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authorLinus Torvalds <torvalds@linux-foundation.org>2016-12-13 07:50:02 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-13 07:50:02 +0300
commite34bac726d27056081d0250c0e173e4b155aa340 (patch)
tree85607d0b3b185380fb3267866020c6a4372b9298 /mm/page_alloc.c
parentfe6bce8d30a86c693bf7cfbf4759cbafd121289f (diff)
parent39a0e975c37dee93fa1b8ea5f7eacd1c4c8a586e (diff)
downloadlinux-e34bac726d27056081d0250c0e173e4b155aa340.tar.xz
Merge branch 'akpm' (patches from Andrew)
Merge updates from Andrew Morton: - various misc bits - most of MM (quite a lot of MM material is awaiting the merge of linux-next dependencies) - kasan - printk updates - procfs updates - MAINTAINERS - /lib updates - checkpatch updates * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (123 commits) init: reduce rootwait polling interval time to 5ms binfmt_elf: use vmalloc() for allocation of vma_filesz checkpatch: don't emit unified-diff error for rename-only patches checkpatch: don't check c99 types like uint8_t under tools checkpatch: avoid multiple line dereferences checkpatch: don't check .pl files, improve absolute path commit log test scripts/checkpatch.pl: fix spelling checkpatch: don't try to get maintained status when --no-tree is given lib/ida: document locking requirements a bit better lib/rbtree.c: fix typo in comment of ____rb_erase_color lib/Kconfig.debug: make CONFIG_STRICT_DEVMEM depend on CONFIG_DEVMEM MAINTAINERS: add drm and drm/i915 irc channels MAINTAINERS: add "C:" for URI for chat where developers hang out MAINTAINERS: add drm and drm/i915 bug filing info MAINTAINERS: add "B:" for URI where to file bugs get_maintainer: look for arbitrary letter prefixes in sections printk: add Kconfig option to set default console loglevel printk/sound: handle more message headers printk/btrfs: handle more message headers printk/kdb: handle more message headers ...
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c75
1 files changed, 56 insertions, 19 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3dcc54da5637..f64e7bcb43b7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2058,8 +2058,12 @@ out_unlock:
* potentially hurts the reliability of high-order allocations when under
* intense memory pressure but failed atomic allocations should be easier
* to recover from than an OOM.
+ *
+ * If @force is true, try to unreserve a pageblock even though highatomic
+ * pageblock is exhausted.
*/
-static void unreserve_highatomic_pageblock(const struct alloc_context *ac)
+static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
+ bool force)
{
struct zonelist *zonelist = ac->zonelist;
unsigned long flags;
@@ -2067,11 +2071,16 @@ static void unreserve_highatomic_pageblock(const struct alloc_context *ac)
struct zone *zone;
struct page *page;
int order;
+ bool ret;
for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->high_zoneidx,
ac->nodemask) {
- /* Preserve at least one pageblock */
- if (zone->nr_reserved_highatomic <= pageblock_nr_pages)
+ /*
+ * Preserve at least one pageblock unless memory pressure
+ * is really high.
+ */
+ if (!force && zone->nr_reserved_highatomic <=
+ pageblock_nr_pages)
continue;
spin_lock_irqsave(&zone->lock, flags);
@@ -2085,13 +2094,25 @@ static void unreserve_highatomic_pageblock(const struct alloc_context *ac)
continue;
/*
- * It should never happen but changes to locking could
- * inadvertently allow a per-cpu drain to add pages
- * to MIGRATE_HIGHATOMIC while unreserving so be safe
- * and watch for underflows.
+ * In page freeing path, migratetype change is racy so
+ * we can counter several free pages in a pageblock
+ * in this loop althoug we changed the pageblock type
+ * from highatomic to ac->migratetype. So we should
+ * adjust the count once.
*/
- zone->nr_reserved_highatomic -= min(pageblock_nr_pages,
- zone->nr_reserved_highatomic);
+ if (get_pageblock_migratetype(page) ==
+ MIGRATE_HIGHATOMIC) {
+ /*
+ * It should never happen but changes to
+ * locking could inadvertently allow a per-cpu
+ * drain to add pages to MIGRATE_HIGHATOMIC
+ * while unreserving so be safe and watch for
+ * underflows.
+ */
+ zone->nr_reserved_highatomic -= min(
+ pageblock_nr_pages,
+ zone->nr_reserved_highatomic);
+ }
/*
* Convert to ac->migratetype and avoid the normal
@@ -2103,12 +2124,16 @@ static void unreserve_highatomic_pageblock(const struct alloc_context *ac)
* may increase.
*/
set_pageblock_migratetype(page, ac->migratetype);
- move_freepages_block(zone, page, ac->migratetype);
- spin_unlock_irqrestore(&zone->lock, flags);
- return;
+ ret = move_freepages_block(zone, page, ac->migratetype);
+ if (ret) {
+ spin_unlock_irqrestore(&zone->lock, flags);
+ return ret;
+ }
}
spin_unlock_irqrestore(&zone->lock, flags);
}
+
+ return false;
}
/* Remove an element from the buddy allocator from the fallback list */
@@ -2133,7 +2158,8 @@ __rmqueue_fallback(struct zone *zone, unsigned int order, int start_migratetype)
page = list_first_entry(&area->free_list[fallback_mt],
struct page, lru);
- if (can_steal)
+ if (can_steal &&
+ get_pageblock_migratetype(page) != MIGRATE_HIGHATOMIC)
steal_suitable_fallback(zone, page, start_migratetype);
/* Remove the page from the freelists */
@@ -2192,7 +2218,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
unsigned long count, struct list_head *list,
int migratetype, bool cold)
{
- int i;
+ int i, alloced = 0;
spin_lock(&zone->lock);
for (i = 0; i < count; ++i) {
@@ -2217,13 +2243,21 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
else
list_add_tail(&page->lru, list);
list = &page->lru;
+ alloced++;
if (is_migrate_cma(get_pcppage_migratetype(page)))
__mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
-(1 << order));
}
+
+ /*
+ * i pages were removed from the buddy list even if some leak due
+ * to check_pcp_refill failing so adjust NR_FREE_PAGES based
+ * on i. Do not confuse with 'alloced' which is the number of
+ * pages added to the pcp list.
+ */
__mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
spin_unlock(&zone->lock);
- return i;
+ return alloced;
}
#ifdef CONFIG_NUMA
@@ -2534,7 +2568,8 @@ int __isolate_free_page(struct page *page, unsigned int order)
struct page *endpage = page + (1 << order) - 1;
for (; page < endpage; page += pageblock_nr_pages) {
int mt = get_pageblock_migratetype(page);
- if (!is_migrate_isolate(mt) && !is_migrate_cma(mt))
+ if (!is_migrate_isolate(mt) && !is_migrate_cma(mt)
+ && mt != MIGRATE_HIGHATOMIC)
set_pageblock_migratetype(page,
MIGRATE_MOVABLE);
}
@@ -3305,7 +3340,7 @@ retry:
* Shrink them them and try again
*/
if (!page && !drained) {
- unreserve_highatomic_pageblock(ac);
+ unreserve_highatomic_pageblock(ac, false);
drain_all_pages(NULL);
drained = true;
goto retry;
@@ -3422,8 +3457,10 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order,
* Make sure we converge to OOM if we cannot make any progress
* several times in the row.
*/
- if (*no_progress_loops > MAX_RECLAIM_RETRIES)
- return false;
+ if (*no_progress_loops > MAX_RECLAIM_RETRIES) {
+ /* Before OOM, exhaust highatomic_reserve */
+ return unreserve_highatomic_pageblock(ac, true);
+ }
/*
* Keep reclaiming pages while there is a chance this will lead