| Message ID | 20171018075952.10627-2-mgorman@techsingularity.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 10/18/2017 09:59 AM, Mel Gorman wrote: > Freeing a list of pages current enables/disables IRQs for each page freed. > This patch splits freeing a list of pages into two operations -- preparing > the pages for freeing and the actual freeing. This is a tradeoff - we're > taking two passes of the list to free in exchange for avoiding multiple > enable/disable of IRQs. There's also some overhead of storing pfn in page->private, but all that seems negligible compared to irq disable/enable... > sparsetruncate (tiny) > 4.14.0-rc4 4.14.0-rc4 > janbatch-v1r1 oneirq-v1r1 > Min Time 149.00 ( 0.00%) 141.00 ( 5.37%) > 1st-qrtle Time 150.00 ( 0.00%) 142.00 ( 5.33%) > 2nd-qrtle Time 151.00 ( 0.00%) 142.00 ( 5.96%) > 3rd-qrtle Time 151.00 ( 0.00%) 143.00 ( 5.30%) > Max-90% Time 153.00 ( 0.00%) 144.00 ( 5.88%) > Max-95% Time 155.00 ( 0.00%) 147.00 ( 5.16%) > Max-99% Time 201.00 ( 0.00%) 195.00 ( 2.99%) > Max Time 236.00 ( 0.00%) 230.00 ( 2.54%) > Amean Time 152.65 ( 0.00%) 144.37 ( 5.43%) > Stddev Time 9.78 ( 0.00%) 10.44 ( -6.72%) > Coeff Time 6.41 ( 0.00%) 7.23 ( -12.84%) > Best99%Amean Time 152.07 ( 0.00%) 143.72 ( 5.50%) > Best95%Amean Time 150.75 ( 0.00%) 142.37 ( 5.56%) > Best90%Amean Time 150.59 ( 0.00%) 142.19 ( 5.58%) > Best75%Amean Time 150.36 ( 0.00%) 141.92 ( 5.61%) > Best50%Amean Time 150.04 ( 0.00%) 141.69 ( 5.56%) > Best25%Amean Time 149.85 ( 0.00%) 141.38 ( 5.65%) > > With a tiny number of files, each file truncated has resident page cache > and it shows that time to truncate is roughtly 5-6% with some minor jitter. > > 4.14.0-rc4 4.14.0-rc4 > janbatch-v1r1 oneirq-v1r1 > Hmean SeqCreate ops 65.27 ( 0.00%) 81.86 ( 25.43%) > Hmean SeqCreate read 39.48 ( 0.00%) 47.44 ( 20.16%) > Hmean SeqCreate del 24963.95 ( 0.00%) 26319.99 ( 5.43%) > Hmean RandCreate ops 65.47 ( 0.00%) 82.01 ( 25.26%) > Hmean RandCreate read 42.04 ( 0.00%) 51.75 ( 23.09%) > Hmean RandCreate del 23377.66 ( 0.00%) 23764.79 ( 1.66%) > > As expected, there is a small gain for the delete operation. Looks good. > Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> A nit below. > @@ -2647,11 +2663,25 @@ void free_hot_cold_page(struct page *page, bool cold) > void free_hot_cold_page_list(struct list_head *list, bool cold) > { > struct page *page, *next; > + unsigned long flags, pfn; > + > + /* Prepare pages for freeing */ > + list_for_each_entry_safe(page, next, list, lru) { > + pfn = page_to_pfn(page); > + if (!free_hot_cold_page_prepare(page, pfn)) > + list_del(&page->lru); > + page->private = pfn; We have (set_)page_private() helpers so better to use them (makes it a bit easier to check for all places where page->private is used to e.g. avoid a clash)? > + } > > + local_irq_save(flags); > list_for_each_entry_safe(page, next, list, lru) { > + unsigned long pfn = page->private; > + > + page->private = 0; Same here. > trace_mm_page_free_batched(page, cold); > - free_hot_cold_page(page, cold); > + free_hot_cold_page_commit(page, pfn, cold); > } > + local_irq_restore(flags); > } > > /* >
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 77e4d3c5c57b..167e163cf733 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2590,24 +2590,26 @@ void mark_free_pages(struct zone *zone) } #endif /* CONFIG_PM */ -/* - * Free a 0-order page - * cold == true ? free a cold page : free a hot page - */ -void free_hot_cold_page(struct page *page, bool cold) +static bool free_hot_cold_page_prepare(struct page *page, unsigned long pfn) { - struct zone *zone = page_zone(page); - struct per_cpu_pages *pcp; - unsigned long flags; - unsigned long pfn = page_to_pfn(page); int migratetype; if (!free_pcp_prepare(page)) - return; + return false; migratetype = get_pfnblock_migratetype(page, pfn); set_pcppage_migratetype(page, migratetype); - local_irq_save(flags); + return true; +} + +static void free_hot_cold_page_commit(struct page *page, unsigned long pfn, + bool cold) +{ + struct zone *zone = page_zone(page); + struct per_cpu_pages *pcp; + int migratetype; + + migratetype = get_pcppage_migratetype(page); __count_vm_event(PGFREE); /* @@ -2620,7 +2622,7 @@ void free_hot_cold_page(struct page *page, bool cold) if (migratetype >= MIGRATE_PCPTYPES) { if (unlikely(is_migrate_isolate(migratetype))) { free_one_page(zone, page, pfn, 0, migratetype); - goto out; + return; } migratetype = MIGRATE_MOVABLE; } @@ -2636,8 +2638,22 @@ void free_hot_cold_page(struct page *page, bool cold) free_pcppages_bulk(zone, batch, pcp); pcp->count -= batch; } +} -out: +/* + * Free a 0-order page + * cold == true ? free a cold page : free a hot page + */ +void free_hot_cold_page(struct page *page, bool cold) +{ + unsigned long flags; + unsigned long pfn = page_to_pfn(page); + + if (!free_hot_cold_page_prepare(page, pfn)) + return; + + local_irq_save(flags); + free_hot_cold_page_commit(page, pfn, cold); local_irq_restore(flags); } @@ -2647,11 +2663,25 @@ void free_hot_cold_page(struct page *page, bool cold) void free_hot_cold_page_list(struct list_head *list, bool cold) { struct page *page, *next; + unsigned long flags, pfn; + + /* Prepare pages for freeing */ + list_for_each_entry_safe(page, next, list, lru) { + pfn = page_to_pfn(page); + if (!free_hot_cold_page_prepare(page, pfn)) + list_del(&page->lru); + page->private = pfn; + } + local_irq_save(flags); list_for_each_entry_safe(page, next, list, lru) { + unsigned long pfn = page->private; + + page->private = 0; trace_mm_page_free_batched(page, cold); - free_hot_cold_page(page, cold); + free_hot_cold_page_commit(page, pfn, cold); } + local_irq_restore(flags); } /*
Freeing a list of pages current enables/disables IRQs for each page freed. This patch splits freeing a list of pages into two operations -- preparing the pages for freeing and the actual freeing. This is a tradeoff - we're taking two passes of the list to free in exchange for avoiding multiple enable/disable of IRQs. sparsetruncate (tiny) 4.14.0-rc4 4.14.0-rc4 janbatch-v1r1 oneirq-v1r1 Min Time 149.00 ( 0.00%) 141.00 ( 5.37%) 1st-qrtle Time 150.00 ( 0.00%) 142.00 ( 5.33%) 2nd-qrtle Time 151.00 ( 0.00%) 142.00 ( 5.96%) 3rd-qrtle Time 151.00 ( 0.00%) 143.00 ( 5.30%) Max-90% Time 153.00 ( 0.00%) 144.00 ( 5.88%) Max-95% Time 155.00 ( 0.00%) 147.00 ( 5.16%) Max-99% Time 201.00 ( 0.00%) 195.00 ( 2.99%) Max Time 236.00 ( 0.00%) 230.00 ( 2.54%) Amean Time 152.65 ( 0.00%) 144.37 ( 5.43%) Stddev Time 9.78 ( 0.00%) 10.44 ( -6.72%) Coeff Time 6.41 ( 0.00%) 7.23 ( -12.84%) Best99%Amean Time 152.07 ( 0.00%) 143.72 ( 5.50%) Best95%Amean Time 150.75 ( 0.00%) 142.37 ( 5.56%) Best90%Amean Time 150.59 ( 0.00%) 142.19 ( 5.58%) Best75%Amean Time 150.36 ( 0.00%) 141.92 ( 5.61%) Best50%Amean Time 150.04 ( 0.00%) 141.69 ( 5.56%) Best25%Amean Time 149.85 ( 0.00%) 141.38 ( 5.65%) With a tiny number of files, each file truncated has resident page cache and it shows that time to truncate is roughtly 5-6% with some minor jitter. 4.14.0-rc4 4.14.0-rc4 janbatch-v1r1 oneirq-v1r1 Hmean SeqCreate ops 65.27 ( 0.00%) 81.86 ( 25.43%) Hmean SeqCreate read 39.48 ( 0.00%) 47.44 ( 20.16%) Hmean SeqCreate del 24963.95 ( 0.00%) 26319.99 ( 5.43%) Hmean RandCreate ops 65.47 ( 0.00%) 82.01 ( 25.26%) Hmean RandCreate read 42.04 ( 0.00%) 51.75 ( 23.09%) Hmean RandCreate del 23377.66 ( 0.00%) 23764.79 ( 1.66%) As expected, there is a small gain for the delete operation. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> --- mm/page_alloc.c | 58 +++++++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 44 insertions(+), 14 deletions(-)