From: Michal Nazarewicz mina86@mina86.com
This commit introduces isolate_migratepages_range() function which extracts functionality from isolate_migratepages() so that it can be used on arbitrary PFN ranges.
isolate_migratepages() function is implemented as a simple wrapper around isolate_migratepages_range().
Signed-off-by: Michal Nazarewicz mina86@mina86.com Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com --- mm/compaction.c | 77 +++++++++++++++++++++++++++++++++++++++--------------- 1 files changed, 55 insertions(+), 22 deletions(-)
diff --git a/mm/compaction.c b/mm/compaction.c index 71a58f6..a42bbdd 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -250,31 +250,34 @@ typedef enum { ISOLATE_SUCCESS, /* Pages isolated, migrate */ } isolate_migrate_t;
-/* - * Isolate all pages that can be migrated from the block pointed to by - * the migrate scanner within compact_control. +/** + * isolate_migratepages_range() - isolate all migrate-able pages in range. + * @zone: Zone pages are in. + * @cc: Compaction control structure. + * @low_pfn: The first PFN of the range. + * @end_pfn: The one-past-the-last PFN of the range. + * + * Isolate all pages that can be migrated from the range specified by + * [low_pfn, end_pfn). Returns zero if there is a fatal signal + * pending), otherwise PFN of the first page that was not scanned + * (which may be both less, equal to or more then end_pfn). + * + * Assumes that cc->migratepages is empty and cc->nr_migratepages is + * zero. + * + * Apart from cc->migratepages and cc->nr_migratetypes this function + * does not modify any cc's fields, in particular it does not modify + * (or read for that matter) cc->migrate_pfn. */ -static isolate_migrate_t isolate_migratepages(struct zone *zone, - struct compact_control *cc) +static unsigned long +isolate_migratepages_range(struct zone *zone, struct compact_control *cc, + unsigned long low_pfn, unsigned long end_pfn) { - unsigned long low_pfn, end_pfn; unsigned long last_pageblock_nr = 0, pageblock_nr; unsigned long nr_scanned = 0, nr_isolated = 0; struct list_head *migratelist = &cc->migratepages; isolate_mode_t mode = ISOLATE_ACTIVE|ISOLATE_INACTIVE;
- /* Do not scan outside zone boundaries */ - low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn); - - /* Only scan within a pageblock boundary */ - end_pfn = ALIGN(low_pfn + pageblock_nr_pages, pageblock_nr_pages); - - /* Do not cross the free scanner or scan within a memory hole */ - if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) { - cc->migrate_pfn = end_pfn; - return ISOLATE_NONE; - } - /* * Ensure that there are not too many pages isolated from the LRU * list by either parallel reclaimers or compaction. If there are, @@ -283,12 +286,12 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, while (unlikely(too_many_isolated(zone))) { /* async migration should just abort */ if (!cc->sync) - return ISOLATE_ABORT; + return 0;
congestion_wait(BLK_RW_ASYNC, HZ/10);
if (fatal_signal_pending(current)) - return ISOLATE_ABORT; + return 0; }
/* Time to isolate some pages for migration */ @@ -313,7 +316,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, } else if (!locked) spin_lock_irq(&zone->lru_lock);
- if (!pfn_valid_within(low_pfn)) + if (!pfn_valid(low_pfn)) continue; nr_scanned++;
@@ -374,10 +377,40 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, acct_isolated(zone, cc);
spin_unlock_irq(&zone->lru_lock); - cc->migrate_pfn = low_pfn;
trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated);
+ return low_pfn; +} + +/* + * Isolate all pages that can be migrated from the block pointed to by + * the migrate scanner within compact_control. + */ +static isolate_migrate_t isolate_migratepages(struct zone *zone, + struct compact_control *cc) +{ + unsigned long low_pfn, end_pfn; + + /* Do not scan outside zone boundaries */ + low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn); + + /* Only scan within a pageblock boundary */ + end_pfn = ALIGN(low_pfn + pageblock_nr_pages, pageblock_nr_pages); + + /* Do not cross the free scanner or scan within a memory hole */ + if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) { + cc->migrate_pfn = end_pfn; + return ISOLATE_NONE; + } + + /* Perform the isolation */ + low_pfn = isolate_migratepages_range(zone, cc, low_pfn, end_pfn); + if (!low_pfn) + return ISOLATE_ABORT; + + cc->migrate_pfn = low_pfn; + return ISOLATE_SUCCESS; }