Commit 258401a6 authored by Zlatko Calusic's avatar Zlatko Calusic Committed by Linus Torvalds

mm: don't wait on congested zones in balance_pgdat()

From: Zlatko Calusic <zlatko.calusic@iskon.hr>

Commit 92df3a72 ("mm: vmscan: throttle reclaim if encountering too
many dirty pages under writeback") introduced waiting on congested zones
based on a sane algorithm in shrink_inactive_list().

What this means is that there's no more need for throttling and
additional heuristics in balance_pgdat().  So, let's remove it and tidy
up the code.
Signed-off-by: default avatarZlatko Calusic <zlatko.calusic@iskon.hr>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4db0e950
......@@ -36,7 +36,6 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
#endif
PGINODESTEAL, SLABS_SCANNED, KSWAPD_INODESTEAL,
KSWAPD_LOW_WMARK_HIT_QUICKLY, KSWAPD_HIGH_WMARK_HIT_QUICKLY,
KSWAPD_SKIP_CONGESTION_WAIT,
PAGEOUTRUN, ALLOCSTALL, PGROTATED,
#ifdef CONFIG_NUMA_BALANCING
NUMA_PTE_UPDATES,
......
......@@ -2617,7 +2617,6 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
int *classzone_idx)
{
bool pgdat_is_balanced = false;
struct zone *unbalanced_zone;
int i;
int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */
unsigned long total_scanned;
......@@ -2648,9 +2647,6 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
do {
unsigned long lru_pages = 0;
int has_under_min_watermark_zone = 0;
unbalanced_zone = NULL;
/*
* Scan in the highmem->dma direction for the highest
......@@ -2790,17 +2786,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
continue;
}
if (!zone_balanced(zone, testorder, 0, end_zone)) {
unbalanced_zone = zone;
/*
* We are still under min water mark. This
* means that we have a GFP_ATOMIC allocation
* failure risk. Hurry up!
*/
if (!zone_watermark_ok_safe(zone, order,
min_wmark_pages(zone), end_zone, 0))
has_under_min_watermark_zone = 1;
} else {
if (zone_balanced(zone, testorder, 0, end_zone))
/*
* If a zone reaches its high watermark,
* consider it to be no longer congested. It's
......@@ -2811,8 +2797,6 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
zone_clear_flag(zone, ZONE_CONGESTED);
}
}
/*
* If the low watermark is met there is no need for processes
* to be throttled on pfmemalloc_wait as they should not be
......@@ -2827,17 +2811,6 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
break; /* kswapd: all done */
}
/*
* OK, kswapd is getting into trouble. Take a nap, then take
* another pass across the zones.
*/
if (total_scanned && (sc.priority < DEF_PRIORITY - 2)) {
if (has_under_min_watermark_zone)
count_vm_event(KSWAPD_SKIP_CONGESTION_WAIT);
else if (unbalanced_zone)
wait_iff_congested(unbalanced_zone, BLK_RW_ASYNC, HZ/10);
}
/*
* We do this so kswapd doesn't build up large priorities for
* example when it is freeing in parallel with allocators. It
......
......@@ -770,7 +770,6 @@ const char * const vmstat_text[] = {
"kswapd_inodesteal",
"kswapd_low_wmark_hit_quickly",
"kswapd_high_wmark_hit_quickly",
"kswapd_skip_congestion_wait",
"pageoutrun",
"allocstall",
......
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