From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759351AbZDONYT (ORCPT ); Wed, 15 Apr 2009 09:24:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754023AbZDONYF (ORCPT ); Wed, 15 Apr 2009 09:24:05 -0400 Received: from mail-fx0-f158.google.com ([209.85.220.158]:51155 "EHLO mail-fx0-f158.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753785AbZDONYC (ORCPT ); Wed, 15 Apr 2009 09:24:02 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:mail-followup-to:references :mime-version:content-type:content-disposition:in-reply-to :user-agent; b=Y+m96kvzHuNMCx/gDwgkxD7OGNtKZqiBLn18blGM6I/fbBqXiReXUmM+tKXhWMbFET r9eH030Vk5ojpyzSn7KJfcRfWP0xtEYdqspPx8BEvtDziDMZBON1iEXqDiiS+oj9lkbT 24ZoDYj/RM4etU+MyMN8c4XFTFUUVlJg6I49I= Date: Wed, 15 Apr 2009 15:23:57 +0200 From: Andrea Righi To: Ryo Tsuruta Cc: kamezawa.hiroyu@jp.fujitsu.com, menage@google.com, balbir@linux.vnet.ibm.com, guijianfeng@cn.fujitsu.com, agk@sourceware.org, akpm@linux-foundation.org, axboe@kernel.dk, baramsori72@gmail.com, chlunde@ping.uio.no, dave@linux.vnet.ibm.com, dpshah@google.com, eric.rannaud@gmail.com, fernando@oss.ntt.co.jp, taka@valinux.co.jp, lizf@cn.fujitsu.com, matt@bluehost.com, dradford@bluehost.com, ngupta@google.com, randy.dunlap@oracle.com, roberto@unbit.it, s-uchida@ap.jp.nec.com, subrata@linux.vnet.ibm.com, yoshikawa.takuya@oss.ntt.co.jp, containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/9] bio-cgroup controller Message-ID: <20090415132356.GA19270@linux> Mail-Followup-To: Ryo Tsuruta , kamezawa.hiroyu@jp.fujitsu.com, menage@google.com, balbir@linux.vnet.ibm.com, guijianfeng@cn.fujitsu.com, agk@sourceware.org, akpm@linux-foundation.org, axboe@kernel.dk, baramsori72@gmail.com, chlunde@ping.uio.no, dave@linux.vnet.ibm.com, dpshah@google.com, eric.rannaud@gmail.com, fernando@oss.ntt.co.jp, taka@valinux.co.jp, lizf@cn.fujitsu.com, matt@bluehost.com, dradford@bluehost.com, ngupta@google.com, randy.dunlap@oracle.com, roberto@unbit.it, s-uchida@ap.jp.nec.com, subrata@linux.vnet.ibm.com, yoshikawa.takuya@oss.ntt.co.jp, containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org References: <1239740480-28125-4-git-send-email-righi.andrea@gmail.com> <20090415111528.b796519a.kamezawa.hiroyu@jp.fujitsu.com> <20090415093716.GA5968@linux> <20090415.213850.226770691.ryov@valinux.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090415.213850.226770691.ryov@valinux.co.jp> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 15, 2009 at 09:38:50PM +0900, Ryo Tsuruta wrote: > Hi Andrea and Kamezawa-san, > > > Ryo, it would be great if you can look at this and fix/integrate into > > the mainstream bio-cgroup. Otherwise I can try to to schedule this in my > > work. > > O.K. I'll apply those fixes and post patches as soon as I can. > Very good! I've just tested the bio_cgroup_id inclusion in page_cgroup->flags. I'm posting the patch on-top-of my patchset. If you're interested, it should apply cleanly to the original bio-cgroup, except for the get/put_cgroup_from_page() part. Thanks, -Andrea --- bio-cgroup: encode bio_cgroup_id in page_cgroup->flags Encode the bio_cgroup_id into the flags argument of page_cgroup as suggested by Kamezawa. Lower 16-bits of the flags attribute are used for the actual page_cgroup flags. The rest is reserved to store the bio-cgroup id. This allows to save 4 bytes (in 32-bit architectures) or 8 bytes (in 64-bit) for each page_cgroup element. Signed-off-by: Andrea Righi --- include/linux/biotrack.h | 2 +- include/linux/page_cgroup.h | 24 +++++++++++++++++++++--- mm/biotrack.c | 26 ++++++++++++-------------- 3 files changed, 34 insertions(+), 18 deletions(-) diff --git a/include/linux/biotrack.h b/include/linux/biotrack.h index 25b8810..4bd0242 100644 --- a/include/linux/biotrack.h +++ b/include/linux/biotrack.h @@ -28,7 +28,7 @@ struct bio_cgroup { static inline void __init_bio_page_cgroup(struct page_cgroup *pc) { - pc->bio_cgroup_id = 0; + page_cgroup_set_bio_id(pc, 0); } extern struct cgroup *get_cgroup_from_page(struct page *page); diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h index 00a49c5..af780a4 100644 --- a/include/linux/page_cgroup.h +++ b/include/linux/page_cgroup.h @@ -16,12 +16,30 @@ struct page_cgroup { #ifdef CONFIG_CGROUP_MEM_RES_CTLR struct mem_cgroup *mem_cgroup; #endif -#ifdef CONFIG_CGROUP_BIO - int bio_cgroup_id; -#endif struct list_head lru; /* per cgroup LRU list */ }; +#ifdef CONFIG_CGROUP_BIO +/* + * use lower 16 bits for flags and reserve the rest for the bio-cgroup id + */ +#define BIO_CGROUP_ID_SHIFT (16) +#define BIO_CGROUP_ID_BITS (8 * sizeof(unsigned long) - BIO_CGROUP_ID_SHIFT) + +static inline unsigned long page_cgroup_get_bio_id(struct page_cgroup *pc) +{ + return pc->flags >> BIO_CGROUP_ID_SHIFT; +} + +static inline void page_cgroup_set_bio_id(struct page_cgroup *pc, + unsigned long id) +{ + WARN_ON(id >= (1UL << BIO_CGROUP_ID_BITS)); + pc->flags &= (1UL << BIO_CGROUP_ID_SHIFT) - 1; + pc->flags |= (unsigned long)(id << BIO_CGROUP_ID_SHIFT); +} +#endif + void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat); void __init page_cgroup_init(void); struct page_cgroup *lookup_page_cgroup(struct page *page); diff --git a/mm/biotrack.c b/mm/biotrack.c index 431056c..4cca3bf 100644 --- a/mm/biotrack.c +++ b/mm/biotrack.c @@ -74,7 +74,7 @@ void bio_cgroup_set_owner(struct page *page, struct mm_struct *mm) struct bio_cgroup *biog; struct page_cgroup *pc; - WARN_ON_ONCE(test_bit(PG_locked, &page->flags)); + WARN_ON_ONCE(!test_bit(PG_locked, &page->flags)); if (bio_cgroup_disabled()) return; @@ -82,7 +82,7 @@ void bio_cgroup_set_owner(struct page *page, struct mm_struct *mm) if (unlikely(!pc)) return; - pc->bio_cgroup_id = 0; /* 0: default bio_cgroup id */ + __init_bio_page_cgroup(pc); if (!mm) return; /* @@ -95,11 +95,11 @@ void bio_cgroup_set_owner(struct page *page, struct mm_struct *mm) goto out; /* * css_get(&bio->css) isn't called to increment the reference - * count of this bio_cgroup "biog" so pc->bio_cgroup_id might turn - * invalid even if this page is still active. - * This approach is chosen to minimize the overhead. + * count of this bio_cgroup "biog" so the bio-cgroup id might turn + * invalid even if this page is still active. This approach is chosen + * to minimize the overhead. */ - pc->bio_cgroup_id = biog->id; + page_cgroup_set_bio_id(pc, biog->id); out: rcu_read_unlock(); } @@ -112,7 +112,7 @@ void bio_cgroup_reset_owner(struct page *page, struct mm_struct *mm) /* * A little trick: * Just call bio_cgroup_set_owner() for pages which are already - * active since the bio_cgroup_id member of page_cgroup can be + * active since the bio-cgroup id member of page_cgroup can be * updated without any locks. This is because an integer type of * variable can be set a new value at once on modern cpus. */ @@ -148,12 +148,10 @@ void bio_cgroup_copy_owner(struct page *npage, struct page *opage) opc = lookup_page_cgroup(opage); if (unlikely(!opc)) return; - /* - * Do this without any locks. The reason is the same as - * bio_cgroup_reset_owner(). + * XXX: is it safe to do this without locking? */ - npc->bio_cgroup_id = opc->bio_cgroup_id; + page_cgroup_set_bio_id(npc, page_cgroup_get_bio_id(opc)); } /* Create a new bio-cgroup. */ @@ -250,7 +248,7 @@ struct cgroup *get_cgroup_from_page(struct page *page) if (!pc) return NULL; lock_page_cgroup(pc); - biog = find_bio_cgroup(pc->bio_cgroup_id); + biog = find_bio_cgroup(page_cgroup_get_bio_id(pc)); if (biog) { css_get(&biog->css); cgrp = biog->css.cgroup; @@ -268,7 +266,7 @@ void put_cgroup_from_page(struct page *page) if (!pc) return; lock_page_cgroup(pc); - biog = find_bio_cgroup(pc->bio_cgroup_id); + biog = find_bio_cgroup(page_cgroup_get_bio_id(pc)); if (biog) css_put(&biog->css); unlock_page_cgroup(pc); @@ -283,7 +281,7 @@ int get_bio_cgroup_id(struct bio *bio) pc = lookup_page_cgroup(page); if (pc) - id = pc->bio_cgroup_id; + id = page_cgroup_get_bio_id(pc); return id; } EXPORT_SYMBOL(get_bio_cgroup_id);