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author | Shaohua Li <shaohua.li@intel.com> | 2011-01-13 15:47:34 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-13 17:32:50 -0800 |
commit | 744ed1442757767ffede5008bb13e0805085902e (patch) | |
tree | 75af93524570b40056f2367059dfa84ba7d90186 /mm | |
parent | d8505dee1a87b8d41b9c4ee1325cd72258226fbc (diff) | |
download | kernel_samsung_crespo-744ed1442757767ffede5008bb13e0805085902e.zip kernel_samsung_crespo-744ed1442757767ffede5008bb13e0805085902e.tar.gz kernel_samsung_crespo-744ed1442757767ffede5008bb13e0805085902e.tar.bz2 |
mm: batch activate_page() to reduce lock contention
The zone->lru_lock is heavily contented in workload where activate_page()
is frequently used. We could do batch activate_page() to reduce the lock
contention. The batched pages will be added into zone list when the pool
is full or page reclaim is trying to drain them.
For example, in a 4 socket 64 CPU system, create a sparse file and 64
processes, processes shared map to the file. Each process read access the
whole file and then exit. The process exit will do unmap_vmas() and cause
a lot of activate_page() call. In such workload, we saw about 58% total
time reduction with below patch. Other workloads with a lot of
activate_page also benefits a lot too.
I tested some microbenchmarks:
case-anon-cow-rand-mt 0.58%
case-anon-cow-rand -3.30%
case-anon-cow-seq-mt -0.51%
case-anon-cow-seq -5.68%
case-anon-r-rand-mt 0.23%
case-anon-r-rand 0.81%
case-anon-r-seq-mt -0.71%
case-anon-r-seq -1.99%
case-anon-rx-rand-mt 2.11%
case-anon-rx-seq-mt 3.46%
case-anon-w-rand-mt -0.03%
case-anon-w-rand -0.50%
case-anon-w-seq-mt -1.08%
case-anon-w-seq -0.12%
case-anon-wx-rand-mt -5.02%
case-anon-wx-seq-mt -1.43%
case-fork 1.65%
case-fork-sleep -0.07%
case-fork-withmem 1.39%
case-hugetlb -0.59%
case-lru-file-mmap-read-mt -0.54%
case-lru-file-mmap-read 0.61%
case-lru-file-mmap-read-rand -2.24%
case-lru-file-readonce -0.64%
case-lru-file-readtwice -11.69%
case-lru-memcg -1.35%
case-mmap-pread-rand-mt 1.88%
case-mmap-pread-rand -15.26%
case-mmap-pread-seq-mt 0.89%
case-mmap-pread-seq -69.72%
case-mmap-xread-rand-mt 0.71%
case-mmap-xread-seq-mt 0.38%
The most significent are:
case-lru-file-readtwice -11.69%
case-mmap-pread-rand -15.26%
case-mmap-pread-seq -69.72%
which use activate_page a lot. others are basically variations because
each run has slightly difference.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/internal.h | 9 | ||||
-rw-r--r-- | mm/swap.c | 90 | ||||
-rw-r--r-- | mm/vmscan.c | 6 |
3 files changed, 92 insertions, 13 deletions
diff --git a/mm/internal.h b/mm/internal.h index 6948820..4c98630 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -39,6 +39,15 @@ static inline void __put_page(struct page *page) extern unsigned long highest_memmap_pfn; +#ifdef CONFIG_SMP +extern int putback_active_lru_page(struct zone *zone, struct page *page); +#else +static inline int putback_active_lru_page(struct zone *zone, struct page *page) +{ + return 0; +} +#endif + /* * in mm/vmscan.c: */ @@ -271,27 +271,94 @@ static void update_page_reclaim_stat(struct zone *zone, struct page *page, } /* - * FIXME: speed this up? + * A page will go to active list either by activate_page or putback_lru_page. + * In the activate_page case, the page hasn't active bit set. The page might + * not in LRU list because it's isolated before it gets a chance to be moved to + * active list. The window is small because pagevec just stores several pages. + * For such case, we do nothing for such page. + * In the putback_lru_page case, the page isn't in lru list but has active + * bit set */ -void activate_page(struct page *page) +static void __activate_page(struct page *page, void *arg) { struct zone *zone = page_zone(page); + int file = page_is_file_cache(page); + int lru = page_lru_base_type(page); + bool putback = !PageLRU(page); - spin_lock_irq(&zone->lru_lock); - if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { - int file = page_is_file_cache(page); - int lru = page_lru_base_type(page); + /* The page is isolated before it's moved to active list */ + if (!PageLRU(page) && !PageActive(page)) + return; + if ((PageLRU(page) && PageActive(page)) || PageUnevictable(page)) + return; + + if (!putback) del_page_from_lru_list(zone, page, lru); + else + SetPageLRU(page); - SetPageActive(page); - lru += LRU_ACTIVE; - add_page_to_lru_list(zone, page, lru); - __count_vm_event(PGACTIVATE); + SetPageActive(page); + lru += LRU_ACTIVE; + add_page_to_lru_list(zone, page, lru); + + if (putback) + return; + __count_vm_event(PGACTIVATE); + update_page_reclaim_stat(zone, page, file, 1); +} + +#ifdef CONFIG_SMP +static DEFINE_PER_CPU(struct pagevec, activate_page_pvecs); + +static void activate_page_drain(int cpu) +{ + struct pagevec *pvec = &per_cpu(activate_page_pvecs, cpu); + + if (pagevec_count(pvec)) + pagevec_lru_move_fn(pvec, __activate_page, NULL); +} + +void activate_page(struct page *page) +{ + if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { + struct pagevec *pvec = &get_cpu_var(activate_page_pvecs); + + page_cache_get(page); + if (!pagevec_add(pvec, page)) + pagevec_lru_move_fn(pvec, __activate_page, NULL); + put_cpu_var(activate_page_pvecs); + } +} - update_page_reclaim_stat(zone, page, file, 1); +/* Caller should hold zone->lru_lock */ +int putback_active_lru_page(struct zone *zone, struct page *page) +{ + struct pagevec *pvec = &get_cpu_var(activate_page_pvecs); + + if (!pagevec_add(pvec, page)) { + spin_unlock_irq(&zone->lru_lock); + pagevec_lru_move_fn(pvec, __activate_page, NULL); + spin_lock_irq(&zone->lru_lock); } + put_cpu_var(activate_page_pvecs); + return 1; +} + +#else +static inline void activate_page_drain(int cpu) +{ +} + +void activate_page(struct page *page) +{ + struct zone *zone = page_zone(page); + + spin_lock_irq(&zone->lru_lock); + if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) + __activate_page(page, NULL); spin_unlock_irq(&zone->lru_lock); } +#endif /* * Mark a page as having seen activity. @@ -390,6 +457,7 @@ static void drain_cpu_pagevecs(int cpu) pagevec_move_tail(pvec); local_irq_restore(flags); } + activate_page_drain(cpu); } void lru_add_drain(void) diff --git a/mm/vmscan.c b/mm/vmscan.c index 47a5096..99999a9 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1271,14 +1271,16 @@ putback_lru_pages(struct zone *zone, struct scan_control *sc, spin_lock_irq(&zone->lru_lock); continue; } - SetPageLRU(page); lru = page_lru(page); - add_page_to_lru_list(zone, page, lru); if (is_active_lru(lru)) { int file = is_file_lru(lru); int numpages = hpage_nr_pages(page); reclaim_stat->recent_rotated[file] += numpages; + if (putback_active_lru_page(zone, page)) + continue; } + SetPageLRU(page); + add_page_to_lru_list(zone, page, lru); if (!pagevec_add(&pvec, page)) { spin_unlock_irq(&zone->lru_lock); __pagevec_release(&pvec); |