From: Mikulas Patocka <mpatocka@redhat.com> To: Michal Hocko <mhocko@kernel.org> Cc: Ondrej Kozina <okozina@redhat.com>, Jerome Marchand <jmarchan@redhat.com>, Stanislav Kozina <skozina@redhat.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com Subject: Re: System freezes after OOM Date: Thu, 14 Jul 2016 10:00:16 -0400 (EDT) [thread overview] Message-ID: <alpine.LRH.2.02.1607140952550.1102@file01.intranet.prod.int.rdu2.redhat.com> (raw) In-Reply-To: <20160714125129.GA12289@dhcp22.suse.cz> On Thu, 14 Jul 2016, Michal Hocko wrote: > On Wed 13-07-16 11:02:15, Mikulas Patocka wrote: > > > diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c > > > index 4f3cb3554944..0b806810efab 100644 > > > --- a/drivers/md/dm-crypt.c > > > +++ b/drivers/md/dm-crypt.c > > > @@ -1392,11 +1392,14 @@ static void kcryptd_async_done(struct crypto_async_request *async_req, > > > static void kcryptd_crypt(struct work_struct *work) > > > { > > > struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); > > > + unsigned int pflags = current->flags; > > > > > > + current->flags |= PF_LESS_THROTTLE; > > > if (bio_data_dir(io->base_bio) == READ) > > > kcryptd_crypt_read_convert(io); > > > else > > > kcryptd_crypt_write_convert(io); > > > + tsk_restore_flags(current, pflags, PF_LESS_THROTTLE); > > > } > > > > > > static void kcryptd_queue_crypt(struct dm_crypt_io *io) > > > > ^^^ That fixes just one specific case - but there may be other threads > > doing mempool allocations in the device mapper subsystem - and you would > > need to mark all of them. > > Now that I am thinking about it some more. Are there any mempool users > which would actually want to be throttled? I would expect mempool users > are necessary to push IO through and throttle them sounds like a bad > decision in the first place but there might be other mempool users which > could cause issues. Anyway how about setting PF_LESS_THROTTLE > unconditionally inside mempool_alloc? Something like the following: > > diff --git a/mm/mempool.c b/mm/mempool.c > index 8f65464da5de..e21fb632983f 100644 > --- a/mm/mempool.c > +++ b/mm/mempool.c > @@ -310,7 +310,8 @@ EXPORT_SYMBOL(mempool_resize); > */ > void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) > { > - void *element; > + unsigned int pflags = current->flags; > + void *element = NULL; > unsigned long flags; > wait_queue_t wait; > gfp_t gfp_temp; > @@ -327,6 +328,12 @@ void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) > > gfp_temp = gfp_mask & ~(__GFP_DIRECT_RECLAIM|__GFP_IO); > > + /* > + * Make sure that the allocation doesn't get throttled during the > + * reclaim > + */ > + if (gfpflags_allow_blocking(gfp_mask)) > + current->flags |= PF_LESS_THROTTLE; > repeat_alloc: > if (likely(pool->curr_nr)) { > /* > @@ -339,7 +346,7 @@ void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) > > element = pool->alloc(gfp_temp, pool->pool_data); > if (likely(element != NULL)) > - return element; > + goto out; > > spin_lock_irqsave(&pool->lock, flags); > if (likely(pool->curr_nr)) { > @@ -352,7 +359,7 @@ void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) > * for debugging. > */ > kmemleak_update_trace(element); > - return element; > + goto out; > } > > /* > @@ -369,7 +376,7 @@ void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) > /* We must not sleep if !__GFP_DIRECT_RECLAIM */ > if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) { > spin_unlock_irqrestore(&pool->lock, flags); > - return NULL; > + goto out; > } > > /* Let's wait for someone else to return an element to @pool */ > @@ -386,6 +393,10 @@ void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) > > finish_wait(&pool->wait, &wait); > goto repeat_alloc; > +out: > + if (gfpflags_allow_blocking(gfp_mask)) > + tsk_restore_flags(current, pflags, PF_LESS_THROTTLE); > + return element; > } > EXPORT_SYMBOL(mempool_alloc); > But it needs other changes to honor the PF_LESS_THROTTLE flag: static int current_may_throttle(void) { return !(current->flags & PF_LESS_THROTTLE) || current->backing_dev_info == NULL || bdi_write_congested(current->backing_dev_info); } --- if you set PF_LESS_THROTTLE, current_may_throttle may still return true if one of the other conditions is met. shrink_zone_memcg calls throttle_vm_writeout without checking PF_LESS_THROTTLE at all. Mikulas
WARNING: multiple messages have this Message-ID (diff)
From: Mikulas Patocka <mpatocka@redhat.com> To: Michal Hocko <mhocko@kernel.org> Cc: Ondrej Kozina <okozina@redhat.com>, Jerome Marchand <jmarchan@redhat.com>, Stanislav Kozina <skozina@redhat.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com Subject: Re: System freezes after OOM Date: Thu, 14 Jul 2016 10:00:16 -0400 (EDT) [thread overview] Message-ID: <alpine.LRH.2.02.1607140952550.1102@file01.intranet.prod.int.rdu2.redhat.com> (raw) In-Reply-To: <20160714125129.GA12289@dhcp22.suse.cz> On Thu, 14 Jul 2016, Michal Hocko wrote: > On Wed 13-07-16 11:02:15, Mikulas Patocka wrote: > > > diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c > > > index 4f3cb3554944..0b806810efab 100644 > > > --- a/drivers/md/dm-crypt.c > > > +++ b/drivers/md/dm-crypt.c > > > @@ -1392,11 +1392,14 @@ static void kcryptd_async_done(struct crypto_async_request *async_req, > > > static void kcryptd_crypt(struct work_struct *work) > > > { > > > struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); > > > + unsigned int pflags = current->flags; > > > > > > + current->flags |= PF_LESS_THROTTLE; > > > if (bio_data_dir(io->base_bio) == READ) > > > kcryptd_crypt_read_convert(io); > > > else > > > kcryptd_crypt_write_convert(io); > > > + tsk_restore_flags(current, pflags, PF_LESS_THROTTLE); > > > } > > > > > > static void kcryptd_queue_crypt(struct dm_crypt_io *io) > > > > ^^^ That fixes just one specific case - but there may be other threads > > doing mempool allocations in the device mapper subsystem - and you would > > need to mark all of them. > > Now that I am thinking about it some more. Are there any mempool users > which would actually want to be throttled? I would expect mempool users > are necessary to push IO through and throttle them sounds like a bad > decision in the first place but there might be other mempool users which > could cause issues. Anyway how about setting PF_LESS_THROTTLE > unconditionally inside mempool_alloc? Something like the following: > > diff --git a/mm/mempool.c b/mm/mempool.c > index 8f65464da5de..e21fb632983f 100644 > --- a/mm/mempool.c > +++ b/mm/mempool.c > @@ -310,7 +310,8 @@ EXPORT_SYMBOL(mempool_resize); > */ > void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) > { > - void *element; > + unsigned int pflags = current->flags; > + void *element = NULL; > unsigned long flags; > wait_queue_t wait; > gfp_t gfp_temp; > @@ -327,6 +328,12 @@ void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) > > gfp_temp = gfp_mask & ~(__GFP_DIRECT_RECLAIM|__GFP_IO); > > + /* > + * Make sure that the allocation doesn't get throttled during the > + * reclaim > + */ > + if (gfpflags_allow_blocking(gfp_mask)) > + current->flags |= PF_LESS_THROTTLE; > repeat_alloc: > if (likely(pool->curr_nr)) { > /* > @@ -339,7 +346,7 @@ void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) > > element = pool->alloc(gfp_temp, pool->pool_data); > if (likely(element != NULL)) > - return element; > + goto out; > > spin_lock_irqsave(&pool->lock, flags); > if (likely(pool->curr_nr)) { > @@ -352,7 +359,7 @@ void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) > * for debugging. > */ > kmemleak_update_trace(element); > - return element; > + goto out; > } > > /* > @@ -369,7 +376,7 @@ void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) > /* We must not sleep if !__GFP_DIRECT_RECLAIM */ > if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) { > spin_unlock_irqrestore(&pool->lock, flags); > - return NULL; > + goto out; > } > > /* Let's wait for someone else to return an element to @pool */ > @@ -386,6 +393,10 @@ void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) > > finish_wait(&pool->wait, &wait); > goto repeat_alloc; > +out: > + if (gfpflags_allow_blocking(gfp_mask)) > + tsk_restore_flags(current, pflags, PF_LESS_THROTTLE); > + return element; > } > EXPORT_SYMBOL(mempool_alloc); > But it needs other changes to honor the PF_LESS_THROTTLE flag: static int current_may_throttle(void) { return !(current->flags & PF_LESS_THROTTLE) || current->backing_dev_info == NULL || bdi_write_congested(current->backing_dev_info); } --- if you set PF_LESS_THROTTLE, current_may_throttle may still return true if one of the other conditions is met. shrink_zone_memcg calls throttle_vm_writeout without checking PF_LESS_THROTTLE at all. Mikulas -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-07-14 14:00 UTC|newest] Thread overview: 136+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <57837CEE.1010609@redhat.com> [not found] ` <f80dc690-7e71-26b2-59a2-5a1557d26713@redhat.com> [not found] ` <9be09452-de7f-d8be-fd5d-4a80d1cd1ba3@redhat.com> 2016-07-11 15:43 ` System freezes after OOM Mikulas Patocka 2016-07-11 15:43 ` Mikulas Patocka 2016-07-12 6:49 ` Michal Hocko 2016-07-12 6:49 ` Michal Hocko 2016-07-12 23:44 ` Mikulas Patocka 2016-07-12 23:44 ` Mikulas Patocka 2016-07-12 23:44 ` Mikulas Patocka 2016-07-13 8:35 ` Jerome Marchand 2016-07-13 8:35 ` Jerome Marchand 2016-07-13 11:14 ` Michal Hocko 2016-07-13 11:14 ` Michal Hocko 2016-07-13 11:14 ` Michal Hocko 2016-07-13 14:21 ` Mikulas Patocka 2016-07-13 14:21 ` Mikulas Patocka 2016-07-13 11:10 ` Michal Hocko 2016-07-13 11:10 ` Michal Hocko 2016-07-13 11:10 ` Michal Hocko 2016-07-13 12:50 ` Michal Hocko 2016-07-13 12:50 ` Michal Hocko 2016-07-13 13:44 ` Milan Broz 2016-07-13 13:44 ` Milan Broz 2016-07-13 15:21 ` Mikulas Patocka 2016-07-13 15:21 ` Mikulas Patocka 2016-07-14 9:09 ` Michal Hocko 2016-07-14 9:09 ` Michal Hocko 2016-07-14 9:46 ` Milan Broz 2016-07-14 9:46 ` Milan Broz 2016-07-13 12:50 ` Michal Hocko 2016-07-13 15:02 ` Mikulas Patocka 2016-07-13 15:02 ` Mikulas Patocka 2016-07-13 15:02 ` Mikulas Patocka 2016-07-14 10:51 ` [dm-devel] " Ondrej Kozina 2016-07-14 10:51 ` Ondrej Kozina 2016-07-14 12:51 ` Michal Hocko 2016-07-14 12:51 ` Michal Hocko 2016-07-14 14:00 ` Mikulas Patocka [this message] 2016-07-14 14:00 ` Mikulas Patocka 2016-07-14 14:59 ` Michal Hocko 2016-07-14 14:59 ` Michal Hocko 2016-07-14 15:25 ` Ondrej Kozina 2016-07-14 15:25 ` Ondrej Kozina 2016-07-14 17:35 ` Mikulas Patocka 2016-07-14 17:35 ` Mikulas Patocka 2016-07-15 8:35 ` Michal Hocko 2016-07-15 8:35 ` Michal Hocko 2016-07-15 12:11 ` Mikulas Patocka 2016-07-15 12:11 ` Mikulas Patocka 2016-07-15 12:22 ` Michal Hocko 2016-07-15 12:22 ` Michal Hocko 2016-07-15 17:02 ` Mikulas Patocka 2016-07-15 17:02 ` Mikulas Patocka 2016-07-18 7:22 ` Michal Hocko 2016-07-18 7:22 ` Michal Hocko 2016-07-14 14:08 ` Ondrej Kozina 2016-07-14 14:08 ` Ondrej Kozina 2016-07-14 14:08 ` Ondrej Kozina 2016-07-14 15:31 ` Michal Hocko 2016-07-14 15:31 ` Michal Hocko 2016-07-14 17:07 ` Ondrej Kozina 2016-07-14 17:07 ` Ondrej Kozina 2016-07-14 17:36 ` Michal Hocko 2016-07-14 17:36 ` Michal Hocko 2016-07-14 17:39 ` Michal Hocko 2016-07-14 17:39 ` Michal Hocko 2016-07-15 11:42 ` Tetsuo Handa 2016-07-15 11:42 ` Tetsuo Handa 2016-07-13 13:19 ` Tetsuo Handa 2016-07-13 13:19 ` Tetsuo Handa 2016-07-13 13:39 ` Michal Hocko 2016-07-13 13:39 ` Michal Hocko 2016-07-13 14:18 ` Mikulas Patocka 2016-07-13 14:18 ` Mikulas Patocka 2016-07-13 14:18 ` Mikulas Patocka 2016-07-13 14:56 ` Michal Hocko 2016-07-13 14:56 ` Michal Hocko 2016-07-13 15:11 ` Mikulas Patocka 2016-07-13 15:11 ` Mikulas Patocka 2016-07-13 23:53 ` David Rientjes 2016-07-13 23:53 ` David Rientjes 2016-07-14 11:01 ` Tetsuo Handa 2016-07-14 11:01 ` Tetsuo Handa 2016-07-14 12:29 ` Mikulas Patocka 2016-07-14 12:29 ` Mikulas Patocka 2016-07-14 20:26 ` David Rientjes 2016-07-14 20:26 ` David Rientjes 2016-07-14 21:40 ` Tetsuo Handa 2016-07-14 21:40 ` Tetsuo Handa 2016-07-14 22:04 ` David Rientjes 2016-07-14 22:04 ` David Rientjes 2016-07-15 11:25 ` Mikulas Patocka 2016-07-15 11:25 ` Mikulas Patocka 2016-07-15 21:21 ` David Rientjes 2016-07-15 21:21 ` David Rientjes 2016-07-14 11:01 ` Tetsuo Handa 2016-07-14 12:27 ` Mikulas Patocka 2016-07-14 12:27 ` Mikulas Patocka 2016-07-14 20:22 ` David Rientjes 2016-07-14 20:22 ` David Rientjes 2016-07-15 11:21 ` Mikulas Patocka 2016-07-15 11:21 ` Mikulas Patocka 2016-07-15 21:25 ` David Rientjes 2016-07-15 21:25 ` David Rientjes 2016-07-15 21:39 ` Mikulas Patocka 2016-07-15 21:39 ` Mikulas Patocka 2016-07-15 21:58 ` David Rientjes 2016-07-15 21:58 ` David Rientjes 2016-07-15 23:53 ` Mikulas Patocka 2016-07-15 23:53 ` Mikulas Patocka 2016-07-18 15:14 ` Johannes Weiner 2016-07-18 15:14 ` Johannes Weiner 2016-07-14 15:29 ` Michal Hocko 2016-07-14 15:29 ` Michal Hocko 2016-07-14 20:38 ` David Rientjes 2016-07-14 20:38 ` David Rientjes 2016-07-15 7:22 ` Michal Hocko 2016-07-15 7:22 ` Michal Hocko 2016-07-15 8:23 ` Michal Hocko 2016-07-15 8:23 ` Michal Hocko 2016-07-15 12:00 ` Mikulas Patocka 2016-07-15 12:00 ` Mikulas Patocka 2016-07-15 21:47 ` David Rientjes 2016-07-15 21:47 ` David Rientjes 2016-07-18 7:39 ` Michal Hocko 2016-07-18 7:39 ` Michal Hocko 2016-07-18 21:03 ` David Rientjes 2016-07-18 21:03 ` David Rientjes 2016-07-13 23:53 ` David Rientjes 2016-07-13 15:11 ` Mikulas Patocka 2016-07-13 14:56 ` Michal Hocko 2016-07-13 13:39 ` Michal Hocko 2016-07-14 0:01 ` David Rientjes 2016-07-14 0:01 ` David Rientjes 2016-07-14 0:01 ` David Rientjes 2016-07-13 13:19 ` Tetsuo Handa 2016-07-12 6:49 ` Michal Hocko 2016-07-11 15:43 ` Mikulas Patocka
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