Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752137Ab0KWHRA (ORCPT ); Tue, 23 Nov 2010 02:17:00 -0500 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:37360 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752009Ab0KWHQ6 (ORCPT ); Tue, 23 Nov 2010 02:16:58 -0500 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Minchan Kim Subject: Re: [RFC 1/2] deactive invalidated pages Cc: kosaki.motohiro@jp.fujitsu.com, Andrew Morton , linux-mm , LKML , Peter Zijlstra , Rik van Riel , Johannes Weiner , Nick Piggin In-Reply-To: References: Message-Id: <20101122143817.E242.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-2022-JP" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Tue, 23 Nov 2010 16:16:55 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6355 Lines: 209 > By Other approach, app developer uses POSIX_FADV_DONTNEED. > But it has a problem. If kernel meets page is writing > during invalidate_mapping_pages, it can't work. > It is very hard for application programmer to use it. > Because they always have to sync data before calling > fadivse(..POSIX_FADV_DONTNEED) to make sure the pages could > be discardable. At last, they can't use deferred write of kernel > so that they could see performance loss. > (http://insights.oetiker.ch/linux/fadvise.html) If rsync use the above url patch, we don't need your patch. fdatasync() + POSIX_FADV_DONTNEED should work fine. So, I think the core worth of previous PeterZ's patch is in readahead based heuristics. I'm curious why you drop it. > In fact, invalidate is very big hint to reclaimer. > It means we don't use the page any more. So let's move > the writing page into inactive list's head. But, I agree this. > > If it is real working set, it could have a enough time to > activate the page since we always try to keep many pages in > inactive list. > > I reuse lru_demote of Peter with some change. > > Reported-by: Ben Gamari > Signed-off-by: Minchan Kim > Signed-off-by: Peter Zijlstra > Cc: Rik van Riel > Cc: KOSAKI Motohiro > Cc: Johannes Weiner > Cc: Nick Piggin > > Ben, Remain thing is to modify rsync and use > fadvise(POSIX_FADV_DONTNEED). Could you test it? > --- > include/linux/swap.h | 1 + > mm/swap.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++ > mm/truncate.c | 11 +++++--- > 3 files changed, 69 insertions(+), 4 deletions(-) > > diff --git a/include/linux/swap.h b/include/linux/swap.h > index eba53e7..a3c9248 100644 > --- a/include/linux/swap.h > +++ b/include/linux/swap.h > @@ -213,6 +213,7 @@ extern void mark_page_accessed(struct page *); > extern void lru_add_drain(void); > extern int lru_add_drain_all(void); > extern void rotate_reclaimable_page(struct page *page); > +extern void lru_deactive_page(struct page *page); > extern void swap_setup(void); > > extern void add_page_to_unevictable_list(struct page *page); > diff --git a/mm/swap.c b/mm/swap.c > index 3f48542..56fa298 100644 > --- a/mm/swap.c > +++ b/mm/swap.c > @@ -39,6 +39,8 @@ int page_cluster; > > static DEFINE_PER_CPU(struct pagevec[NR_LRU_LISTS], lru_add_pvecs); > static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs); > +static DEFINE_PER_CPU(struct pagevec, lru_deactive_pvecs); > + > > /* > * This path almost never happens for VM activity - pages are normally > @@ -266,6 +268,45 @@ void add_page_to_unevictable_list(struct page *page) > spin_unlock_irq(&zone->lru_lock); > } > > +static void __pagevec_lru_deactive(struct pagevec *pvec) > +{ > + int i, lru, file; > + > + struct zone *zone = NULL; > + > + for (i = 0; i < pagevec_count(pvec); i++) { > + struct page *page = pvec->pages[i]; > + struct zone *pagezone = page_zone(page); > + > + if (pagezone != zone) { > + if (zone) > + spin_unlock_irq(&zone->lru_lock); > + zone = pagezone; > + spin_lock_irq(&zone->lru_lock); > + } > + > + if (PageLRU(page)) { > + if (PageActive(page)) { > + file = page_is_file_cache(page); > + lru = page_lru_base_type(page); > + del_page_from_lru_list(zone, page, > + lru + LRU_ACTIVE); > + ClearPageActive(page); > + ClearPageReferenced(page); > + add_page_to_lru_list(zone, page, lru); > + __count_vm_event(PGDEACTIVATE); > + > + update_page_reclaim_stat(zone, page, file, 0); When PageActive is unset, we need to change cgroup lru too. > + } > + } > + } > + if (zone) > + spin_unlock_irq(&zone->lru_lock); > + > + release_pages(pvec->pages, pvec->nr, pvec->cold); > + pagevec_reinit(pvec); > +} > + > /* > * Drain pages out of the cpu's pagevecs. > * Either "cpu" is the current CPU, and preemption has already been > @@ -292,8 +333,28 @@ static void drain_cpu_pagevecs(int cpu) > pagevec_move_tail(pvec); > local_irq_restore(flags); > } > + > + pvec = &per_cpu(lru_deactive_pvecs, cpu); > + if (pagevec_count(pvec)) > + __pagevec_lru_deactive(pvec); > +} > + > +/* > + * Function used to forecefully demote a page to the head of the inactive > + * list. > + */ > +void lru_deactive_page(struct page *page) > +{ > + if (likely(get_page_unless_zero(page))) { Probably, we can check PageLRU and PageActive here too. It help to avoid unnecessary batching and may slightly increase performance. > + struct pagevec *pvec = &get_cpu_var(lru_deactive_pvecs); > + > + if (!pagevec_add(pvec, page)) > + __pagevec_lru_deactive(pvec); > + put_cpu_var(lru_deactive_pvecs); > + } > } > > + > void lru_add_drain(void) > { > drain_cpu_pagevecs(get_cpu()); > diff --git a/mm/truncate.c b/mm/truncate.c > index cd94607..c73fb19 100644 > --- a/mm/truncate.c > +++ b/mm/truncate.c > @@ -332,7 +332,8 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping, > { > struct pagevec pvec; > pgoff_t next = start; > - unsigned long ret = 0; > + unsigned long ret; > + unsigned long count = 0; > int i; > > pagevec_init(&pvec, 0); > @@ -359,8 +360,10 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping, > if (lock_failed) > continue; > > - ret += invalidate_inode_page(page); > - > + ret = invalidate_inode_page(page); > + if (!ret) > + lru_deactive_page(page); > + count += ret; > unlock_page(page); > if (next > end) > break; > @@ -369,7 +372,7 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping, > mem_cgroup_uncharge_end(); > cond_resched(); > } > - return ret; > + return count; > } > EXPORT_SYMBOL(invalidate_mapping_pages); > > -- > 1.7.0.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/