The patch titled
Subject: mm: remove reclaim and compaction retry approximations
has been added to the -mm tree. Its filename is
mm-remove-reclaim-and-compaction-retry-approximations.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-remove-reclaim-and-compaction-retry-approximations.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-remove-reclaim-and-compaction-retry-approximations.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Subject: 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@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mmzone.h | 1
include/linux/swap.h | 1
mm/compaction.c | 20 ---------------
mm/migrate.c | 2 +
mm/page-writeback.c | 5 +++
mm/page_alloc.c | 49 +++++++--------------------------------
mm/vmscan.c | 18 ++++++++++++++
mm/vmstat.c | 1
8 files changed, 39 insertions(+), 58 deletions(-)
diff -puN include/linux/mmzone.h~mm-remove-reclaim-and-compaction-retry-approximations include/linux/mmzone.h
--- a/include/linux/mmzone.h~mm-remove-reclaim-and-compaction-retry-approximations
+++ a/include/linux/mmzone.h
@@ -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,
diff -puN include/linux/swap.h~mm-remove-reclaim-and-compaction-retry-approximations include/linux/swap.h
--- a/include/linux/swap.h~mm-remove-reclaim-and-compaction-retry-approximations
+++ a/include/linux/swap.h
@@ -307,6 +307,7 @@ extern void lru_cache_add_active_or_unev
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);
diff -puN mm/compaction.c~mm-remove-reclaim-and-compaction-retry-approximations mm/compaction.c
--- a/mm/compaction.c~mm-remove-reclaim-and-compaction-retry-approximations
+++ a/mm/compaction.c
@@ -1438,11 +1438,6 @@ bool compaction_zonelist_suitable(struct
{
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
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 &&
diff -puN mm/migrate.c~mm-remove-reclaim-and-compaction-retry-approximations mm/migrate.c
--- a/mm/migrate.c~mm-remove-reclaim-and-compaction-retry-approximations
+++ a/mm/migrate.c
@@ -513,7 +513,9 @@ int migrate_page_move_mapping(struct add
}
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();
diff -puN mm/page-writeback.c~mm-remove-reclaim-and-compaction-retry-approximations mm/page-writeback.c
--- a/mm/page-writeback.c~mm-remove-reclaim-and-compaction-retry-approximations
+++ a/mm/page-writeback.c
@@ -2462,6 +2462,7 @@ void account_page_dirtied(struct page *p
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 *p
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
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 pag
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 pag
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;
diff -puN mm/page_alloc.c~mm-remove-reclaim-and-compaction-retry-approximations mm/page_alloc.c
--- a/mm/page_alloc.c~mm-remove-reclaim-and-compaction-retry-approximations
+++ a/mm/page_alloc.c
@@ -3402,7 +3402,6 @@ should_reclaim_retry(gfp_t gfp_mask, uns
{
struct zone *zone;
struct zoneref *z;
- pg_data_t *current_pgdat = NULL;
/*
* Make sure we converge to OOM if we cannot make any progress
@@ -3412,15 +3411,6 @@ should_reclaim_retry(gfp_t gfp_mask, uns
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 request even
* if all reclaimable pages are considered then we are screwed and have
@@ -3430,38 +3420,18 @@ should_reclaim_retry(gfp_t gfp_mask, uns
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 = ¤t_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 = ¤t_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, uns
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)),
diff -puN mm/vmscan.c~mm-remove-reclaim-and-compaction-retry-approximations mm/vmscan.c
--- a/mm/vmscan.c~mm-remove-reclaim-and-compaction-retry-approximations
+++ a/mm/vmscan.c
@@ -194,6 +194,24 @@ static bool sane_reclaim(struct scan_con
}
#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;
diff -puN mm/vmstat.c~mm-remove-reclaim-and-compaction-retry-approximations mm/vmstat.c
--- a/mm/vmstat.c~mm-remove-reclaim-and-compaction-retry-approximations
+++ a/mm/vmstat.c
@@ -926,6 +926,7 @@ const char * const vmstat_text[] = {
"nr_inactive_file",
"nr_active_file",
"nr_unevictable",
+ "nr_zone_write_pending",
"nr_mlock",
"nr_slab_reclaimable",
"nr_slab_unreclaimable",
_
Patches currently in -mm which might be from mgorman@xxxxxxxxxxxxxxxxxxx are
mm-meminit-remove-early_page_nid_uninitialised.patch
mm-vmstat-add-infrastructure-for-per-node-vmstats.patch
mm-vmscan-move-lru_lock-to-the-node.patch
mm-vmscan-move-lru-lists-to-node.patch
mm-mmzone-clarify-the-usage-of-zone-padding.patch
mm-vmscan-begin-reclaiming-pages-on-a-per-node-basis.patch
mm-vmscan-have-kswapd-only-scan-based-on-the-highest-requested-zone.patch
mm-vmscan-make-kswapd-reclaim-in-terms-of-nodes.patch
mm-vmscan-remove-balance-gap.patch
mm-vmscan-simplify-the-logic-deciding-whether-kswapd-sleeps.patch
mm-vmscan-by-default-have-direct-reclaim-only-shrink-once-per-node.patch
mm-vmscan-remove-duplicate-logic-clearing-node-congestion-and-dirty-state.patch
mm-vmscan-do-not-reclaim-from-kswapd-if-there-is-any-eligible-zone.patch
mm-vmscan-make-shrink_node-decisions-more-node-centric.patch
mm-vmscan-make-shrink_node-decisions-more-node-centric-fix.patch
mm-memcg-move-memcg-limit-enforcement-from-zones-to-nodes.patch
mm-workingset-make-working-set-detection-node-aware.patch
mm-page_alloc-consider-dirtyable-memory-in-terms-of-nodes.patch
mm-move-page-mapped-accounting-to-the-node.patch
mm-rename-nr_anon_pages-to-nr_anon_mapped.patch
mm-move-most-file-based-accounting-to-the-node.patch
mm-move-most-file-based-accounting-to-the-node-fix.patch
mm-move-vmscan-writes-and-file-write-accounting-to-the-node.patch
mm-vmscan-only-wakeup-kswapd-once-per-node-for-the-requested-classzone.patch
mm-page_alloc-wake-kswapd-based-on-the-highest-eligible-zone.patch
mm-convert-zone_reclaim-to-node_reclaim.patch
mm-vmscan-avoid-passing-in-classzone_idx-unnecessarily-to-shrink_node.patch
mm-vmscan-avoid-passing-in-classzone_idx-unnecessarily-to-compaction_ready.patch
mm-vmscan-avoid-passing-in-classzone_idx-unnecessarily-to-compaction_ready-fix.patch
mm-vmscan-avoid-passing-in-remaining-unnecessarily-to-prepare_kswapd_sleep.patch
mm-vmscan-have-kswapd-reclaim-from-all-zones-if-reclaiming-and-buffer_heads_over_limit.patch
mm-vmscan-have-kswapd-reclaim-from-all-zones-if-reclaiming-and-buffer_heads_over_limit-fix.patch
mm-vmscan-add-classzone-information-to-tracepoints.patch
mm-page_alloc-remove-fair-zone-allocation-policy.patch
mm-page_alloc-cache-the-last-node-whose-dirty-limit-is-reached.patch
mm-vmstat-replace-__count_zone_vm_events-with-a-zone-id-equivalent.patch
mm-vmstat-account-per-zone-stalls-and-pages-skipped-during-reclaim.patch
mm-vmstat-account-per-zone-stalls-and-pages-skipped-during-reclaim-fix.patch
mm-vmstat-print-node-based-stats-in-zoneinfo-file.patch
mm-vmstat-remove-zone-and-node-double-accounting-by-approximating-retries.patch
mm-vmstat-remove-zone-and-node-double-accounting-by-approximating-retries-fix.patch
mm-pagevec-release-reacquire-lru_lock-on-pgdat-change.patch
mm-vmscan-update-all-zone-lru-sizes-before-updating-memcg.patch
mm-vmscan-remove-redundant-check-in-shrink_zones.patch
mm-vmscan-release-reacquire-lru_lock-on-pgdat-change.patch
mm-vmscan-release-reacquire-lru_lock-on-pgdat-change-fix.patch
mm-vmscan-remove-highmem_file_pages.patch
mm-remove-reclaim-and-compaction-retry-approximations.patch
mm-vmscan-account-for-skipped-pages-as-a-partial-scan.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
