The patch titled
vmscan: cleanup the scan batching code
has been added to the -mm tree. Its filename is
vmscan-cleanup-the-scan-batching-code.patch
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out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: vmscan: cleanup the scan batching code
From: Wu Fengguang <fengguang.wu@xxxxxxxxx>
The vmscan batching logic is twisting. Move it into a standalone function
nr_scan_try_batch() and document it. No behavior change.
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Nick Piggin <npiggin@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mmzone.h | 4 ++--
mm/page_alloc.c | 2 +-
mm/vmscan.c | 39 ++++++++++++++++++++++++++++-----------
mm/vmstat.c | 8 ++++----
4 files changed, 35 insertions(+), 18 deletions(-)
diff -puN include/linux/mmzone.h~vmscan-cleanup-the-scan-batching-code include/linux/mmzone.h
--- a/include/linux/mmzone.h~vmscan-cleanup-the-scan-batching-code
+++ a/include/linux/mmzone.h
@@ -326,9 +326,9 @@ struct zone {
/* Fields commonly accessed by the page reclaim scanner */
spinlock_t lru_lock;
- struct {
+ struct zone_lru {
struct list_head list;
- unsigned long nr_scan;
+ unsigned long nr_saved_scan; /* accumulated for batching */
} lru[NR_LRU_LISTS];
struct zone_reclaim_stat reclaim_stat;
diff -puN mm/page_alloc.c~vmscan-cleanup-the-scan-batching-code mm/page_alloc.c
--- a/mm/page_alloc.c~vmscan-cleanup-the-scan-batching-code
+++ a/mm/page_alloc.c
@@ -3729,7 +3729,7 @@ static void __paginginit free_area_init_
zone_pcp_init(zone);
for_each_lru(l) {
INIT_LIST_HEAD(&zone->lru[l].list);
- zone->lru[l].nr_scan = 0;
+ zone->lru[l].nr_saved_scan = 0;
}
zone->reclaim_stat.recent_rotated[0] = 0;
zone->reclaim_stat.recent_rotated[1] = 0;
diff -puN mm/vmscan.c~vmscan-cleanup-the-scan-batching-code mm/vmscan.c
--- a/mm/vmscan.c~vmscan-cleanup-the-scan-batching-code
+++ a/mm/vmscan.c
@@ -1490,6 +1490,26 @@ static void get_scan_ratio(struct zone *
percent[1] = 100 - percent[0];
}
+/*
+ * Smallish @nr_to_scan's are deposited in @nr_saved_scan,
+ * until we collected @swap_cluster_max pages to scan.
+ */
+static unsigned long nr_scan_try_batch(unsigned long nr_to_scan,
+ unsigned long *nr_saved_scan,
+ unsigned long swap_cluster_max)
+{
+ unsigned long nr;
+
+ *nr_saved_scan += nr_to_scan;
+ nr = *nr_saved_scan;
+
+ if (nr >= swap_cluster_max)
+ *nr_saved_scan = 0;
+ else
+ nr = 0;
+
+ return nr;
+}
/*
* This is a basic per-zone page freer. Used by both kswapd and direct reclaim.
@@ -1515,14 +1535,11 @@ static void shrink_zone(int priority, st
scan >>= priority;
scan = (scan * percent[file]) / 100;
}
- if (scanning_global_lru(sc)) {
- zone->lru[l].nr_scan += scan;
- nr[l] = zone->lru[l].nr_scan;
- if (nr[l] >= swap_cluster_max)
- zone->lru[l].nr_scan = 0;
- else
- nr[l] = 0;
- } else
+ if (scanning_global_lru(sc))
+ nr[l] = nr_scan_try_batch(scan,
+ &zone->lru[l].nr_saved_scan,
+ swap_cluster_max);
+ else
nr[l] = scan;
}
@@ -2119,11 +2136,11 @@ static void shrink_all_zones(unsigned lo
l == LRU_ACTIVE_FILE))
continue;
- zone->lru[l].nr_scan += (lru_pages >> prio) + 1;
- if (zone->lru[l].nr_scan >= nr_pages || pass > 3) {
+ zone->lru[l].nr_saved_scan += (lru_pages >> prio) + 1;
+ if (zone->lru[l].nr_saved_scan >= nr_pages || pass > 3) {
unsigned long nr_to_scan;
- zone->lru[l].nr_scan = 0;
+ zone->lru[l].nr_saved_scan = 0;
nr_to_scan = min(nr_pages, lru_pages);
nr_reclaimed += shrink_list(l, nr_to_scan, zone,
sc, prio);
diff -puN mm/vmstat.c~vmscan-cleanup-the-scan-batching-code mm/vmstat.c
--- a/mm/vmstat.c~vmscan-cleanup-the-scan-batching-code
+++ a/mm/vmstat.c
@@ -729,10 +729,10 @@ static void zoneinfo_show_print(struct s
zone->pages_low,
zone->pages_high,
zone->pages_scanned,
- zone->lru[LRU_ACTIVE_ANON].nr_scan,
- zone->lru[LRU_INACTIVE_ANON].nr_scan,
- zone->lru[LRU_ACTIVE_FILE].nr_scan,
- zone->lru[LRU_INACTIVE_FILE].nr_scan,
+ zone->lru[LRU_ACTIVE_ANON].nr_saved_scan,
+ zone->lru[LRU_INACTIVE_ANON].nr_saved_scan,
+ zone->lru[LRU_ACTIVE_FILE].nr_saved_scan,
+ zone->lru[LRU_INACTIVE_FILE].nr_saved_scan,
zone->spanned_pages,
zone->present_pages);
_
Patches currently in -mm which might be from fengguang.wu@xxxxxxxxx are
origin.patch
inotify-use-gfp_nofs-in-kernel_event-to-work-around-a-lockdep-false-positive.patch
inotify-use-gfp_nofs-in-kernel_event-to-work-around-a-lockdep-false-positive-fix.patch
linux-next.patch
readahead-make-mmap_miss-an-unsigned-int.patch
readahead-move-max_sane_readahead-calls-into-force_page_cache_readahead.patch
readahead-apply-max_sane_readahead-limit-in-ondemand_readahead.patch
readahead-remove-one-unnecessary-radix-tree-lookup.patch
readahead-increase-interleaved-readahead-size.patch
readahead-remove-sync-async-readahead-call-dependency.patch
readahead-clean-up-and-simplify-the-code-for-filemap-page-fault-readahead.patch
readahead-sequential-mmap-readahead.patch
readahead-enforce-full-readahead-size-on-async-mmap-readahead.patch
readahead-record-mmap-read-around-states-in-file_ra_state.patch
radix-tree-add-radix_tree_prev_hole.patch
readahead-move-the-random-read-case-to-bottom.patch
readahead-introduce-context-readahead-algorithm.patch
readahead-introduce-context-readahead-algorithm-update.patch
readahead-remove-redundant-test-in-shrink_readahead_size_eio.patch
readahead-enforce-full-sync-mmap-readahead-size.patch
pagemap-document-clarifications.patch
pagemap-documentation-9-more-exported-page-flags.patch
mm-introduce-pagehuge-for-testing-huge-gigantic-pages.patch
proc-kpagecount-kpageflags-code-cleanup.patch
proc-export-more-page-flags-in-proc-kpageflags.patch
vmscan-cleanup-the-scan-batching-code.patch
vmscan-dont-export-nr_saved_scan-in-proc-zoneinfo.patch
--
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