM_BUG_ON(free_pfn == 0);
@@ -2703,7 +2722,6 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
trace_mm_compaction_end(cc, start_pfn, end_pfn, sync, ret);
- VM_BUG_ON(!list_empty(&cc->freepages));
VM_BUG_ON(!list_empty(&cc->migratepages));
return ret;
diff --git a/mm/internal.h b/mm/internal.h
index 1e29c5821a1d..93e229112045 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -447,6 +447,8 @@ extern void prep_compound_page(struct page *page, unsigned int order);
extern void post_alloc_hook(struct page *page, unsigned int order,
gfp_t gfp_flags);
+extern bool free_pages_prepare(struct page *page, unsigned int order);
+
extern int user_min_free_kbytes;
extern void free_unref_page(struct page *page, unsigned int order);
@@ -481,7 +483,7 @@ int split_free_page(struct page *free_page,
* completes when free_pfn <= migrate_pfn
*/
struct compact_control {
- struct list_head freepages; /* List of free pages to migrate to */
+ struct list_head freepages[NR_PAGE_ORDERS]; /* List of free pages to migrate to */
struct list_head migratepages; /* List of pages being migrated */
unsigned int nr_freepages; /* Number of isolated free pages */
unsigned int nr_migratepages; /* Number of pages to migrate */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 70c1ed3addf3..b0b92ce997dc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1080,7 +1080,7 @@ static void kernel_init_pages(struct page *page, int numpages)
kasan_enable_current();
}
-static __always_inline bool free_pages_prepare(struct page *page,
+__always_inline bool free_pages_prepare(struct page *page,
unsigned int order)
{
int bad = 0;
--
2.43.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v7 4/4] mm/compaction: optimize >0 order folio compaction with free page split.
2024-02-20 18:32 [PATCH v7 0/4] Enable >0 order folio memory compaction Zi Yan
` (2 preceding siblings ...)
2024-02-20 18:32 ` [PATCH v7 3/4] mm/compaction: add support for >0 order folio memory compaction Zi Yan
@ 2024-02-20 18:32 ` Zi Yan
3 siblings, 0 replies; 5+ messages in thread
From: Zi Yan @ 2024-02-20 18:32 UTC (permalink / raw)
To: linux-mm, linux-kernel
Cc: Zi Yan, Huang, Ying, Ryan Roberts, Andrew Morton,
Matthew Wilcox (Oracle),
David Hildenbrand, Yin, Fengwei, Yu Zhao, Vlastimil Babka,
Kirill A . Shutemov, Johannes Weiner, Baolin Wang, Kemeng Shi,
Mel Gorman, Rohan Puri, Mcgrof Chamberlain, Adam Manzanares,
Vishal Moola (Oracle)
From: Zi Yan <ziy@nvidia.com>
During migration in a memory compaction, free pages are placed in an array
of page lists based on their order. But the desired free page order
(i.e., the order of a source page) might not be always present, thus
leading to migration failures and premature compaction termination. Split
a high order free pages when source migration page has a lower order to
increase migration successful rate.
Note: merging free pages when a migration fails and a lower order free
page is returned via compaction_free() is possible, but there is too much
work. Since the free pages are not buddy pages, it is hard to identify
these free pages using existing PFN-based page merging algorithm.
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Adam Manzanares <a.manzanares@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yin Fengwei <fengwei.yin@intel.com>
---
mm/compaction.c | 35 ++++++++++++++++++++++++++++++-----
1 file changed, 30 insertions(+), 5 deletions(-)
diff --git a/mm/compaction.c b/mm/compaction.c
index 112711752321..e70309674262 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1856,15 +1856,40 @@ static struct folio *compaction_alloc(struct folio *src, unsigned long data)
struct compact_control *cc = (struct compact_control *)data;
struct folio *dst;
int order = folio_order(src);
+ bool has_isolated_pages = false;
+ int start_order;
+ struct page *freepage;
+ unsigned long size;
+
+again:
+ for (start_order = order; start_order < NR_PAGE_ORDERS; start_order++)
+ if (!list_empty(&cc->freepages[start_order]))
+ break;
- if (list_empty(&cc->freepages[order])) {
- isolate_freepages(cc);
- if (list_empty(&cc->freepages[order]))
+ /* no free pages in the list */
+ if (start_order == NR_PAGE_ORDERS) {
+ if (has_isolated_pages)
return NULL;
+ isolate_freepages(cc);
+ has_isolated_pages = true;
+ goto again;
+ }
+
+ freepage = list_first_entry(&cc->freepages[start_order], struct page,
+ lru);
+ size = 1 << start_order;
+
+ list_del(&freepage->lru);
+
+ while (start_order > order) {
+ start_order--;
+ size >>= 1;
+
+ list_add(&freepage[size].lru, &cc->freepages[start_order]);
+ set_page_private(&freepage[size], start_order);
}
+ dst = (struct folio *)freepage;
- dst = list_first_entry(&cc->freepages[order], struct folio, lru);
- list_del(&dst->lru);
post_alloc_hook(&dst->page, order, __GFP_MOVABLE);
if (order)
prep_compound_page(&dst->page, order);
--
2.43.0
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2024-02-20 18:32 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2024-02-20 18:32 [PATCH v7 0/4] Enable >0 order folio memory compaction Zi Yan
2024-02-20 18:32 ` [PATCH v7 1/4] mm/page_alloc: remove unused fpi_flags in free_pages_prepare() Zi Yan
2024-02-20 18:32 ` [PATCH v7 2/4] mm/compaction: enable compacting >0 order folios Zi Yan
2024-02-20 18:32 ` [PATCH v7 3/4] mm/compaction: add support for >0 order folio memory compaction Zi Yan
2024-02-20 18:32 ` [PATCH v7 4/4] mm/compaction: optimize >0 order folio compaction with free page split Zi Yan
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