From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id AE3D76B006A for ; Mon, 11 Jan 2010 00:23:21 -0500 (EST) Received: by gxk24 with SMTP id 24so21159821gxk.6 for ; Sun, 10 Jan 2010 21:23:20 -0800 (PST) Date: Mon, 11 Jan 2010 14:20:59 +0900 From: Minchan Kim Subject: Re: [PATCH 4/4] mm/page_alloc : relieve zone->lock's pressure for memory free Message-Id: <20100111142059.ae4fb643.minchan.kim@barrios-desktop> In-Reply-To: <1263184634-15447-4-git-send-email-shijie8@gmail.com> References: <1263184634-15447-1-git-send-email-shijie8@gmail.com> <1263184634-15447-2-git-send-email-shijie8@gmail.com> <1263184634-15447-3-git-send-email-shijie8@gmail.com> <1263184634-15447-4-git-send-email-shijie8@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Huang Shijie Cc: akpm@linux-foundation.org, mel@csn.ul.ie, kosaki.motohiro@jp.fujitsu.com, linux-mm@kvack.org List-ID: On Mon, 11 Jan 2010 12:37:14 +0800 Huang Shijie wrote: > Move the __mod_zone_page_state out the guard region of > the spinlock to relieve the pressure for memory free. > > Signed-off-by: Huang Shijie > --- > mm/page_alloc.c | 26 ++++++++++++++++---------- > 1 files changed, 16 insertions(+), 10 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 290dfc3..34b9a3a 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -530,12 +530,9 @@ static void free_pcppages_bulk(struct zone *zone, int count, > { > int migratetype = 0; > int batch_free = 0; > + int free_ok = 0; > > spin_lock(&zone->lock); > - zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE); > - zone->pages_scanned = 0; We don't use zone->lock to protect pages_scanned in shrink_[in]active_list. At least, we can move zone->pages_scanned out of lock. In addition, sometime we don't use lock to test ZONE_ALL_UNRECLAIMABLE, sometime we do use zone->lock(ex, zoneinfo_show_print). Now lock for ZONE_ALL_UNRECLAIMABLE is not consistent, I think we have to use not zone->lock but zone->lru_lock since it's related to reclaim. Few days ago, Mel and Kosaki discussed about zone->lock. Any thought? > - > - __mod_zone_page_state(zone, NR_FREE_PAGES, count); > while (count) { > struct page *page; > struct list_head *list; > @@ -558,23 +555,32 @@ static void free_pcppages_bulk(struct zone *zone, int count, > page = list_entry(list->prev, struct page, lru); > /* must delete as __free_one_page list manipulates */ > list_del(&page->lru); > - __free_one_page(page, zone, 0, migratetype); > + free_ok += __free_one_page(page, zone, 0, migratetype); > trace_mm_page_pcpu_drain(page, 0, migratetype); > } while (--count && --batch_free && !list_empty(list)); > } > + > + if (likely(free_ok)) { > + zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE); > + zone->pages_scanned = 0; > + } > spin_unlock(&zone->lock); > + __mod_zone_page_state(zone, NR_FREE_PAGES, free_ok); > } > > static void free_one_page(struct zone *zone, struct page *page, int order, > int migratetype) > { > - spin_lock(&zone->lock); > - zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE); > - zone->pages_scanned = 0; > + int free_ok; > > - __mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order); > - __free_one_page(page, zone, order, migratetype); > + spin_lock(&zone->lock); > + free_ok = __free_one_page(page, zone, order, migratetype); > + if (likely(free_ok)) { > + zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE); > + zone->pages_scanned = 0; > + } > spin_unlock(&zone->lock); > + __mod_zone_page_state(zone, NR_FREE_PAGES, free_ok << order); > } > > static void __free_pages_ok(struct page *page, unsigned int order) > -- > 1.6.5.2 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org -- Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org