diff options
| -rw-r--r-- | mm/compaction.c | 39 |
1 files changed, 30 insertions, 9 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index 5039c964f5c8..b69b7dac0361 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -330,7 +330,7 @@ static bool suitable_migration_target(struct page *page) * (even though it may still end up isolating some pages). */ static unsigned long isolate_freepages_block(struct compact_control *cc, - unsigned long blockpfn, + unsigned long *start_pfn, unsigned long end_pfn, struct list_head *freelist, bool strict) @@ -339,6 +339,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, struct page *cursor, *valid_page = NULL; unsigned long flags; bool locked = false; + unsigned long blockpfn = *start_pfn; cursor = pfn_to_page(blockpfn); @@ -415,6 +416,9 @@ isolate_fail: } + /* Record how far we have got within the block */ + *start_pfn = blockpfn; + trace_mm_compaction_isolate_freepages(nr_scanned, total_isolated); /* @@ -463,14 +467,16 @@ isolate_freepages_range(struct compact_control *cc, for (; pfn < end_pfn; pfn += isolated, block_end_pfn += pageblock_nr_pages) { + /* Protect pfn from changing by isolate_freepages_block */ + unsigned long isolate_start_pfn = pfn; block_end_pfn = min(block_end_pfn, end_pfn); if (!pageblock_pfn_to_page(pfn, block_end_pfn, cc->zone)) break; - isolated = isolate_freepages_block(cc, pfn, block_end_pfn, - &freelist, true); + isolated = isolate_freepages_block(cc, &isolate_start_pfn, + block_end_pfn, &freelist, true); /* * In strict mode, isolate_freepages_block() returns 0 if @@ -769,6 +775,7 @@ static void isolate_freepages(struct compact_control *cc) struct zone *zone = cc->zone; struct page *page; unsigned long block_start_pfn; /* start of current pageblock */ + 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 */ int nr_freepages = cc->nr_freepages; @@ -777,14 +784,15 @@ static void isolate_freepages(struct compact_control *cc) /* * Initialise the free scanner. The starting point is where we last * successfully isolated from, zone-cached value, or the end of the - * zone when isolating for the first time. We need this aligned to - * the pageblock boundary, because we do + * zone when isolating for the first time. For looping we also need + * this pfn aligned down to the pageblock boundary, because we do * block_start_pfn -= pageblock_nr_pages in the for loop. * For ending point, take care when isolating in last pageblock of a * a zone which ends in the middle of a pageblock. * The low boundary is the end of the pageblock the migration scanner * is using. */ + isolate_start_pfn = cc->free_pfn; block_start_pfn = cc->free_pfn & ~(pageblock_nr_pages-1); block_end_pfn = min(block_start_pfn + pageblock_nr_pages, zone_end_pfn(zone)); @@ -797,7 +805,8 @@ static void isolate_freepages(struct compact_control *cc) */ for (; block_start_pfn >= low_pfn && cc->nr_migratepages > nr_freepages; block_end_pfn = block_start_pfn, - block_start_pfn -= pageblock_nr_pages) { + block_start_pfn -= pageblock_nr_pages, + isolate_start_pfn = block_start_pfn) { unsigned long isolated; /* @@ -822,13 +831,25 @@ static void isolate_freepages(struct compact_control *cc) if (!isolation_suitable(cc, page)) continue; - /* Found a block suitable for isolating free pages from */ - cc->free_pfn = block_start_pfn; - isolated = isolate_freepages_block(cc, block_start_pfn, + /* Found a block suitable for isolating free pages from. */ + isolated = isolate_freepages_block(cc, &isolate_start_pfn, block_end_pfn, freelist, false); nr_freepages += isolated; /* + * Remember where the free scanner should restart next time, + * which is where isolate_freepages_block() left off. + * But if it scanned the whole pageblock, isolate_start_pfn + * now points at block_end_pfn, which is the start of the next + * pageblock. + * In that case we will however want to restart at the start + * of the previous pageblock. + */ + cc->free_pfn = (isolate_start_pfn < block_end_pfn) ? + isolate_start_pfn : + block_start_pfn - pageblock_nr_pages; + + /* * Set a flag that we successfully isolated in this pageblock. * In the next loop iteration, zone->compact_cached_free_pfn * will not be updated and thus it will effectively contain the |