From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Layton Subject: Re: [PATCH v6 4/7] libceph: add an epoch_barrier field to struct ceph_osd_client Date: Wed, 05 Apr 2017 09:29:39 -0400 Message-ID: <1491398979.18658.3.camel@redhat.com> References: <20170330180546.11021-1-jlayton@redhat.com> <20170330180707.11137-1-jlayton@redhat.com> <20170330180707.11137-4-jlayton@redhat.com> <1491323678.309.3.camel@redhat.com> <1491340330.11822.3.camel@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: Received: from mail-qt0-f169.google.com ([209.85.216.169]:35039 "EHLO mail-qt0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932130AbdDEN3n (ORCPT ); Wed, 5 Apr 2017 09:29:43 -0400 Received: by mail-qt0-f169.google.com with SMTP id x35so10213842qtc.2 for ; Wed, 05 Apr 2017 06:29:43 -0700 (PDT) In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Ilya Dryomov Cc: "Yan, Zheng" , Sage Weil , John Spray , Ceph Development On Wed, 2017-04-05 at 11:22 +0200, Ilya Dryomov wrote: > On Tue, Apr 4, 2017 at 11:12 PM, Jeff Layton wrote: > > On Tue, 2017-04-04 at 21:47 +0200, Ilya Dryomov wrote: > > > On Tue, Apr 4, 2017 at 6:34 PM, Jeff Layton wrote: > > > > On Tue, 2017-04-04 at 17:00 +0200, Ilya Dryomov wrote: > > > > > On Thu, Mar 30, 2017 at 8:07 PM, Jeff Layton wrote: > > > > > > Cephfs can get cap update requests that contain a new epoch barrier in > > > > > > them. When that happens we want to pause all OSD traffic until the right > > > > > > map epoch arrives. > > > > > > > > > > > > Add an epoch_barrier field to ceph_osd_client that is protected by the > > > > > > osdc->lock rwsem. When the barrier is set, and the current OSD map > > > > > > epoch is below that, pause the request target when submitting the > > > > > > request or when revisiting it. Add a way for upper layers (cephfs) > > > > > > to update the epoch_barrier as well. > > > > > > > > > > > > If we get a new map, compare the new epoch against the barrier before > > > > > > kicking requests and request another map if the map epoch is still lower > > > > > > than the one we want. > > > > > > > > > > > > If we get a map with a full pool, or at quota condition, then set the > > > > > > barrier to the current epoch value. > > > > > > > > > > > > Reviewed-by: "Yan, Zheng” > > > > > > Signed-off-by: Jeff Layton > > > > > > --- > > > > > > include/linux/ceph/osd_client.h | 2 ++ > > > > > > net/ceph/debugfs.c | 3 ++- > > > > > > net/ceph/osd_client.c | 48 +++++++++++++++++++++++++++++++++-------- > > > > > > 3 files changed, 43 insertions(+), 10 deletions(-) > > > > > > > > > > > > diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h > > > > > > index 8cf644197b1a..85650b415e73 100644 > > > > > > --- a/include/linux/ceph/osd_client.h > > > > > > +++ b/include/linux/ceph/osd_client.h > > > > > > @@ -267,6 +267,7 @@ struct ceph_osd_client { > > > > > > struct rb_root osds; /* osds */ > > > > > > struct list_head osd_lru; /* idle osds */ > > > > > > spinlock_t osd_lru_lock; > > > > > > + u32 epoch_barrier; > > > > > > struct ceph_osd homeless_osd; > > > > > > atomic64_t last_tid; /* tid of last request */ > > > > > > u64 last_linger_id; > > > > > > @@ -305,6 +306,7 @@ extern void ceph_osdc_handle_reply(struct ceph_osd_client *osdc, > > > > > > struct ceph_msg *msg); > > > > > > extern void ceph_osdc_handle_map(struct ceph_osd_client *osdc, > > > > > > struct ceph_msg *msg); > > > > > > +void ceph_osdc_update_epoch_barrier(struct ceph_osd_client *osdc, u32 eb); > > > > > > > > > > > > extern void osd_req_op_init(struct ceph_osd_request *osd_req, > > > > > > unsigned int which, u16 opcode, u32 flags); > > > > > > diff --git a/net/ceph/debugfs.c b/net/ceph/debugfs.c > > > > > > index d7e63a4f5578..71ba13927b3d 100644 > > > > > > --- a/net/ceph/debugfs.c > > > > > > +++ b/net/ceph/debugfs.c > > > > > > @@ -62,7 +62,8 @@ static int osdmap_show(struct seq_file *s, void *p) > > > > > > return 0; > > > > > > > > > > > > down_read(&osdc->lock); > > > > > > - seq_printf(s, "epoch %d flags 0x%x\n", map->epoch, map->flags); > > > > > > + seq_printf(s, "epoch %u barrier %u flags 0x%x\n", map->epoch, > > > > > > + osdc->epoch_barrier, map->flags); > > > > > > > > > > > > for (n = rb_first(&map->pg_pools); n; n = rb_next(n)) { > > > > > > struct ceph_pg_pool_info *pi = > > > > > > diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c > > > > > > index 4e56cd1ec265..3a94e8a1c7ff 100644 > > > > > > --- a/net/ceph/osd_client.c > > > > > > +++ b/net/ceph/osd_client.c > > > > > > @@ -1298,8 +1298,9 @@ static bool target_should_be_paused(struct ceph_osd_client *osdc, > > > > > > __pool_full(pi); > > > > > > > > > > > > WARN_ON(pi->id != t->base_oloc.pool); > > > > > > - return (t->flags & CEPH_OSD_FLAG_READ && pauserd) || > > > > > > - (t->flags & CEPH_OSD_FLAG_WRITE && pausewr); > > > > > > + return ((t->flags & CEPH_OSD_FLAG_READ) && pauserd) || > > > > > > + ((t->flags & CEPH_OSD_FLAG_WRITE) && pausewr) || > > > > > > + (osdc->osdmap->epoch < osdc->epoch_barrier); > > > > > > } > > > > > > > > > > > > enum calc_target_result { > > > > > > @@ -1609,13 +1610,15 @@ static void send_request(struct ceph_osd_request *req) > > > > > > static void maybe_request_map(struct ceph_osd_client *osdc) > > > > > > { > > > > > > bool continuous = false; > > > > > > + u32 epoch = osdc->osdmap->epoch; > > > > > > > > > > > > verify_osdc_locked(osdc); > > > > > > - WARN_ON(!osdc->osdmap->epoch); > > > > > > + WARN_ON_ONCE(epoch == 0); > > > > > > > > > > > > if (ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL) || > > > > > > ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSERD) || > > > > > > - ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSEWR)) { > > > > > > + ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSEWR) || > > > > > > + epoch < osdc->epoch_barrier) { > > > > > > dout("%s osdc %p continuous\n", __func__, osdc); > > > > > > continuous = true; > > > > > > } else { > > > > > > > > > > Looks like this hunk is smaller now, but I thought we agreed to drop it > > > > > entirely? "epoch < osdc->epoch_barrier" isn't there in Objecter. > > > > > > > > > > > > > I still think if the current map is behind the current barrier value, > > > > then you really do want to request a map. I'm not sure that the other > > > > flags will necessarily be set in that case, will they? > > > > > > We do that from ceph_osdc_handle_map(), on every new map. That should > > > be good enough -- I'm not sure if that continuous sub in FULL, PAUSERD > > > and PAUSEWR cases buys us anything at all. > > > > > > > Ahh ok, I see what you're saying now. Fair enough, we probably don't > > need a continuous sub to handle an epoch_barrier that we don't have the > > map for yet. > > > > That said...should maybe_request_map be calling ceph_monc_want_map with > > this as the epoch argument? > > > > max(epoch+1, osdc->epoch_barrier) > > > > It seems like if the barrier is more than one greater than the one we > > currently have then we should request enough to get us to the barrier. > > No. If the osdc->epoch_barrier is more than one greater, that would > request maps with epochs >= osdc->epoch_barrier, leaving the [epoch + 1, > osdc->epoch_barrier) gap. > > We are checking osdc->epoch_barrier in ceph_osdc_handle_map() on every > incoming map and requesting more maps if needed, so eventually we will > get to the barrier. > Ok, got it...does this patch look OK? --------------------------8<---------------------------------- [PATCH] libceph: add an epoch_barrier field to struct ceph_osd_client Cephfs can get cap update requests that contain a new epoch barrier in them. When that happens we want to pause all OSD traffic until the right map epoch arrives. Add an epoch_barrier field to ceph_osd_client that is protected by the osdc->lock rwsem. When the barrier is set, and the current OSD map epoch is below that, pause the request target when submitting the request or when revisiting it. Add a way for upper layers (cephfs) to update the epoch_barrier as well. If we get a new map, compare the new epoch against the barrier before kicking requests and request another map if the map epoch is still lower than the one we want. If we get a map with a full pool, or at quota condition, then set the barrier to the current epoch value. Reviewed-by: "Yan, Zheng” Signed-off-by: Jeff Layton Reviewed-by: Ilya Dryomov --- include/linux/ceph/osd_client.h | 2 ++ net/ceph/debugfs.c | 3 ++- net/ceph/osd_client.c | 50 ++++++++++++++++++++++++++++++++++------- 3 files changed, 46 insertions(+), 9 deletions(-) diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h index 8cf644197b1a..85650b415e73 100644 --- a/include/linux/ceph/osd_client.h +++ b/include/linux/ceph/osd_client.h @@ -267,6 +267,7 @@ struct ceph_osd_client { struct rb_root osds; /* osds */ struct list_head osd_lru; /* idle osds */ spinlock_t osd_lru_lock; + u32 epoch_barrier; struct ceph_osd homeless_osd; atomic64_t last_tid; /* tid of last request */ u64 last_linger_id; @@ -305,6 +306,7 @@ extern void ceph_osdc_handle_reply(struct ceph_osd_client *osdc, struct ceph_msg *msg); extern void ceph_osdc_handle_map(struct ceph_osd_client *osdc, struct ceph_msg *msg); +void ceph_osdc_update_epoch_barrier(struct ceph_osd_client *osdc, u32 eb); extern void osd_req_op_init(struct ceph_osd_request *osd_req, unsigned int which, u16 opcode, u32 flags); diff --git a/net/ceph/debugfs.c b/net/ceph/debugfs.c index d7e63a4f5578..71ba13927b3d 100644 --- a/net/ceph/debugfs.c +++ b/net/ceph/debugfs.c @@ -62,7 +62,8 @@ static int osdmap_show(struct seq_file *s, void *p) return 0; down_read(&osdc->lock); - seq_printf(s, "epoch %d flags 0x%x\n", map->epoch, map->flags); + seq_printf(s, "epoch %u barrier %u flags 0x%x\n", map->epoch, + osdc->epoch_barrier, map->flags); for (n = rb_first(&map->pg_pools); n; n = rb_next(n)) { struct ceph_pg_pool_info *pi = diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c index 55b7585ccefd..fb35adae7fbf 100644 --- a/net/ceph/osd_client.c +++ b/net/ceph/osd_client.c @@ -1298,8 +1298,9 @@ static bool target_should_be_paused(struct ceph_osd_client *osdc, __pool_full(pi); WARN_ON(pi->id != t->base_oloc.pool); - return (t->flags & CEPH_OSD_FLAG_READ && pauserd) || - (t->flags & CEPH_OSD_FLAG_WRITE && pausewr); + return ((t->flags & CEPH_OSD_FLAG_READ) && pauserd) || + ((t->flags & CEPH_OSD_FLAG_WRITE) && pausewr) || + (osdc->osdmap->epoch < osdc->epoch_barrier); } enum calc_target_result { @@ -1654,8 +1655,13 @@ static void __submit_request(struct ceph_osd_request *req, bool wrlocked) goto promote; } - if ((req->r_flags & CEPH_OSD_FLAG_WRITE) && - ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSEWR)) { + if (osdc->osdmap->epoch < osdc->epoch_barrier) { + dout("req %p epoch %u barrier %u\n", req, osdc->osdmap->epoch, + osdc->epoch_barrier); + req->r_t.paused = true; + maybe_request_map(osdc); + } else if ((req->r_flags & CEPH_OSD_FLAG_WRITE) && + ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSEWR)) { dout("req %p pausewr\n", req); req->r_t.paused = true; maybe_request_map(osdc); @@ -1809,11 +1815,14 @@ static void abort_request(struct ceph_osd_request *req, int err) /* * Drop all pending requests that are stalled waiting on a full condition to - * clear, and complete them with ENOSPC as the return code. + * clear, and complete them with ENOSPC as the return code. Set the + * osdc->epoch_barrier to the latest map epoch that we've seen if any were + * cancelled. */ static void ceph_osdc_abort_on_full(struct ceph_osd_client *osdc) { struct rb_node *n; + bool set_barrier = false; dout("enter abort_on_full\n"); @@ -1832,12 +1841,18 @@ static void ceph_osdc_abort_on_full(struct ceph_osd_client *osdc) if (req->r_abort_on_full && (ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL) || - pool_full(osdc, req->r_t.target_oloc.pool))) + pool_full(osdc, req->r_t.target_oloc.pool))) { abort_request(req, -ENOSPC); + set_barrier = true; + } } } + + /* Update the epoch barrier to current epoch if a call was aborted */ + if (set_barrier) + osdc->epoch_barrier = osdc->osdmap->epoch; out: - dout("return abort_on_full\n"); + dout("return abort_on_full barrier=%u\n", osdc->epoch_barrier); } static void check_pool_dne(struct ceph_osd_request *req) @@ -3293,7 +3308,8 @@ void ceph_osdc_handle_map(struct ceph_osd_client *osdc, struct ceph_msg *msg) pausewr = ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSEWR) || ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL) || have_pool_full(osdc); - if (was_pauserd || was_pausewr || pauserd || pausewr) + if (was_pauserd || was_pausewr || pauserd || pausewr || + osdc->osdmap->epoch < osdc->epoch_barrier) maybe_request_map(osdc); kick_requests(osdc, &need_resend, &need_resend_linger); @@ -3311,6 +3327,24 @@ void ceph_osdc_handle_map(struct ceph_osd_client *osdc, struct ceph_msg *msg) up_write(&osdc->lock); } +void ceph_osdc_update_epoch_barrier(struct ceph_osd_client *osdc, u32 eb) +{ + down_read(&osdc->lock); + if (unlikely(eb > osdc->epoch_barrier)) { + up_read(&osdc->lock); + down_write(&osdc->lock); + if (likely(eb > osdc->epoch_barrier)) { + dout("updating epoch_barrier from %u to %u\n", + osdc->epoch_barrier, eb); + osdc->epoch_barrier = eb; + } + up_write(&osdc->lock); + } else { + up_read(&osdc->lock); + } +} +EXPORT_SYMBOL(ceph_osdc_update_epoch_barrier); + /* * Resubmit requests pending on the given osd. */ -- 2.9.3