From patchwork Wed Mar 18 08:38:16 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kiyoshi Ueda X-Patchwork-Id: 12778 X-Patchwork-Delegate: agk@redhat.com Received: from hormel.redhat.com (hormel1.redhat.com [209.132.177.33]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n2I8cr3a022594 for ; Wed, 18 Mar 2009 08:38:53 GMT Received: from listman.util.phx.redhat.com (listman.util.phx.redhat.com [10.8.4.110]) by hormel.redhat.com (Postfix) with ESMTP id E2FC4618AE4; Wed, 18 Mar 2009 04:38:52 -0400 (EDT) Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com [172.16.52.254]) by listman.util.phx.redhat.com (8.13.1/8.13.1) with ESMTP id n2I8co8L003463 for ; Wed, 18 Mar 2009 04:38:50 -0400 Received: from mx3.redhat.com (mx3.redhat.com [172.16.48.32]) by int-mx1.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n2I8cpRd014073; Wed, 18 Mar 2009 04:38:51 -0400 Received: from tyo201.gate.nec.co.jp (TYO201.gate.nec.co.jp [202.32.8.193]) by mx3.redhat.com (8.13.8/8.13.8) with ESMTP id n2I8cN5s023820; Wed, 18 Mar 2009 04:38:23 -0400 Received: from mailgate3.nec.co.jp ([10.7.69.192]) by tyo201.gate.nec.co.jp (8.13.8/8.13.4) with ESMTP id n2I8cHIB029648; Wed, 18 Mar 2009 17:38:17 +0900 (JST) Received: (from root@localhost) by mailgate3.nec.co.jp (8.11.7/3.7W-MAILGATE-NEC) id n2I8cHg19931; Wed, 18 Mar 2009 17:38:17 +0900 (JST) Received: from mailsv.linux.bs1.fc.nec.co.jp (mailsv.linux.bs1.fc.nec.co.jp [10.34.125.2]) by mailsv4.nec.co.jp (8.13.8/8.13.4) with ESMTP id n2I8cGAJ028979; Wed, 18 Mar 2009 17:38:16 +0900 (JST) Received: from elcondor.linux.bs1.fc.nec.co.jp (elcondor.linux.bs1.fc.nec.co.jp [10.34.125.195]) by mailsv.linux.bs1.fc.nec.co.jp (Postfix) with ESMTP id A010DE482A8; Wed, 18 Mar 2009 17:38:16 +0900 (JST) Message-ID: <49C0B2F8.6080507@ct.jp.nec.com> Date: Wed, 18 Mar 2009 17:38:16 +0900 From: Kiyoshi Ueda User-Agent: Thunderbird 2.0.0.19 (X11/20090105) MIME-Version: 1.0 To: Alasdair Kergon References: <49C0B222.9010600@ct.jp.nec.com> In-Reply-To: <49C0B222.9010600@ct.jp.nec.com> X-RedHat-Spam-Score: 0 X-Scanned-By: MIMEDefang 2.58 on 172.16.52.254 X-Scanned-By: MIMEDefang 2.63 on 172.16.48.32 X-loop: dm-devel@redhat.com Cc: device-mapper development , stefan.bader@canonical.com Subject: [dm-devel] [PATCH 1/3] dm-mpath: interface change for dynamic load balancers X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.5 Precedence: junk Reply-To: device-mapper development List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com This patch changes the dm path selector interface for dynamic load balancers: o adding a new hook, start_io() o adding 'nr_bytes' parameter to select_path()/start_io()/end_io() to pass the size of the I/O start_io() is called when a target driver actually submits I/O to the selected path. Path selectors can use it to start accounting of the I/O. (e.g. counting the number of in-flight I/Os.) The start_io hook is based on the patch posted by Stefan Bader: https://www.redhat.com/archives/dm-devel/2005-October/msg00050.html nr_bytes, the size of the I/O, is used by path selectors for size-based decision. dm-service-time uses it to estimate service time, for example. (Added the nr_bytes member to dm_mpath_io instead of using existing details.bi_size, since request-based dm patch deletes it.) Signed-off-by: Stefan Bader Signed-off-by: Kiyoshi Ueda Signed-off-by: Jun'ichi Nomura Cc: Vijayakumar Balasubramanian Cc: Alasdair G Kergon --- drivers/md/dm-mpath.c | 28 ++++++++++++++++++---------- drivers/md/dm-path-selector.h | 8 ++++++-- drivers/md/dm-round-robin.c | 2 +- 3 files changed, 25 insertions(+), 13 deletions(-) -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel Index: 2.6.29-rc8/drivers/md/dm-mpath.c =================================================================== --- 2.6.29-rc8.orig/drivers/md/dm-mpath.c +++ 2.6.29-rc8/drivers/md/dm-mpath.c @@ -103,6 +103,7 @@ struct multipath { struct dm_mpath_io { struct pgpath *pgpath; struct dm_bio_details details; + size_t nr_bytes; }; typedef int (*action_fn) (struct pgpath *pgpath); @@ -251,11 +252,12 @@ static void __switch_pg(struct multipath m->pg_init_count = 0; } -static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg) +static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg, + size_t nr_bytes) { struct dm_path *path; - path = pg->ps.type->select_path(&pg->ps, &m->repeat_count); + path = pg->ps.type->select_path(&pg->ps, &m->repeat_count, nr_bytes); if (!path) return -ENXIO; @@ -267,7 +269,7 @@ static int __choose_path_in_pg(struct mu return 0; } -static void __choose_pgpath(struct multipath *m) +static void __choose_pgpath(struct multipath *m, size_t nr_bytes) { struct priority_group *pg; unsigned bypassed = 1; @@ -279,12 +281,12 @@ static void __choose_pgpath(struct multi if (m->next_pg) { pg = m->next_pg; m->next_pg = NULL; - if (!__choose_path_in_pg(m, pg)) + if (!__choose_path_in_pg(m, pg, nr_bytes)) return; } /* Don't change PG until it has no remaining paths */ - if (m->current_pg && !__choose_path_in_pg(m, m->current_pg)) + if (m->current_pg && !__choose_path_in_pg(m, m->current_pg, nr_bytes)) return; /* @@ -296,7 +298,7 @@ static void __choose_pgpath(struct multi list_for_each_entry(pg, &m->priority_groups, list) { if (pg->bypassed == bypassed) continue; - if (!__choose_path_in_pg(m, pg)) + if (!__choose_path_in_pg(m, pg, nr_bytes)) return; } } while (bypassed--); @@ -327,6 +329,7 @@ static int map_io(struct multipath *m, s struct dm_mpath_io *mpio, unsigned was_queued) { int r = DM_MAPIO_REMAPPED; + size_t nr_bytes = bio->bi_size; unsigned long flags; struct pgpath *pgpath; @@ -335,7 +338,7 @@ static int map_io(struct multipath *m, s /* Do we need to select a new pgpath? */ if (!m->current_pgpath || (!m->queue_io && (m->repeat_count && --m->repeat_count == 0))) - __choose_pgpath(m); + __choose_pgpath(m, nr_bytes); pgpath = m->current_pgpath; @@ -360,6 +363,11 @@ static int map_io(struct multipath *m, s r = -EIO; /* Failed */ mpio->pgpath = pgpath; + mpio->nr_bytes = nr_bytes; + + if (r == DM_MAPIO_REMAPPED && pgpath->pg->ps.type->start_io) + pgpath->pg->ps.type->start_io(&pgpath->pg->ps, &pgpath->path, + nr_bytes); spin_unlock_irqrestore(&m->lock, flags); @@ -438,7 +446,7 @@ static void process_queued_ios(struct wo goto out; if (!m->current_pgpath) - __choose_pgpath(m); + __choose_pgpath(m, 0); pgpath = m->current_pgpath; @@ -1196,7 +1204,7 @@ static int multipath_end_io(struct dm_ta if (pgpath) { ps = &pgpath->pg->ps; if (ps->type->end_io) - ps->type->end_io(ps, &pgpath->path); + ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); } if (r != DM_ENDIO_INCOMPLETE) mempool_free(mpio, m->mpio_pool); @@ -1412,7 +1420,7 @@ static int multipath_ioctl(struct dm_tar spin_lock_irqsave(&m->lock, flags); if (!m->current_pgpath) - __choose_pgpath(m); + __choose_pgpath(m, 0); if (m->current_pgpath) { bdev = m->current_pgpath->path.dev->bdev; Index: 2.6.29-rc8/drivers/md/dm-path-selector.h =================================================================== --- 2.6.29-rc8.orig/drivers/md/dm-path-selector.h +++ 2.6.29-rc8/drivers/md/dm-path-selector.h @@ -56,7 +56,8 @@ struct path_selector_type { * the path fails. */ struct dm_path *(*select_path) (struct path_selector *ps, - unsigned *repeat_count); + unsigned *repeat_count, + size_t nr_bytes); /* * Notify the selector that a path has failed. @@ -75,7 +76,10 @@ struct path_selector_type { int (*status) (struct path_selector *ps, struct dm_path *path, status_type_t type, char *result, unsigned int maxlen); - int (*end_io) (struct path_selector *ps, struct dm_path *path); + int (*start_io) (struct path_selector *ps, struct dm_path *path, + size_t nr_bytes); + int (*end_io) (struct path_selector *ps, struct dm_path *path, + size_t nr_bytes); }; /* Register a path selector */ Index: 2.6.29-rc8/drivers/md/dm-round-robin.c =================================================================== --- 2.6.29-rc8.orig/drivers/md/dm-round-robin.c +++ 2.6.29-rc8/drivers/md/dm-round-robin.c @@ -161,7 +161,7 @@ static int rr_reinstate_path(struct path } static struct dm_path *rr_select_path(struct path_selector *ps, - unsigned *repeat_count) + unsigned *repeat_count, size_t nr_bytes) { struct selector *s = (struct selector *) ps->context; struct path_info *pi = NULL;