From patchwork Thu Dec 10 17:30:37 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikulas Patocka X-Patchwork-Id: 7820851 Return-Path: X-Original-To: patchwork-linux-block@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 26FA9BEEE5 for ; Thu, 10 Dec 2015 17:33:56 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 53E6420524 for ; Thu, 10 Dec 2015 17:33:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F44F20592 for ; Thu, 10 Dec 2015 17:33:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755085AbbLJRal (ORCPT ); Thu, 10 Dec 2015 12:30:41 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45617 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754378AbbLJRai (ORCPT ); Thu, 10 Dec 2015 12:30:38 -0500 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (Postfix) with ESMTPS id 6239A36D06D; Thu, 10 Dec 2015 17:30:38 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (file01.intranet.prod.int.rdu2.redhat.com [10.11.5.7]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id tBAHUbPm009243 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 10 Dec 2015 12:30:38 -0500 Received: from file01.intranet.prod.int.rdu2.redhat.com (localhost [127.0.0.1]) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4) with ESMTP id tBAHUbcn001145; Thu, 10 Dec 2015 12:30:37 -0500 Received: from localhost (mpatocka@localhost) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4/Submit) with ESMTP id tBAHUbUj001141; Thu, 10 Dec 2015 12:30:37 -0500 X-Authentication-Warning: file01.intranet.prod.int.rdu2.redhat.com: mpatocka owned process doing -bs Date: Thu, 10 Dec 2015 12:30:37 -0500 (EST) From: Mikulas Patocka X-X-Sender: mpatocka@file01.intranet.prod.int.rdu2.redhat.com To: "James E.J. Bottomley" , "Martin K. Petersen" , Jens Axboe , Mike Snitzer , Jonathan Brassow cc: dm-devel@redhat.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org Subject: [PATCH 7/15] scsi xcopy: keep cache of failures In-Reply-To: Message-ID: References: User-Agent: Alpine 2.02 (LRH 1266 2009-07-14) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If xcopy between two devices fails, it is pointless to send more xcopy command between there two devices because they take time and they will likely also fail. This patch keeps a cache of (source_device,destination_device) pairs where copying failed and makes sure that no xcopy command is sooner than 30 seconds after the last failure. Signed-off-by: Mikulas Patocka --- drivers/scsi/sd.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Index: linux-4.4-rc4/drivers/scsi/sd.c =================================================================== --- linux-4.4-rc4.orig/drivers/scsi/sd.c 2015-12-07 16:59:09.000000000 +0100 +++ linux-4.4-rc4/drivers/scsi/sd.c 2015-12-07 16:59:12.000000000 +0100 @@ -939,6 +939,26 @@ static void sd_config_copy(struct scsi_d (logical_block_size >> 9)); } +#define SD_COPY_DISABLED_CACHE_TIME (HZ * 30) +#define SD_COPY_DISABLED_CACHE_HASH_BITS 6 +#define SD_COPY_DISABLED_CACHE_HASH (1 << SD_COPY_DISABLED_CACHE_HASH_BITS) + +struct sd_copy_disabled_cache_entry { + struct scsi_device *src; + struct scsi_device *dst; + unsigned long jiffies; +}; + +static struct sd_copy_disabled_cache_entry sd_copy_disabled_cache[SD_COPY_DISABLED_CACHE_HASH]; + +static struct sd_copy_disabled_cache_entry *sd_copy_disabled_cache_hash( + struct scsi_device *src, struct scsi_device *dst) +{ + return &sd_copy_disabled_cache[ + hash_long((unsigned long)src + ((unsigned long)dst >> 1), SD_COPY_DISABLED_CACHE_HASH_BITS) + ]; +} + static int sd_setup_copy_cmnd(struct scsi_cmnd *cmd) { struct request *rq = cmd->request; @@ -951,6 +971,7 @@ static int sd_setup_copy_cmnd(struct scs struct bio *bio = rq->bio; struct page *page; unsigned char *buf; + struct sd_copy_disabled_cache_entry *e; dst_sdp = scsi_disk(rq->rq_disk)->device; dst_queue = rq->rq_disk->queue; @@ -970,6 +991,12 @@ static int sd_setup_copy_cmnd(struct scs if (src_sdp->sector_size != dst_sdp->sector_size) return BLKPREP_KILL; + /* The copy failed in the past, so do not retry it for some time */ + e = sd_copy_disabled_cache_hash(src_sdp, dst_sdp); + if (unlikely(jiffies - ACCESS_ONCE(e->jiffies) < SD_COPY_DISABLED_CACHE_TIME) && + likely(ACCESS_ONCE(e->src) == src_sdp) && likely(ACCESS_ONCE(e->dst) == dst_sdp)) + return BLKPREP_KILL; + dst_lba = blk_rq_pos(rq) >> (ilog2(dst_sdp->sector_size) - 9); src_lba = bio->bi_copy->pair[0]->bi_iter.bi_sector >> (ilog2(src_sdp->sector_size) - 9); nr_blocks = blk_rq_sectors(rq) >> (ilog2(dst_sdp->sector_size) - 9); @@ -2003,6 +2030,16 @@ static int sd_done(struct scsi_cmnd *SCp */ case EXTENDED_COPY: if ((SCpnt->cmnd[1] & 0x1f) == 0) { + struct sd_copy_disabled_cache_entry *e; + struct scsi_device *src_sdp, *dst_sdp; + + dst_sdp = sdkp->device; + src_sdp = scsi_disk(req->bio->bi_copy->pair[0]->bi_bdev->bd_disk)->device; + e = sd_copy_disabled_cache_hash(src_sdp, dst_sdp); + ACCESS_ONCE(e->src) = src_sdp; + ACCESS_ONCE(e->dst) = dst_sdp; + ACCESS_ONCE(e->jiffies) = jiffies; + good_bytes = 0; req->__data_len = blk_rq_bytes(req); req->cmd_flags |= REQ_QUIET;