Commit 3db65812 authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds

Revert "mm, vmscan: account for skipped pages as a partial scan"

This reverts commit d7f05528.

Now that reclaimability of a node is no longer based on the ratio
between pages scanned and theoretically reclaimable pages, we can remove
accounting tricks for pages skipped due to zone constraints.

Link: http://lkml.kernel.org/r/20170228214007.5621-9-hannes@cmpxchg.orgSigned-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarHillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Jia He <hejianet@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c822f622
......@@ -1472,12 +1472,12 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
unsigned long nr_taken = 0;
unsigned long nr_zone_taken[MAX_NR_ZONES] = { 0 };
unsigned long nr_skipped[MAX_NR_ZONES] = { 0, };
unsigned long skipped = 0, total_skipped = 0;
unsigned long skipped = 0;
unsigned long scan, nr_pages;
LIST_HEAD(pages_skipped);
for (scan = 0; scan < nr_to_scan && nr_taken < nr_to_scan &&
!list_empty(src);) {
!list_empty(src); scan++) {
struct page *page;
page = lru_to_page(src);
......@@ -1491,12 +1491,6 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
continue;
}
/*
* Account for scanned and skipped separetly to avoid the pgdat
* being prematurely marked unreclaimable by pgdat_reclaimable.
*/
scan++;
switch (__isolate_lru_page(page, mode)) {
case 0:
nr_pages = hpage_nr_pages(page);
......@@ -1525,6 +1519,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
if (!list_empty(&pages_skipped)) {
int zid;
list_splice(&pages_skipped, src);
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
if (!nr_skipped[zid])
continue;
......@@ -1532,17 +1527,8 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
__count_zid_vm_events(PGSCAN_SKIP, zid, nr_skipped[zid]);
skipped += nr_skipped[zid];
}
/*
* Account skipped pages as a partial scan as the pgdat may be
* close to unreclaimable. If the LRU list is empty, account
* skipped pages as a full scan.
*/
total_skipped = list_empty(src) ? skipped : skipped >> 2;
list_splice(&pages_skipped, src);
}
*nr_scanned = scan + total_skipped;
*nr_scanned = scan;
trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan,
scan, skipped, nr_taken, mode, lru);
update_lru_sizes(lruvec, lru, nr_zone_taken);
......
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