Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757064Ab1CIObM (ORCPT ); Wed, 9 Mar 2011 09:31:12 -0500 Received: from mx1.redhat.com ([209.132.183.28]:25996 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757032Ab1CIObK (ORCPT ); Wed, 9 Mar 2011 09:31:10 -0500 From: Jeff Moyer To: Tao Ma Cc: linux-kernel@vger.kernel.org, Jens Axboe Subject: Re: [PATCH] blktrace: Use rq->cmd_flags directly in blk_add_trace_rq. References: <1299219358-17507-1-git-send-email-tm@tao.ma> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 X-PCLoadLetter: What the f**k does that mean? Date: Wed, 09 Mar 2011 09:31:05 -0500 In-Reply-To: <1299219358-17507-1-git-send-email-tm@tao.ma> (Tao Ma's message of "Fri, 4 Mar 2011 14:15:58 +0800") Message-ID: User-Agent: Gnus/5.110011 (No Gnus v0.11) Emacs/23.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2990 Lines: 78 Tao Ma writes: > From: Tao Ma > > In blk_add_trace_rq, we only chose the minor 2 bits from > request's cmd_flags and did some check for discard. > so most of other flags(e.g, REQ_SYNC) are missing. > > For example, with a sync write after blkparse we get: > 8,16 1 1 0.001776503 7509 A WS 1349632 + 1024 <- (8,17) 1347584 > 8,16 1 2 0.001776813 7509 Q WS 1349632 + 1024 [dd] > 8,16 1 3 0.001780395 7509 G WS 1349632 + 1024 [dd] > 8,16 1 5 0.001783186 7509 I W 1349632 + 1024 [dd] > 8,16 1 11 0.001816987 7509 D W 1349632 + 1024 [dd] > 8,16 0 2 0.006218192 0 C W 1349632 + 1024 [0] > > Since now we have integrated the flags of both bio and request, > it is safe to pass rq->cmd_flags directly to __blk_add_trace. > > With this patch, after a sync write we get: > 8,16 1 1 0.001776900 5425 A WS 1189888 + 1024 <- (8,17) 1187840 > 8,16 1 2 0.001777179 5425 Q WS 1189888 + 1024 [dd] > 8,16 1 3 0.001780797 5425 G WS 1189888 + 1024 [dd] > 8,16 1 5 0.001783402 5425 I WS 1189888 + 1024 [dd] > 8,16 1 11 0.001817468 5425 D WS 1189888 + 1024 [dd] > 8,16 0 2 0.005640709 0 C WS 1189888 + 1024 [0] > > Cc: Jens Axboe > Signed-off-by: Tao Ma > --- > kernel/trace/blktrace.c | 15 ++++----------- > 1 files changed, 4 insertions(+), 11 deletions(-) > > diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c > index cbafed7..7aa40f8 100644 > --- a/kernel/trace/blktrace.c > +++ b/kernel/trace/blktrace.c > @@ -703,28 +703,21 @@ void blk_trace_shutdown(struct request_queue *q) > * > **/ > static void blk_add_trace_rq(struct request_queue *q, struct request *rq, > - u32 what) > + u32 what) > { > struct blk_trace *bt = q->blk_trace; > - int rw = rq->cmd_flags & 0x03; > > if (likely(!bt)) > return; > > - if (rq->cmd_flags & REQ_DISCARD) > - rw |= REQ_DISCARD; > - > - if (rq->cmd_flags & REQ_SECURE) > - rw |= REQ_SECURE; > - > if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { > what |= BLK_TC_ACT(BLK_TC_PC); > - __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw, > + __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags, > what, rq->errors, rq->cmd_len, rq->cmd); > } else { > what |= BLK_TC_ACT(BLK_TC_FS); > - __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw, > - what, rq->errors, 0, NULL); > + __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), > + rq->cmd_flags, what, rq->errors, 0, NULL); > } > } Looks like a fine cleanup to me. Acked-by: Jeff Moyer -- 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/