The patch titled
Subject: Revert "mm: have order > 0 compaction start off where it left"
has been added to the -mm tree. Its filename is
revert-mm-have-order-0-compaction-start-off-where-it-left.patch
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------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxx>
Subject: Revert "mm: have order > 0 compaction start off where it left"
This reverts commit 7db8889a ("mm: have order > 0 compaction start off
where it left") and commit de74f1cc ("mm: have order > 0 compaction start
near a pageblock with free pages"). These patches were a good idea and
tests confirmed that they massively reduced the amount of scanning but the
implementation is complex and tricky to understand. A later patch will
cache what pageblocks should be skipped and reimplements the concept of
compact_cached_free_pfn on top for both migration and free scanners.
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Richard Davies <richard@xxxxxxxxxxxx>
Cc: Shaohua Li <shli@xxxxxxxxxx>
Cc: Avi Kivity <avi@xxxxxxxxxx>
Acked-by: Rafael Aquini <aquini@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mmzone.h | 4 --
mm/compaction.c | 65 +++------------------------------------
mm/internal.h | 6 ---
mm/page_alloc.c | 5 ---
4 files changed, 5 insertions(+), 75 deletions(-)
diff -puN include/linux/mmzone.h~revert-mm-have-order-0-compaction-start-off-where-it-left include/linux/mmzone.h
--- a/include/linux/mmzone.h~revert-mm-have-order-0-compaction-start-off-where-it-left
+++ a/include/linux/mmzone.h
@@ -384,10 +384,6 @@ struct zone {
*/
spinlock_t lock;
int all_unreclaimable; /* All pages pinned */
-#if defined CONFIG_COMPACTION || defined CONFIG_CMA
- /* pfn where the last incremental compaction isolated free pages */
- unsigned long compact_cached_free_pfn;
-#endif
#ifdef CONFIG_MEMORY_HOTPLUG
/* see spanned/present_pages for more description */
seqlock_t span_seqlock;
diff -puN mm/compaction.c~revert-mm-have-order-0-compaction-start-off-where-it-left mm/compaction.c
--- a/mm/compaction.c~revert-mm-have-order-0-compaction-start-off-where-it-left
+++ a/mm/compaction.c
@@ -539,20 +539,6 @@ next_pageblock:
#endif /* CONFIG_COMPACTION || CONFIG_CMA */
#ifdef CONFIG_COMPACTION
/*
- * Returns the start pfn of the last page block in a zone. This is the starting
- * point for full compaction of a zone. Compaction searches for free pages from
- * the end of each zone, while isolate_freepages_block scans forward inside each
- * page block.
- */
-static unsigned long start_free_pfn(struct zone *zone)
-{
- unsigned long free_pfn;
- free_pfn = zone->zone_start_pfn + zone->spanned_pages;
- free_pfn &= ~(pageblock_nr_pages-1);
- return free_pfn;
-}
-
-/*
* Based on information in the current compact_control, find blocks
* suitable for isolating free pages from and then isolate them.
*/
@@ -620,19 +606,8 @@ static void isolate_freepages(struct zon
* looking for free pages, the search will restart here as
* page migration may have returned some pages to the allocator
*/
- if (isolated) {
+ if (isolated)
high_pfn = max(high_pfn, pfn);
-
- /*
- * If the free scanner has wrapped, update
- * compact_cached_free_pfn to point to the highest
- * pageblock with free pages. This reduces excessive
- * scanning of full pageblocks near the end of the
- * zone
- */
- if (cc->order > 0 && cc->wrapped)
- zone->compact_cached_free_pfn = high_pfn;
- }
}
/* split_free_page does not map the pages */
@@ -640,11 +615,6 @@ static void isolate_freepages(struct zon
cc->free_pfn = high_pfn;
cc->nr_freepages = nr_freepages;
-
- /* If compact_cached_free_pfn is reset then set it now */
- if (cc->order > 0 && !cc->wrapped &&
- zone->compact_cached_free_pfn == start_free_pfn(zone))
- zone->compact_cached_free_pfn = high_pfn;
}
/*
@@ -739,26 +709,8 @@ static int compact_finished(struct zone
if (fatal_signal_pending(current))
return COMPACT_PARTIAL;
- /*
- * A full (order == -1) compaction run starts at the beginning and
- * end of a zone; it completes when the migrate and free scanner meet.
- * A partial (order > 0) compaction can start with the free scanner
- * at a random point in the zone, and may have to restart.
- */
- if (cc->free_pfn <= cc->migrate_pfn) {
- if (cc->order > 0 && !cc->wrapped) {
- /* We started partway through; restart at the end. */
- unsigned long free_pfn = start_free_pfn(zone);
- zone->compact_cached_free_pfn = free_pfn;
- cc->free_pfn = free_pfn;
- cc->wrapped = 1;
- return COMPACT_CONTINUE;
- }
- return COMPACT_COMPLETE;
- }
-
- /* We wrapped around and ended up where we started. */
- if (cc->wrapped && cc->free_pfn <= cc->start_free_pfn)
+ /* Compaction run completes if the migrate and free scanner meet */
+ if (cc->free_pfn <= cc->migrate_pfn)
return COMPACT_COMPLETE;
/*
@@ -864,15 +816,8 @@ static int compact_zone(struct zone *zon
/* Setup to move all movable pages to the end of the zone */
cc->migrate_pfn = zone->zone_start_pfn;
-
- if (cc->order > 0) {
- /* Incremental compaction. Start where the last one stopped. */
- cc->free_pfn = zone->compact_cached_free_pfn;
- cc->start_free_pfn = cc->free_pfn;
- } else {
- /* Order == -1 starts at the end of the zone. */
- cc->free_pfn = start_free_pfn(zone);
- }
+ cc->free_pfn = cc->migrate_pfn + zone->spanned_pages;
+ cc->free_pfn &= ~(pageblock_nr_pages-1);
migrate_prep_local();
diff -puN mm/internal.h~revert-mm-have-order-0-compaction-start-off-where-it-left mm/internal.h
--- a/mm/internal.h~revert-mm-have-order-0-compaction-start-off-where-it-left
+++ a/mm/internal.h
@@ -119,14 +119,8 @@ struct compact_control {
unsigned long nr_freepages; /* Number of isolated free pages */
unsigned long nr_migratepages; /* Number of pages to migrate */
unsigned long free_pfn; /* isolate_freepages search base */
- unsigned long start_free_pfn; /* where we started the search */
unsigned long migrate_pfn; /* isolate_migratepages search base */
bool sync; /* Synchronous migration */
- bool wrapped; /* Order > 0 compactions are
- incremental, once free_pfn
- and migrate_pfn meet, we restart
- from the top of the zone;
- remember we wrapped around. */
int order; /* order a direct compactor needs */
int migratetype; /* MOVABLE, RECLAIMABLE etc */
diff -puN mm/page_alloc.c~revert-mm-have-order-0-compaction-start-off-where-it-left mm/page_alloc.c
--- a/mm/page_alloc.c~revert-mm-have-order-0-compaction-start-off-where-it-left
+++ a/mm/page_alloc.c
@@ -4488,11 +4488,6 @@ static void __paginginit free_area_init_
zone->spanned_pages = size;
zone->present_pages = realsize;
-#if defined CONFIG_COMPACTION || defined CONFIG_CMA
- zone->compact_cached_free_pfn = zone->zone_start_pfn +
- zone->spanned_pages;
- zone->compact_cached_free_pfn &= ~(pageblock_nr_pages-1);
-#endif
#ifdef CONFIG_NUMA
zone->node = nid;
zone->min_unmapped_pages = (realsize*sysctl_min_unmapped_ratio)
_
Patches currently in -mm which might be from mgorman@xxxxxxx are
origin.patch
mm-remove-__gfp_no_kswapd.patch
mm-compaction-update-comment-in-try_to_compact_pages.patch
mm-vmscan-scale-number-of-pages-reclaimed-by-reclaim-compaction-based-on-failures.patch
mm-vmscan-scale-number-of-pages-reclaimed-by-reclaim-compaction-based-on-failures-fix.patch
mm-compaction-capture-a-suitable-high-order-page-immediately-when-it-is-made-available.patch
revert-mm-mempolicy-let-vma_merge-and-vma_split-handle-vma-vm_policy-linkages.patch
mempolicy-remove-mempolicy-sharing.patch
mempolicy-fix-a-race-in-shared_policy_replace.patch
mempolicy-fix-refcount-leak-in-mpol_set_shared_policy.patch
mempolicy-fix-a-memory-corruption-by-refcount-imbalance-in-alloc_pages_vma.patch
mempolicy-fix-a-memory-corruption-by-refcount-imbalance-in-alloc_pages_vma-v2.patch
mm-cma-discard-clean-pages-during-contiguous-allocation-instead-of-migration.patch
mm-cma-discard-clean-pages-during-contiguous-allocation-instead-of-migration-fix.patch
mm-fix-tracing-in-free_pcppages_bulk.patch
mm-fix-tracing-in-free_pcppages_bulk-fix.patch
cma-fix-counting-of-isolated-pages.patch
cma-count-free-cma-pages.patch
cma-count-free-cma-pages-fix.patch
cma-fix-watermark-checking.patch
mm-page_alloc-use-get_freepage_migratetype-instead-of-page_private.patch
mm-remain-migratetype-in-freed-page.patch
memory-hotplug-bug-fix-race-between-isolation-and-allocation.patch
memory-hotplug-fix-pages-missed-by-race-rather-than-failing.patch
mm-compaction-abort-compaction-loop-if-lock-is-contended-or-run-too-long.patch
mm-compaction-abort-compaction-loop-if-lock-is-contended-or-run-too-long-fix.patch
mm-compaction-abort-compaction-loop-if-lock-is-contended-or-run-too-long-fix-2.patch
mm-compaction-move-fatal-signal-check-out-of-compact_checklock_irqsave.patch
mm-compaction-update-try_to_compact_pageskerneldoc-comment.patch
mm-compaction-acquire-the-zone-lru_lock-as-late-as-possible.patch
mm-compaction-acquire-the-zone-lock-as-late-as-possible.patch
revert-mm-have-order-0-compaction-start-off-where-it-left.patch
mm-compaction-cache-if-a-pageblock-was-scanned-and-no-pages-were-isolated.patch
mm-compaction-restart-compaction-from-near-where-it-left-off.patch
mm-numa-reclaim-from-all-nodes-within-reclaim-distance.patch
mm-numa-reclaim-from-all-nodes-within-reclaim-distance-fix.patch
mm-thp-fix-pmd_present-for-split_huge_page-and-prot_none-with-thp.patch
mm-revert-0def08e3-mm-mempolicyc-check-return-code-of-check_range.patch
mm-revert-0def08e3-mm-mempolicyc-check-return-code-of-check_range-fix.patch
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