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-rw-r--r--mm/vmscan.c119
1 files changed, 69 insertions, 50 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 4dbac2008..8286938c7 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -154,11 +154,42 @@ static bool global_reclaim(struct scan_control *sc)
{
return !sc->target_mem_cgroup;
}
+
+/**
+ * sane_reclaim - is the usual dirty throttling mechanism operational?
+ * @sc: scan_control in question
+ *
+ * The normal page dirty throttling mechanism in balance_dirty_pages() is
+ * completely broken with the legacy memcg and direct stalling in
+ * shrink_page_list() is used for throttling instead, which lacks all the
+ * niceties such as fairness, adaptive pausing, bandwidth proportional
+ * allocation and configurability.
+ *
+ * This function tests whether the vmscan currently in progress can assume
+ * that the normal dirty throttling mechanism is operational.
+ */
+static bool sane_reclaim(struct scan_control *sc)
+{
+ struct mem_cgroup *memcg = sc->target_mem_cgroup;
+
+ if (!memcg)
+ return true;
+#ifdef CONFIG_CGROUP_WRITEBACK
+ if (cgroup_on_dfl(mem_cgroup_css(memcg)->cgroup))
+ return true;
+#endif
+ return false;
+}
#else
static bool global_reclaim(struct scan_control *sc)
{
return true;
}
+
+static bool sane_reclaim(struct scan_control *sc)
+{
+ return true;
+}
#endif
static unsigned long zone_reclaimable_pages(struct zone *zone)
@@ -452,14 +483,13 @@ static inline int is_page_cache_freeable(struct page *page)
return page_count(page) - page_has_private(page) == 2;
}
-static int may_write_to_queue(struct backing_dev_info *bdi,
- struct scan_control *sc)
+static int may_write_to_inode(struct inode *inode, struct scan_control *sc)
{
if (current->flags & PF_SWAPWRITE)
return 1;
- if (!bdi_write_congested(bdi))
+ if (!inode_write_congested(inode))
return 1;
- if (bdi == current->backing_dev_info)
+ if (inode_to_bdi(inode) == current->backing_dev_info)
return 1;
return 0;
}
@@ -538,7 +568,7 @@ static pageout_t pageout(struct page *page, struct address_space *mapping,
}
if (mapping->a_ops->writepage == NULL)
return PAGE_ACTIVATE;
- if (!may_write_to_queue(inode_to_bdi(mapping->host), sc))
+ if (!may_write_to_inode(mapping->host, sc))
return PAGE_KEEP;
if (clear_page_dirty_for_io(page)) {
@@ -579,10 +609,14 @@ static pageout_t pageout(struct page *page, struct address_space *mapping,
static int __remove_mapping(struct address_space *mapping, struct page *page,
bool reclaimed)
{
+ unsigned long flags;
+ struct mem_cgroup *memcg;
+
BUG_ON(!PageLocked(page));
BUG_ON(mapping != page_mapping(page));
- spin_lock_irq(&mapping->tree_lock);
+ memcg = mem_cgroup_begin_page_stat(page);
+ spin_lock_irqsave(&mapping->tree_lock, flags);
/*
* The non racy check for a busy page.
*
@@ -620,7 +654,8 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
swp_entry_t swap = { .val = page_private(page) };
mem_cgroup_swapout(page, swap);
__delete_from_swap_cache(page);
- spin_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irqrestore(&mapping->tree_lock, flags);
+ mem_cgroup_end_page_stat(memcg);
swapcache_free(swap);
} else {
void (*freepage)(struct page *);
@@ -640,8 +675,9 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
if (reclaimed && page_is_file_cache(page) &&
!mapping_exiting(mapping))
shadow = workingset_eviction(mapping, page);
- __delete_from_page_cache(page, shadow);
- spin_unlock_irq(&mapping->tree_lock);
+ __delete_from_page_cache(page, shadow, memcg);
+ spin_unlock_irqrestore(&mapping->tree_lock, flags);
+ mem_cgroup_end_page_stat(memcg);
if (freepage != NULL)
freepage(page);
@@ -650,7 +686,8 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
return 1;
cannot_free:
- spin_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irqrestore(&mapping->tree_lock, flags);
+ mem_cgroup_end_page_stat(memcg);
return 0;
}
@@ -917,7 +954,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
*/
mapping = page_mapping(page);
if (((dirty || writeback) && mapping &&
- bdi_write_congested(inode_to_bdi(mapping->host))) ||
+ inode_write_congested(mapping->host)) ||
(writeback && PageReclaim(page)))
nr_congested++;
@@ -935,11 +972,11 @@ static unsigned long shrink_page_list(struct list_head *page_list,
* note that the LRU is being scanned too quickly and the
* caller can stall after page list has been processed.
*
- * 2) Global reclaim encounters a page, memcg encounters a
- * page that is not marked for immediate reclaim or
- * the caller does not have __GFP_FS (or __GFP_IO if it's
- * simply going to swap, not to fs). In this case mark
- * the page for immediate reclaim and continue scanning.
+ * 2) Global or new memcg reclaim encounters a page that is
+ * not marked for immediate reclaim, or the caller does not
+ * have __GFP_FS (or __GFP_IO if it's simply going to swap,
+ * not to fs). In this case mark the page for immediate
+ * reclaim and continue scanning.
*
* Require may_enter_fs because we would wait on fs, which
* may not have submitted IO yet. And the loop driver might
@@ -948,7 +985,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
* __GFP_IO|__GFP_FS for this reason); but more thought
* would probably show more reasons.
*
- * 3) memcg encounters a page that is not already marked
+ * 3) Legacy memcg encounters a page that is not already marked
* PageReclaim. memcg does not have any dirty pages
* throttling so we could easily OOM just because too many
* pages are in writeback and there is nothing else to
@@ -963,7 +1000,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
goto keep_locked;
/* Case 2 above */
- } else if (global_reclaim(sc) ||
+ } else if (sane_reclaim(sc) ||
!PageReclaim(page) || !may_enter_fs) {
/*
* This is slightly racy - end_page_writeback()
@@ -1409,10 +1446,10 @@ static int too_many_isolated(struct zone *zone, int file,
{
unsigned long inactive, isolated;
- if (current_is_kswapd() || sc->hibernation_mode)
+ if (current_is_kswapd())
return 0;
- if (!global_reclaim(sc))
+ if (!sane_reclaim(sc))
return 0;
if (file) {
@@ -1604,10 +1641,10 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
set_bit(ZONE_WRITEBACK, &zone->flags);
/*
- * memcg will stall in page writeback so only consider forcibly
- * stalling for global reclaim
+ * Legacy memcg will stall in page writeback so avoid forcibly
+ * stalling here.
*/
- if (global_reclaim(sc)) {
+ if (sane_reclaim(sc)) {
/*
* Tag a zone as congested if all the dirty pages scanned were
* backed by a congested BDI and wait_iff_congested will stall.
@@ -2258,9 +2295,6 @@ static inline bool should_continue_reclaim(struct zone *zone,
unsigned long pages_for_compaction;
unsigned long inactive_lru_pages;
- if (nr_reclaimed && nr_scanned && sc->nr_to_reclaim >= sc->nr_reclaimed)
- return true;
-
/* If not in reclaim/compaction mode, stop */
if (!in_reclaim_compaction(sc))
return false;
@@ -2571,12 +2605,6 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
unsigned long total_scanned = 0;
unsigned long writeback_threshold;
bool zones_reclaimable;
-
-#ifdef CONFIG_FREEZER
- if (unlikely(pm_freezing && !sc->hibernation_mode))
- return 0;
-#endif
-
retry:
delayacct_freepages_start();
@@ -2651,7 +2679,8 @@ static bool pfmemalloc_watermark_ok(pg_data_t *pgdat)
for (i = 0; i <= ZONE_NORMAL; i++) {
zone = &pgdat->node_zones[i];
- if (!populated_zone(zone))
+ if (!populated_zone(zone) ||
+ zone_reclaimable_pages(zone) == 0)
continue;
pfmemalloc_reserve += min_wmark_pages(zone);
@@ -3459,11 +3488,6 @@ void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx)
if (!populated_zone(zone))
return;
-#ifdef CONFIG_FREEZER
- if (pm_freezing)
- return;
-#endif
-
if (!cpuset_zone_allowed(zone, GFP_KERNEL | __GFP_HARDWALL))
return;
pgdat = zone->zone_pgdat;
@@ -3489,7 +3513,7 @@ void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx)
* LRU order by reclaiming preferentially
* inactive > active > active referenced > active mapped
*/
-unsigned long shrink_memory_mask(unsigned long nr_to_reclaim, gfp_t mask)
+unsigned long shrink_all_memory(unsigned long nr_to_reclaim)
{
struct reclaim_state reclaim_state;
struct scan_control sc = {
@@ -3518,11 +3542,6 @@ unsigned long shrink_memory_mask(unsigned long nr_to_reclaim, gfp_t mask)
return nr_reclaimed;
}
-
-unsigned long shrink_all_memory(unsigned long nr_to_reclaim)
-{
- return shrink_memory_mask(nr_to_reclaim, GFP_HIGHUSER_MOVABLE);
-}
#endif /* CONFIG_HIBERNATION */
/* It's optimal to keep kswapds on the same CPUs as their memory, but
@@ -3611,7 +3630,7 @@ int zone_reclaim_mode __read_mostly;
#define RECLAIM_OFF 0
#define RECLAIM_ZONE (1<<0) /* Run shrink_inactive_list on the zone */
#define RECLAIM_WRITE (1<<1) /* Writeout pages during reclaim */
-#define RECLAIM_SWAP (1<<2) /* Swap pages out during reclaim */
+#define RECLAIM_UNMAP (1<<2) /* Unmap pages during reclaim */
/*
* Priority for ZONE_RECLAIM. This determines the fraction of pages
@@ -3653,12 +3672,12 @@ static long zone_pagecache_reclaimable(struct zone *zone)
long delta = 0;
/*
- * If RECLAIM_SWAP is set, then all file pages are considered
+ * If RECLAIM_UNMAP is set, then all file pages are considered
* potentially reclaimable. Otherwise, we have to worry about
* pages like swapcache and zone_unmapped_file_pages() provides
* a better estimate
*/
- if (zone_reclaim_mode & RECLAIM_SWAP)
+ if (zone_reclaim_mode & RECLAIM_UNMAP)
nr_pagecache_reclaimable = zone_page_state(zone, NR_FILE_PAGES);
else
nr_pagecache_reclaimable = zone_unmapped_file_pages(zone);
@@ -3689,15 +3708,15 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
.order = order,
.priority = ZONE_RECLAIM_PRIORITY,
.may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE),
- .may_unmap = !!(zone_reclaim_mode & RECLAIM_SWAP),
+ .may_unmap = !!(zone_reclaim_mode & RECLAIM_UNMAP),
.may_swap = 1,
};
cond_resched();
/*
- * We need to be able to allocate from the reserves for RECLAIM_SWAP
+ * We need to be able to allocate from the reserves for RECLAIM_UNMAP
* and we also need to be able to write out pages for RECLAIM_WRITE
- * and RECLAIM_SWAP.
+ * and RECLAIM_UNMAP.
*/
p->flags |= PF_MEMALLOC | PF_SWAPWRITE;
lockdep_set_current_reclaim_state(gfp_mask);