From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754706AbbFPNTY (ORCPT ); Tue, 16 Jun 2015 09:19:24 -0400 Received: from mail-pd0-f182.google.com ([209.85.192.182]:36728 "EHLO mail-pd0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756221AbbFPNTP (ORCPT ); Tue, 16 Jun 2015 09:19:15 -0400 Date: Tue, 16 Jun 2015 22:19:03 +0900 From: Minchan Kim To: Sergey Senozhatsky Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky Subject: Re: [RFC][PATCHv2 2/8] zsmalloc: partial page ordering within a fullness_list Message-ID: <20150616131903.GA31387@blaptop> References: <1433505838-23058-1-git-send-email-sergey.senozhatsky@gmail.com> <1433505838-23058-3-git-send-email-sergey.senozhatsky@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1433505838-23058-3-git-send-email-sergey.senozhatsky@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Sergey, On Fri, Jun 05, 2015 at 09:03:52PM +0900, Sergey Senozhatsky wrote: > We want to see more ZS_FULL pages and less ZS_ALMOST_{FULL, EMPTY} > pages. Put a page with higher ->inuse count first within its > ->fullness_list, which will give us better chances to fill up this > page with new objects (find_get_zspage() return ->fullness_list head > for new object allocation), so some zspages will become > ZS_ALMOST_FULL/ZS_FULL quicker. > > It performs a trivial and cheap ->inuse compare which does not slow > down zsmalloc, and in the worst case it keeps the list pages not in > any particular order, just like we do it now. Fair enough. I think it would be better with small cost and it matches current zsmalloc design which allocates a object from ALMOST_FULL zspage first to reduce memory footprint. Although we uses page->lru to link zspages, it's not lru order so I like your idea. One think I want to say is it doesn't need to be part of this patchset. I hope you gives some data to prove gain and includes it in changelog and resubmit, please. > > A more expensive solution could sort fullness_list by ->inuse count. > > Signed-off-by: Sergey Senozhatsky > --- > mm/zsmalloc.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index ce3310c..cd37bda 100644 > --- a/mm/zsmalloc.c > +++ b/mm/zsmalloc.c > @@ -658,8 +658,16 @@ static void insert_zspage(struct page *page, struct size_class *class, > return; > > head = &class->fullness_list[fullness]; > - if (*head) > - list_add_tail(&page->lru, &(*head)->lru); > + if (*head) { > + /* > + * We want to see more ZS_FULL pages and less almost > + * empty/full. Put pages with higher ->inuse first. > + */ > + if (page->inuse < (*head)->inuse) > + list_add_tail(&page->lru, &(*head)->lru); > + else > + list_add(&page->lru, &(*head)->lru); > + } > > *head = page; > zs_stat_inc(class, fullness == ZS_ALMOST_EMPTY ? > -- > 2.4.2.387.gf86f31a > -- Kind regards, Minchan Kim From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f53.google.com (mail-pa0-f53.google.com [209.85.220.53]) by kanga.kvack.org (Postfix) with ESMTP id 3C9526B006E for ; Tue, 16 Jun 2015 09:19:17 -0400 (EDT) Received: by pabqy3 with SMTP id qy3so12723976pab.3 for ; Tue, 16 Jun 2015 06:19:17 -0700 (PDT) Received: from mail-pd0-x236.google.com (mail-pd0-x236.google.com. [2607:f8b0:400e:c02::236]) by mx.google.com with ESMTPS id hg5si1407108pac.34.2015.06.16.06.19.15 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 16 Jun 2015 06:19:15 -0700 (PDT) Received: by pdbki1 with SMTP id ki1so14390303pdb.1 for ; Tue, 16 Jun 2015 06:19:15 -0700 (PDT) Date: Tue, 16 Jun 2015 22:19:03 +0900 From: Minchan Kim Subject: Re: [RFC][PATCHv2 2/8] zsmalloc: partial page ordering within a fullness_list Message-ID: <20150616131903.GA31387@blaptop> References: <1433505838-23058-1-git-send-email-sergey.senozhatsky@gmail.com> <1433505838-23058-3-git-send-email-sergey.senozhatsky@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1433505838-23058-3-git-send-email-sergey.senozhatsky@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Sergey Senozhatsky Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky Hello Sergey, On Fri, Jun 05, 2015 at 09:03:52PM +0900, Sergey Senozhatsky wrote: > We want to see more ZS_FULL pages and less ZS_ALMOST_{FULL, EMPTY} > pages. Put a page with higher ->inuse count first within its > ->fullness_list, which will give us better chances to fill up this > page with new objects (find_get_zspage() return ->fullness_list head > for new object allocation), so some zspages will become > ZS_ALMOST_FULL/ZS_FULL quicker. > > It performs a trivial and cheap ->inuse compare which does not slow > down zsmalloc, and in the worst case it keeps the list pages not in > any particular order, just like we do it now. Fair enough. I think it would be better with small cost and it matches current zsmalloc design which allocates a object from ALMOST_FULL zspage first to reduce memory footprint. Although we uses page->lru to link zspages, it's not lru order so I like your idea. One think I want to say is it doesn't need to be part of this patchset. I hope you gives some data to prove gain and includes it in changelog and resubmit, please. > > A more expensive solution could sort fullness_list by ->inuse count. > > Signed-off-by: Sergey Senozhatsky > --- > mm/zsmalloc.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index ce3310c..cd37bda 100644 > --- a/mm/zsmalloc.c > +++ b/mm/zsmalloc.c > @@ -658,8 +658,16 @@ static void insert_zspage(struct page *page, struct size_class *class, > return; > > head = &class->fullness_list[fullness]; > - if (*head) > - list_add_tail(&page->lru, &(*head)->lru); > + if (*head) { > + /* > + * We want to see more ZS_FULL pages and less almost > + * empty/full. Put pages with higher ->inuse first. > + */ > + if (page->inuse < (*head)->inuse) > + list_add_tail(&page->lru, &(*head)->lru); > + else > + list_add(&page->lru, &(*head)->lru); > + } > > *head = page; > zs_stat_inc(class, fullness == ZS_ALMOST_EMPTY ? > -- > 2.4.2.387.gf86f31a > -- 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