From mboxrd@z Thu Jan 1 00:00:00 1970 From: Namjae Jeon Subject: Re: [PATCH 4/4] f2fs: add blk plugging support in f2fs Date: Mon, 14 Jan 2013 20:10:01 +0900 Message-ID: References: <1357969323-9396-1-git-send-email-linkinjeon@gmail.com> <1358128249.23942.6.camel@kjgkr> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, Namjae Jeon , Amit Sahrawat To: jaegeuk.kim@samsung.com Return-path: Received: from mail-qa0-f44.google.com ([209.85.216.44]:42451 "EHLO mail-qa0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751384Ab3ANLKD convert rfc822-to-8bit (ORCPT ); Mon, 14 Jan 2013 06:10:03 -0500 In-Reply-To: <1358128249.23942.6.camel@kjgkr> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 2013/1/14, Jaegeuk Kim : > 2013-01-12 (=ED=86=A0), 14:42 +0900, Namjae Jeon: >> From: Namjae Jeon >> >> With f2fs having different writepages support for data, node and >> metapages. >> It will not be covered under the generic blk plug support. > > Could you show any improvement points with this patch? > > Currently, there is no reason to use blk plugging, since f2fs itself > gathers bios and then submit one big bio. > > Thanks, Hi Jaegeuk, There is no performance difference after introducing the block plugging in F2FS. We introduced this to reduced block lock contention for f2fs also. =46or every BIO request queuing part to the request queue: it needs to acquire lock-> spin_lock_irq(q->queue_lock); Even though the F2FS - already is handling the requests part very well. But still we can make use of blk_plug to reduce the block lock contention. When we introduce block plugging to F2FS part - all the requests will first be maintained on TASK basis and then pushed to the request queue. So, we do not have contention for the =E2=80=9Cqueue lock=E2=80=9D= =2E If we consider the normal data write path: initial block plug is already taken care by generic write_pages(for f2fs readpages block plug is already taken care by default path of: read_pages()->mpage_readpages())), but we can optimize this write path also as we shared the in patch. Similarly, we introduced block plug for the node_page and meta_pages. Please share your opinion on this. Thanks! > > -- > Jaegeuk Kim > Samsung > -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html