Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753936Ab0FXAaT (ORCPT ); Wed, 23 Jun 2010 20:30:19 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:36572 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753006Ab0FXAaR (ORCPT ); Wed, 23 Jun 2010 20:30:17 -0400 From: Tao Ma To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, stable@kernel.org, hch@lst.de, axboe@kernel.dk, linux-fsdevel@vger.kernel.org, Tao Ma Subject: [PATCH v2] block: Don't count_vm_events for discard bio in submit_bio. Date: Thu, 24 Jun 2010 08:28:15 +0800 Message-Id: <1277339295-6524-1-git-send-email-tao.ma@oracle.com> X-Mailer: git-send-email 1.7.0.4 In-Reply-To: <20100623124046.4dec96d1.akpm@linux-foundation.org> References: <20100623124046.4dec96d1.akpm@linux-foundation.org> X-Auth-Type: Internal IP X-Source-IP: acsinet15.oracle.com [141.146.126.227] X-CT-RefId: str=0001.0A090202.4C22A6D9.0146:SCFMA922111,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2018 Lines: 55 Hi Andrew, > Yes, that's a buglet. > > Note that Christoph's "[PATCH, RFC] block: don't allocate a payload for > discard request" will fix it in a better way. That patch is in > linux-next now, but I expect it will be taken out again (quickly, > please) because Mike has found a number of problems with it. ok, I haven't noticed that. thanks for the info. > > Your patch looks like a decent temporary fix for mainline, and a > permanent one for -stable. I am sorry, but I made a mistake. BIO_RW_DISCARD is a enum for bit offset. So the right check should be rw & (1 << BIO_RW_DISCARD). I have regenerated the patch. Sorry for the inconvenience. Regards, Tao >From 060630d842a987a518c648ff65160639100c9a1b Mon Sep 17 00:00:00 2001 From: Tao Ma Date: Thu, 24 Jun 2010 07:43:57 +0800 Subject: [PATCH v2] block: Don't count_vm_events for discard bio in submit_bio. In submit_bio, we count vm events by check READ/WRITE. But actually DISCARD_NOBARRIER also has the WRITE flag set. It looks as if in blkdev_issue_discard, we also add a page as the payload and the bio_has_data check isn't enough. So add another check for discard bio. Signed-off-by: Tao Ma --- block/blk-core.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index f84cce4..26aa542 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1586,7 +1586,7 @@ void submit_bio(int rw, struct bio *bio) * If it's a regular read/write or a barrier with data attached, * go through the normal accounting stuff before submission. */ - if (bio_has_data(bio)) { + if (bio_has_data(bio) && !(rw & (1 << BIO_RW_DISCARD))) { if (rw & WRITE) { count_vm_events(PGPGOUT, count); } else { -- 1.5.5 -- 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/