Commit 5a1c84b4 authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds

mm: remove reclaim and compaction retry approximations

If per-zone LRU accounting is available then there is no point
approximating whether reclaim and compaction should retry based on pgdat
statistics.  This is effectively a revert of "mm, vmstat: remove zone
and node double accounting by approximating retries" with the difference
that inactive/active stats are still available.  This preserves the
history of why the approximation was retried and why it had to be
reverted to handle OOM kills on 32-bit systems.

Link: http://lkml.kernel.org/r/1469110261-7365-4-git-send-email-mgorman@techsingularity.netSigned-off-by: default avatarMel Gorman <mgorman@techsingularity.net>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarMinchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent bb4cc2be
......@@ -116,6 +116,7 @@ enum zone_stat_item {
NR_ZONE_INACTIVE_FILE,
NR_ZONE_ACTIVE_FILE,
NR_ZONE_UNEVICTABLE,
NR_ZONE_WRITE_PENDING, /* Count of dirty, writeback and unstable pages */
NR_MLOCK, /* mlock()ed pages found and moved off LRU */
NR_SLAB_RECLAIMABLE,
NR_SLAB_UNRECLAIMABLE,
......
......@@ -307,6 +307,7 @@ extern void lru_cache_add_active_or_unevictable(struct page *page,
struct vm_area_struct *vma);
/* linux/mm/vmscan.c */
extern unsigned long zone_reclaimable_pages(struct zone *zone);
extern unsigned long pgdat_reclaimable_pages(struct pglist_data *pgdat);
extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
gfp_t gfp_mask, nodemask_t *mask);
......
......@@ -1438,11 +1438,6 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
{
struct zone *zone;
struct zoneref *z;
pg_data_t *last_pgdat = NULL;
/* Do not retry compaction for zone-constrained allocations */
if (ac->high_zoneidx < ZONE_NORMAL)
return false;
/*
* Make sure at least one zone would pass __compaction_suitable if we continue
......@@ -1453,27 +1448,14 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
unsigned long available;
enum compact_result compact_result;
if (last_pgdat == zone->zone_pgdat)
continue;
/*
* This over-estimates the number of pages available for
* reclaim/compaction but walking the LRU would take too
* long. The consequences are that compaction may retry
* longer than it should for a zone-constrained allocation
* request.
*/
last_pgdat = zone->zone_pgdat;
available = pgdat_reclaimable_pages(zone->zone_pgdat) / order;
/*
* Do not consider all the reclaimable memory because we do not
* want to trash just for a single high order allocation which
* is even not guaranteed to appear even if __compaction_suitable
* is happy about the watermark check.
*/
available = zone_reclaimable_pages(zone) / order;
available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
available = min(zone->managed_pages, available);
compact_result = __compaction_suitable(zone, order, alloc_flags,
ac_classzone_idx(ac), available);
if (compact_result != COMPACT_SKIPPED &&
......
......@@ -513,7 +513,9 @@ int migrate_page_move_mapping(struct address_space *mapping,
}
if (dirty && mapping_cap_account_dirty(mapping)) {
__dec_node_state(oldzone->zone_pgdat, NR_FILE_DIRTY);
__dec_zone_state(oldzone, NR_ZONE_WRITE_PENDING);
__inc_node_state(newzone->zone_pgdat, NR_FILE_DIRTY);
__inc_zone_state(newzone, NR_ZONE_WRITE_PENDING);
}
}
local_irq_enable();
......
......@@ -2462,6 +2462,7 @@ void account_page_dirtied(struct page *page, struct address_space *mapping)
mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_DIRTY);
__inc_node_page_state(page, NR_FILE_DIRTY);
__inc_zone_page_state(page, NR_ZONE_WRITE_PENDING);
__inc_node_page_state(page, NR_DIRTIED);
__inc_wb_stat(wb, WB_RECLAIMABLE);
__inc_wb_stat(wb, WB_DIRTIED);
......@@ -2483,6 +2484,7 @@ void account_page_cleaned(struct page *page, struct address_space *mapping,
if (mapping_cap_account_dirty(mapping)) {
mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_DIRTY);
dec_node_page_state(page, NR_FILE_DIRTY);
dec_zone_page_state(page, NR_ZONE_WRITE_PENDING);
dec_wb_stat(wb, WB_RECLAIMABLE);
task_io_account_cancelled_write(PAGE_SIZE);
}
......@@ -2739,6 +2741,7 @@ int clear_page_dirty_for_io(struct page *page)
if (TestClearPageDirty(page)) {
mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_DIRTY);
dec_node_page_state(page, NR_FILE_DIRTY);
dec_zone_page_state(page, NR_ZONE_WRITE_PENDING);
dec_wb_stat(wb, WB_RECLAIMABLE);
ret = 1;
}
......@@ -2785,6 +2788,7 @@ int test_clear_page_writeback(struct page *page)
if (ret) {
mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_WRITEBACK);
dec_node_page_state(page, NR_WRITEBACK);
dec_zone_page_state(page, NR_ZONE_WRITE_PENDING);
inc_node_page_state(page, NR_WRITTEN);
}
unlock_page_memcg(page);
......@@ -2839,6 +2843,7 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
if (!ret) {
mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_WRITEBACK);
inc_node_page_state(page, NR_WRITEBACK);
inc_zone_page_state(page, NR_ZONE_WRITE_PENDING);
}
unlock_page_memcg(page);
return ret;
......
......@@ -3402,7 +3402,6 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order,
{
struct zone *zone;
struct zoneref *z;
pg_data_t *current_pgdat = NULL;
/*
* Make sure we converge to OOM if we cannot make any progress
......@@ -3411,15 +3410,6 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order,
if (no_progress_loops > MAX_RECLAIM_RETRIES)
return false;
/*
* Blindly retry lowmem allocation requests that are often ignored by
* the OOM killer up to MAX_RECLAIM_RETRIES as we not have a reliable
* and fast means of calculating reclaimable, dirty and writeback pages
* in eligible zones.
*/
if (ac->high_zoneidx < ZONE_NORMAL)
goto out;
/*
* Keep reclaiming pages while there is a chance this will lead
* somewhere. If none of the target zones can satisfy our allocation
......@@ -3430,38 +3420,18 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order,
ac->nodemask) {
unsigned long available;
unsigned long reclaimable;
int zid;
if (current_pgdat == zone->zone_pgdat)
continue;
current_pgdat = zone->zone_pgdat;
available = reclaimable = pgdat_reclaimable_pages(current_pgdat);
available = reclaimable = zone_reclaimable_pages(zone);
available -= DIV_ROUND_UP(no_progress_loops * available,
MAX_RECLAIM_RETRIES);
/* Account for all free pages on eligible zones */
for (zid = 0; zid <= zone_idx(zone); zid++) {
struct zone *acct_zone = &current_pgdat->node_zones[zid];
available += zone_page_state_snapshot(acct_zone, NR_FREE_PAGES);
}
available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
/*
* Would the allocation succeed if we reclaimed the whole
* available? This is approximate because there is no
* accurate count of reclaimable pages per zone.
* available?
*/
for (zid = 0; zid <= zone_idx(zone); zid++) {
struct zone *check_zone = &current_pgdat->node_zones[zid];
unsigned long estimate;
estimate = min(check_zone->managed_pages, available);
if (!__zone_watermark_ok(check_zone, order,
min_wmark_pages(check_zone), ac_classzone_idx(ac),
alloc_flags, estimate))
continue;
if (__zone_watermark_ok(zone, order, min_wmark_pages(zone),
ac_classzone_idx(ac), alloc_flags, available)) {
/*
* If we didn't make any progress and have a lot of
* dirty + writeback pages then we should wait for
......@@ -3471,16 +3441,15 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order,
if (!did_some_progress) {
unsigned long write_pending;
write_pending =
node_page_state(current_pgdat, NR_WRITEBACK) +
node_page_state(current_pgdat, NR_FILE_DIRTY);
write_pending = zone_page_state_snapshot(zone,
NR_ZONE_WRITE_PENDING);
if (2 * write_pending > reclaimable) {
congestion_wait(BLK_RW_ASYNC, HZ/10);
return true;
}
}
out:
/*
* Memory allocation/reclaim might be called from a WQ
* context and the current implementation of the WQ
......@@ -4361,6 +4330,7 @@ void show_free_areas(unsigned int filter)
" active_file:%lukB"
" inactive_file:%lukB"
" unevictable:%lukB"
" writepending:%lukB"
" present:%lukB"
" managed:%lukB"
" mlocked:%lukB"
......@@ -4383,6 +4353,7 @@ void show_free_areas(unsigned int filter)
K(zone_page_state(zone, NR_ZONE_ACTIVE_FILE)),
K(zone_page_state(zone, NR_ZONE_INACTIVE_FILE)),
K(zone_page_state(zone, NR_ZONE_UNEVICTABLE)),
K(zone_page_state(zone, NR_ZONE_WRITE_PENDING)),
K(zone->present_pages),
K(zone->managed_pages),
K(zone_page_state(zone, NR_MLOCK)),
......
......@@ -194,6 +194,24 @@ static bool sane_reclaim(struct scan_control *sc)
}
#endif
/*
* This misses isolated pages which are not accounted for to save counters.
* As the data only determines if reclaim or compaction continues, it is
* not expected that isolated pages will be a dominating factor.
*/
unsigned long zone_reclaimable_pages(struct zone *zone)
{
unsigned long nr;
nr = zone_page_state_snapshot(zone, NR_ZONE_INACTIVE_FILE) +
zone_page_state_snapshot(zone, NR_ZONE_ACTIVE_FILE);
if (get_nr_swap_pages() > 0)
nr += zone_page_state_snapshot(zone, NR_ZONE_INACTIVE_ANON) +
zone_page_state_snapshot(zone, NR_ZONE_ACTIVE_ANON);
return nr;
}
unsigned long pgdat_reclaimable_pages(struct pglist_data *pgdat)
{
unsigned long nr;
......
......@@ -926,6 +926,7 @@ const char * const vmstat_text[] = {
"nr_zone_inactive_file",
"nr_zone_active_file",
"nr_zone_unevictable",
"nr_zone_write_pending",
"nr_mlock",
"nr_slab_reclaimable",
"nr_slab_unreclaimable",
......
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