* [merged] revert-mm-have-order-0-compaction-start-off-where-it-left.patch removed from -mm tree
@ 2012-10-09 18:12 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2012-10-09 18:12 UTC (permalink / raw)
To: mgorman, aquini, avi, minchan, richard, riel, shli, mm-commits
The patch titled
Subject: revert "mm: have order > 0 compaction start off where it left"
has been removed from the -mm tree. Its filename was
revert-mm-have-order-0-compaction-start-off-where-it-left.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Mel Gorman <mgorman@suse.de>
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@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Richard Davies <richard@arachsys.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Avi Kivity <avi@redhat.com>
Acked-by: Rafael Aquini <aquini@redhat.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
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
@@ -369,10 +369,6 @@ 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
@@ -538,20 +538,6 @@ 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.
*/
@@ -619,19 +605,8 @@ 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 */
@@ -639,11 +614,6 @@ 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;
}
/*
@@ -738,26 +708,8 @@ 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;
/*
@@ -863,15 +815,8 @@ 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
@@ -118,14 +118,8 @@ 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
@@ -4490,11 +4490,6 @@ 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@suse.de are
origin.patch
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2012-10-09 18:12 [merged] revert-mm-have-order-0-compaction-start-off-where-it-left.patch removed from -mm tree akpm
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