Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756552Ab3CMQm5 (ORCPT ); Wed, 13 Mar 2013 12:42:57 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:22736 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756517Ab3CMQm4 convert rfc822-to-8bit (ORCPT ); Wed, 13 Mar 2013 12:42:56 -0400 MIME-Version: 1.0 Message-ID: <634487ea-fbbd-4eb9-9a18-9206edc4e0d2@default> Date: Wed, 13 Mar 2013 09:42:16 -0700 (PDT) From: Dan Magenheimer To: Wanpeng Li , Andrew Morton Cc: Greg Kroah-Hartman , Dan Magenheimer , Seth Jennings , Konrad Rzeszutek Wilk , Minchan Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: RE: [PATCH 4/4] zcache: add pageframes count once compress zero-filled pages twice References: <<1363158321-20790-1-git-send-email-liwanp@linux.vnet.ibm.com>> <<1363158321-20790-5-git-send-email-liwanp@linux.vnet.ibm.com>> In-Reply-To: <<1363158321-20790-5-git-send-email-liwanp@linux.vnet.ibm.com>> X-Priority: 3 X-Mailer: Oracle Beehive Extensions for Outlook 2.0.1.7 (607090) [OL 12.0.6665.5003 (x86)] Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4049 Lines: 109 > From: Wanpeng Li [mailto:liwanp@linux.vnet.ibm.com] > Sent: Wednesday, March 13, 2013 1:05 AM > To: Andrew Morton > Cc: Greg Kroah-Hartman; Dan Magenheimer; Seth Jennings; Konrad Rzeszutek Wilk; Minchan Kim; linux- > mm@kvack.org; linux-kernel@vger.kernel.org; Wanpeng Li > Subject: [PATCH 4/4] zcache: add pageframes count once compress zero-filled pages twice Hi Wanpeng -- Thanks for taking on this task from the drivers/staging/zcache TODO list! > Since zbudpage consist of two zpages, two zero-filled pages compression > contribute to one [eph|pers]pageframe count accumulated. I'm not sure why this is necessary. The [eph|pers]pageframe count is supposed to be counting actual pageframes used by zcache. Since your patch eliminates the need to store zero pages, no pageframes are needed at all to store zero pages, so it's not necessary to increment zcache_[eph|pers]_pageframes when storing zero pages. Or am I misunderstanding your intent? Thanks, Dan > Signed-off-by: Wanpeng Li > --- > drivers/staging/zcache/zcache-main.c | 25 +++++++++++++++++++++++-- > 1 files changed, 23 insertions(+), 2 deletions(-) > > diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c > index dd52975..7860ff0 100644 > --- a/drivers/staging/zcache/zcache-main.c > +++ b/drivers/staging/zcache/zcache-main.c > @@ -544,6 +544,8 @@ static struct page *zcache_evict_eph_pageframe(void); > static void *zcache_pampd_eph_create(char *data, size_t size, bool raw, > struct tmem_handle *th) > { > + static ssize_t second_eph_zero_page; > + static atomic_t second_eph_zero_page_atomic = ATOMIC_INIT(0); > void *pampd = NULL, *cdata = data; > unsigned clen = size; > bool zero_filled = false; > @@ -561,7 +563,14 @@ static void *zcache_pampd_eph_create(char *data, size_t size, bool raw, > clen = 0; > zero_filled = true; > zcache_pages_zero++; > - goto got_pampd; > + second_eph_zero_page = atomic_inc_return( > + &second_eph_zero_page_atomic); > + if (second_eph_zero_page % 2 == 1) > + goto got_pampd; > + else { > + atomic_sub(2, &second_eph_zero_page_atomic); > + goto count_zero_page; > + } > } > kunmap_atomic(user_mem); > > @@ -597,6 +606,7 @@ static void *zcache_pampd_eph_create(char *data, size_t size, bool raw, > create_in_new_page: > pampd = (void *)zbud_create_prep(th, true, cdata, clen, newpage); > BUG_ON(pampd == NULL); > +count_zero_page: > zcache_eph_pageframes = > atomic_inc_return(&zcache_eph_pageframes_atomic); > if (zcache_eph_pageframes > zcache_eph_pageframes_max) > @@ -621,6 +631,8 @@ out: > static void *zcache_pampd_pers_create(char *data, size_t size, bool raw, > struct tmem_handle *th) > { > + static ssize_t second_pers_zero_page; > + static atomic_t second_pers_zero_page_atomic = ATOMIC_INIT(0); > void *pampd = NULL, *cdata = data; > unsigned clen = size, zero_filled = 0; > struct page *page = (struct page *)(data), *newpage; > @@ -644,7 +656,15 @@ static void *zcache_pampd_pers_create(char *data, size_t size, bool raw, > clen = 0; > zero_filled = 1; > zcache_pages_zero++; > - goto got_pampd; > + second_pers_zero_page = atomic_inc_return( > + &second_pers_zero_page_atomic); > + if (second_pers_zero_page % 2 == 1) > + goto got_pampd; > + else { > + atomic_sub(2, &second_pers_zero_page_atomic); > + goto count_zero_page; > + } > + > } > kunmap_atomic(user_mem); > > @@ -698,6 +718,7 @@ create_pampd: > create_in_new_page: > pampd = (void *)zbud_create_prep(th, false, cdata, clen, newpage); > BUG_ON(pampd == NULL); > +count_zero_page: > zcache_pers_pageframes = > atomic_inc_return(&zcache_pers_pageframes_atomic); > if (zcache_pers_pageframes > zcache_pers_pageframes_max) > -- > 1.7.7.6 -- 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/