Jens Axboe [Fri, 24 Mar 2017 18:04:19 +0000 (12:04 -0600)]
blk-mq: include errors in did_work calculation
Currently we return true in blk_mq_dispatch_rq_list() if we queued IO
successfully, but we really want to return whether or not the we made
progress. Progress includes if we got an error return. If we don't,
this can lead to a hang in blk_mq_sched_dispatch_requests() when a
driver is draining IO by returning BLK_MQ_QUEUE_ERROR instead of
manually ending the IO in error and return BLK_MQ_QUEUE_OK.
Tested-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Josef Bacik [Tue, 28 Mar 2017 20:37:52 +0000 (16:37 -0400)]
block-mq: don't re-queue if we get a queue error
When try to issue a request directly and we fail we will requeue the
request, but call blk_mq_end_request() as well. This leads to the
completed request being on a queuelist and getting ended twice, which
causes list corruption in schedulers and other shenanigans.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
Tahsin Erdogan [Wed, 29 Mar 2017 17:27:19 +0000 (11:27 -0600)]
blkcg: allocate struct blkcg_gq outside request queue spinlock
blkg_conf_prep() currently calls blkg_lookup_create() while holding
request queue spinlock. This means allocating memory for struct
blkcg_gq has to be made non-blocking. This causes occasional -ENOMEM
failures in call paths like below:
pcpu_alloc+0x68f/0x710
__alloc_percpu_gfp+0xd/0x10
__percpu_counter_init+0x55/0xc0
cfq_pd_alloc+0x3b2/0x4e0
blkg_alloc+0x187/0x230
blkg_create+0x489/0x670
blkg_lookup_create+0x9a/0x230
blkg_conf_prep+0x1fb/0x240
__cfqg_set_weight_device.isra.105+0x5c/0x180
cfq_set_weight_on_dfl+0x69/0xc0
cgroup_file_write+0x39/0x1c0
kernfs_fop_write+0x13f/0x1d0
__vfs_write+0x23/0x120
vfs_write+0xc2/0x1f0
SyS_write+0x44/0xb0
entry_SYSCALL_64_fastpath+0x18/0xad
In the code path above, percpu allocator cannot call vmalloc() due to
queue spinlock.
A failure in this call path gives grief to tools which are trying to
configure io weights. We see occasional failures happen shortly after
reboots even when system is not under any memory pressure. Machines
with a lot of cpus are more vulnerable to this condition.
Do struct blkcg_gq allocations outside the queue spinlock to allow
blocking during memory allocations.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
Jens Axboe [Wed, 29 Mar 2017 17:25:48 +0000 (11:25 -0600)]
Revert "blkcg: allocate struct blkcg_gq outside request queue spinlock"
I inadvertently applied the v5 version of this patch, whereas
the agreed upon version was v5. Revert this one so we can apply
the right one.
This reverts commit
7fc6b87a9ff537e7df32b1278118ce9c5bcd6788.
Jens Axboe [Wed, 29 Mar 2017 17:10:34 +0000 (11:10 -0600)]
blk-mq: fix a typo and a spelling mistake
Signed-off-by: Jens Axboe <axboe@fb.com>
Sagi Grimberg [Wed, 29 Mar 2017 17:04:36 +0000 (20:04 +0300)]
blk-mq-pci: Fix two spelling mistakes
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
Omar Sandoval [Tue, 28 Mar 2017 23:12:17 +0000 (16:12 -0700)]
block: fix leak of q->rq_wb
CONFIG_DEBUG_TEST_DRIVER_REMOVE found a possible leak of q->rq_wb when a
request queue is reregistered. This has been a problem since wbt was
introduced, but the WARN_ON(!list_empty(&stats->callbacks)) in the
blk-stat rework exposed it. Fix it by cleaning up wbt when we unregister
the queue.
Fixes: 87760e5eef35 ("block: hook up writeback throttling")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Omar Sandoval [Tue, 28 Mar 2017 23:12:16 +0000 (16:12 -0700)]
blk-mq: fix leak of q->stats
blk_alloc_queue_node() already allocates q->stats, so
blk_mq_init_allocated_queue() is overwriting it with a new allocation.
Fixes: a83b576c9c25 ("block: fix stacked driver stats init and free")
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Omar Sandoval [Tue, 28 Mar 2017 23:12:15 +0000 (16:12 -0700)]
block: warn if sharing request queue across gendisks
Now that the remaining drivers have been converted to one request queue
per gendisk, let's warn if a request queue gets registered more than
once. This will catch future drivers which might do it inadvertently or
any old drivers that I may have missed.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Ming Lei [Mon, 27 Mar 2017 12:06:58 +0000 (20:06 +0800)]
block: block new I/O just after queue is set as dying
Before commit
780db2071a(blk-mq: decouble blk-mq freezing
from generic bypassing), the dying flag is checked before
entering queue, and Tejun converts the checking into .mq_freeze_depth,
and assumes the counter is increased just after dying flag
is set. Unfortunately we doesn't do that in blk_set_queue_dying().
This patch calls blk_freeze_queue_start() in blk_set_queue_dying(),
so that we can block new I/O coming once the queue is set as dying.
Given blk_set_queue_dying() is always called in remove path
of block device, and queue will be cleaned up later, we don't
need to worry about undoing the counter.
Cc: Tejun Heo <tj@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Ming Lei [Mon, 27 Mar 2017 12:06:57 +0000 (20:06 +0800)]
block: rename blk_mq_freeze_queue_start()
As the .q_usage_counter is used by both legacy and
mq path, we need to block new I/O if queue becomes
dead in blk_queue_enter().
So rename it and we can use this function in both
paths.
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Ming Lei [Mon, 27 Mar 2017 12:06:56 +0000 (20:06 +0800)]
block: add a read barrier in blk_queue_enter()
Without the barrier, reading DEAD flag of .q_usage_counter
and reading .mq_freeze_depth may be reordered, then the
following wait_event_interruptible() may never return.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Ming Lei [Mon, 27 Mar 2017 12:06:55 +0000 (20:06 +0800)]
blk-mq: comment on races related with timeout handler
This patch adds comment on two races related with
timeout handler:
- requeue from queue busy vs. timeout
- rq free & reallocation vs. timeout
Both the races themselves and current solution aren't
explicit enough, so add comments on them.
Cc: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Ming Lei [Wed, 22 Mar 2017 02:14:43 +0000 (10:14 +0800)]
blk-mq: don't complete un-started request in timeout handler
When iterating busy requests in timeout handler,
if the STARTED flag of one request isn't set, that means
the request is being processed in block layer or driver, and
isn't submitted to hardware yet.
In current implementation of blk_mq_check_expired(),
if the request queue becomes dying, un-started requests are
handled as being completed/freed immediately. This way is
wrong, and can cause rq corruption or double allocation[1][2],
when doing I/O and removing&resetting NVMe device at the sametime.
This patch fixes several issues reported by Yi Zhang.
[1]. oops log 1
[ 581.789754] ------------[ cut here ]------------
[ 581.789758] kernel BUG at block/blk-mq.c:374!
[ 581.789760] invalid opcode: 0000 [#1] SMP
[ 581.789761] Modules linked in: vfat fat ipmi_ssif intel_rapl sb_edac
edac_core x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm nvme
irqbypass crct10dif_pclmul nvme_core crc32_pclmul ghash_clmulni_intel
intel_cstate ipmi_si mei_me ipmi_devintf intel_uncore sg ipmi_msghandler
intel_rapl_perf iTCO_wdt mei iTCO_vendor_support mxm_wmi lpc_ich dcdbas shpchp
pcspkr acpi_power_meter wmi nfsd auth_rpcgss nfs_acl lockd dm_multipath grace
sunrpc ip_tables xfs libcrc32c sd_mod mgag200 i2c_algo_bit drm_kms_helper
syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm ahci libahci
crc32c_intel tg3 libata megaraid_sas i2c_core ptp fjes pps_core dm_mirror
dm_region_hash dm_log dm_mod
[ 581.789796] CPU: 1 PID: 1617 Comm: kworker/1:1H Not tainted 4.10.0.bz1420297+ #4
[ 581.789797] Hardware name: Dell Inc. PowerEdge R730xd/072T6D, BIOS 2.2.5 09/06/2016
[ 581.789804] Workqueue: kblockd blk_mq_timeout_work
[ 581.789806] task:
ffff8804721c8000 task.stack:
ffffc90006ee4000
[ 581.789809] RIP: 0010:blk_mq_end_request+0x58/0x70
[ 581.789810] RSP: 0018:
ffffc90006ee7d50 EFLAGS:
00010202
[ 581.789811] RAX:
0000000000000001 RBX:
ffff8802e4195340 RCX:
ffff88028e2f4b88
[ 581.789812] RDX:
0000000000001000 RSI:
0000000000001000 RDI:
0000000000000000
[ 581.789813] RBP:
ffffc90006ee7d60 R08:
0000000000000003 R09:
ffff88028e2f4b00
[ 581.789814] R10:
0000000000001000 R11:
0000000000000001 R12:
00000000fffffffb
[ 581.789815] R13:
ffff88042abe5780 R14:
000000000000002d R15:
ffff88046fbdff80
[ 581.789817] FS:
0000000000000000(0000) GS:
ffff88047fc00000(0000) knlGS:
0000000000000000
[ 581.789818] CS: 0010 DS: 0000 ES: 0000 CR0:
0000000080050033
[ 581.789819] CR2:
00007f64f403a008 CR3:
000000014d078000 CR4:
00000000001406e0
[ 581.789820] Call Trace:
[ 581.789825] blk_mq_check_expired+0x76/0x80
[ 581.789828] bt_iter+0x45/0x50
[ 581.789830] blk_mq_queue_tag_busy_iter+0xdd/0x1f0
[ 581.789832] ? blk_mq_rq_timed_out+0x70/0x70
[ 581.789833] ? blk_mq_rq_timed_out+0x70/0x70
[ 581.789840] ? __switch_to+0x140/0x450
[ 581.789841] blk_mq_timeout_work+0x88/0x170
[ 581.789845] process_one_work+0x165/0x410
[ 581.789847] worker_thread+0x137/0x4c0
[ 581.789851] kthread+0x101/0x140
[ 581.789853] ? rescuer_thread+0x3b0/0x3b0
[ 581.789855] ? kthread_park+0x90/0x90
[ 581.789860] ret_from_fork+0x2c/0x40
[ 581.789861] Code: 48 85 c0 74 0d 44 89 e6 48 89 df ff d0 5b 41 5c 5d c3 48
8b bb 70 01 00 00 48 85 ff 75 0f 48 89 df e8 7d f0 ff ff 5b 41 5c 5d c3 <0f>
0b e8 71 f0 ff ff 90 eb e9 0f 1f 40 00 66 2e 0f 1f 84 00 00
[ 581.789882] RIP: blk_mq_end_request+0x58/0x70 RSP:
ffffc90006ee7d50
[ 581.789889] ---[ end trace
bcaf03d9a14a0a70 ]---
[2]. oops log2
[ 6984.857362] BUG: unable to handle kernel NULL pointer dereference at
0000000000000010
[ 6984.857372] IP: nvme_queue_rq+0x6e6/0x8cd [nvme]
[ 6984.857373] PGD 0
[ 6984.857374]
[ 6984.857376] Oops: 0000 [#1] SMP
[ 6984.857379] Modules linked in: ipmi_ssif vfat fat intel_rapl sb_edac
edac_core x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm
irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel ipmi_si iTCO_wdt
iTCO_vendor_support mxm_wmi ipmi_devintf intel_cstate sg dcdbas intel_uncore
mei_me intel_rapl_perf mei pcspkr lpc_ich ipmi_msghandler shpchp
acpi_power_meter wmi nfsd auth_rpcgss dm_multipath nfs_acl lockd grace sunrpc
ip_tables xfs libcrc32c sd_mod mgag200 i2c_algo_bit drm_kms_helper syscopyarea
sysfillrect crc32c_intel sysimgblt fb_sys_fops ttm nvme drm nvme_core ahci
libahci i2c_core tg3 libata ptp megaraid_sas pps_core fjes dm_mirror
dm_region_hash dm_log dm_mod
[ 6984.857416] CPU: 7 PID: 1635 Comm: kworker/7:1H Not tainted
4.10.0-2.el7.bz1420297.x86_64 #1
[ 6984.857417] Hardware name: Dell Inc. PowerEdge R730xd/072T6D, BIOS 2.2.5 09/06/2016
[ 6984.857427] Workqueue: kblockd blk_mq_run_work_fn
[ 6984.857429] task:
ffff880476e3da00 task.stack:
ffffc90002e90000
[ 6984.857432] RIP: 0010:nvme_queue_rq+0x6e6/0x8cd [nvme]
[ 6984.857433] RSP: 0018:
ffffc90002e93c50 EFLAGS:
00010246
[ 6984.857434] RAX:
0000000000000000 RBX:
ffff880275646600 RCX:
0000000000001000
[ 6984.857435] RDX:
0000000000000fff RSI:
00000002fba2a000 RDI:
ffff8804734e6950
[ 6984.857436] RBP:
ffffc90002e93d30 R08:
0000000000002000 R09:
0000000000001000
[ 6984.857437] R10:
0000000000001000 R11:
0000000000000000 R12:
ffff8804741d8000
[ 6984.857438] R13:
0000000000000040 R14:
ffff880475649f80 R15:
ffff8804734e6780
[ 6984.857439] FS:
0000000000000000(0000) GS:
ffff88047fcc0000(0000) knlGS:
0000000000000000
[ 6984.857440] CS: 0010 DS: 0000 ES: 0000 CR0:
0000000080050033
[ 6984.857442] CR2:
0000000000000010 CR3:
0000000001c09000 CR4:
00000000001406e0
[ 6984.857443] Call Trace:
[ 6984.857451] ? mempool_free+0x2b/0x80
[ 6984.857455] ? bio_free+0x4e/0x60
[ 6984.857459] blk_mq_dispatch_rq_list+0xf5/0x230
[ 6984.857462] blk_mq_process_rq_list+0x133/0x170
[ 6984.857465] __blk_mq_run_hw_queue+0x8c/0xa0
[ 6984.857467] blk_mq_run_work_fn+0x12/0x20
[ 6984.857473] process_one_work+0x165/0x410
[ 6984.857475] worker_thread+0x137/0x4c0
[ 6984.857478] kthread+0x101/0x140
[ 6984.857480] ? rescuer_thread+0x3b0/0x3b0
[ 6984.857481] ? kthread_park+0x90/0x90
[ 6984.857489] ret_from_fork+0x2c/0x40
[ 6984.857490] Code: 8b bd 70 ff ff ff 89 95 50 ff ff ff 89 8d 58 ff ff ff 44
89 95 60 ff ff ff e8 b7 dd 12 e1 8b 95 50 ff ff ff 48 89 85 68 ff ff ff <4c>
8b 48 10 44 8b 58 18 8b 8d 58 ff ff ff 44 8b 95 60 ff ff ff
[ 6984.857511] RIP: nvme_queue_rq+0x6e6/0x8cd [nvme] RSP:
ffffc90002e93c50
[ 6984.857512] CR2:
0000000000000010
[ 6984.895359] ---[ end trace
2d7ceb528432bf83 ]---
Cc: stable@vger.kernel.org
Reported-by: Yi Zhang <yizhan@redhat.com>
Tested-by: Yi Zhang <yizhan@redhat.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Tahsin Erdogan [Thu, 9 Mar 2017 08:05:31 +0000 (00:05 -0800)]
blkcg: allocate struct blkcg_gq outside request queue spinlock
blkg_conf_prep() currently calls blkg_lookup_create() while holding
request queue spinlock. This means allocating memory for struct
blkcg_gq has to be made non-blocking. This causes occasional -ENOMEM
failures in call paths like below:
pcpu_alloc+0x68f/0x710
__alloc_percpu_gfp+0xd/0x10
__percpu_counter_init+0x55/0xc0
cfq_pd_alloc+0x3b2/0x4e0
blkg_alloc+0x187/0x230
blkg_create+0x489/0x670
blkg_lookup_create+0x9a/0x230
blkg_conf_prep+0x1fb/0x240
__cfqg_set_weight_device.isra.105+0x5c/0x180
cfq_set_weight_on_dfl+0x69/0xc0
cgroup_file_write+0x39/0x1c0
kernfs_fop_write+0x13f/0x1d0
__vfs_write+0x23/0x120
vfs_write+0xc2/0x1f0
SyS_write+0x44/0xb0
entry_SYSCALL_64_fastpath+0x18/0xad
In the code path above, percpu allocator cannot call vmalloc() due to
queue spinlock.
A failure in this call path gives grief to tools which are trying to
configure io weights. We see occasional failures happen shortly after
reboots even when system is not under any memory pressure. Machines
with a lot of cpus are more vulnerable to this condition.
Update blkg_create() function to temporarily drop the rcu and queue
locks when it is allowed by gfp mask.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
Omar Sandoval [Tue, 28 Mar 2017 06:28:47 +0000 (23:28 -0700)]
jsflash: stop sharing request queue across multiple gendisks
Compile-tested only (by hacking it to compile on x86).
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Omar Sandoval [Tue, 28 Mar 2017 06:28:46 +0000 (23:28 -0700)]
swim: stop sharing request queue across multiple gendisks
Compile-tested only (by hacking it to compile on x86).
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Omar Sandoval [Tue, 28 Mar 2017 06:28:45 +0000 (23:28 -0700)]
parport/pf: stop sharing request queue across multiple gendisks
Compile-tested only.
Cc: Tim Waugh <tim@cyberelk.net>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Omar Sandoval [Tue, 28 Mar 2017 06:28:44 +0000 (23:28 -0700)]
parport/pcd: stop sharing request queue across multiple gendisks
Compile-tested only.
Cc: Tim Waugh <tim@cyberelk.net>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Omar Sandoval [Tue, 28 Mar 2017 06:28:43 +0000 (23:28 -0700)]
parport/pd: stop sharing request queue across multiple gendisks
Compile-tested only.
Cc: Tim Waugh <tim@cyberelk.net>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Omar Sandoval [Tue, 28 Mar 2017 06:28:42 +0000 (23:28 -0700)]
hd: stop sharing request queue across multiple gendisks
Compile-tested only.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 22:19:43 +0000 (15:19 -0700)]
blk-throttle: add latency target support
One hard problem adding .low limit is to detect idle cgroup. If one
cgroup doesn't dispatch enough IO against its low limit, we must have a
mechanism to determine if other cgroups dispatch more IO. We added the
think time detection mechanism before, but it doesn't work for all
workloads. Here we add a latency based approach.
We already have mechanism to calculate latency threshold for each IO
size. For every IO dispatched from a cgorup, we compare its latency
against its threshold and record the info. If most IO latency is below
threshold (in the code I use 75%), the cgroup could be treated idle and
other cgroups can dispatch more IO.
Currently this latency target check is only for SSD as we can't
calcualte the latency target for hard disk. And this is only for cgroup
leaf node so far.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 22:19:42 +0000 (15:19 -0700)]
blk-throttle: add a mechanism to estimate IO latency
User configures latency target, but the latency threshold for each
request size isn't fixed. For a SSD, the IO latency highly depends on
request size. To calculate latency threshold, we sample some data, eg,
average latency for request size 4k, 8k, 16k, 32k .. 1M. The latency
threshold of each request size will be the sample latency (I'll call it
base latency) plus latency target. For example, the base latency for
request size 4k is 80us and user configures latency target 60us. The 4k
latency threshold will be 80 + 60 = 140us.
To sample data, we calculate the order base 2 of rounded up IO sectors.
If the IO size is bigger than 1M, it will be accounted as 1M. Since the
calculation does round up, the base latency will be slightly smaller
than actual value. Also if there isn't any IO dispatched for a specific
IO size, we will use the base latency of smaller IO size for this IO
size.
But we shouldn't sample data at any time. The base latency is supposed
to be latency where disk isn't congested, because we use latency
threshold to schedule IOs between cgroups. If disk is congested, the
latency is higher, using it for scheduling is meaningless. Hence we only
do the sampling when block throttling is in the LOW limit, with
assumption disk isn't congested in such state. If the assumption isn't
true, eg, low limit is too high, calculated latency threshold will be
higher.
Hard disk is completely different. Latency depends on spindle seek
instead of request size. Currently this feature is SSD only, we probably
can use a fixed threshold like 4ms for hard disk though.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 22:19:41 +0000 (15:19 -0700)]
block: track request size in blk_issue_stat
Currently there is no way to know the request size when the request is
finished. Next patch will need this info. We could add extra field to
record the size, but blk_issue_stat has enough space to record it, so
this patch just overloads blk_issue_stat. With this, we will have 49bits
to track time, which still is very long time.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:44 +0000 (10:51 -0700)]
blk-throttle: add interface for per-cgroup target latency
Here we introduce per-cgroup latency target. The target determines how a
cgroup can afford latency increasement. We will use the target latency
to calculate a threshold and use it to schedule IO for cgroups. If a
cgroup's bandwidth is below its low limit but its average latency is
below the threshold, other cgroups can safely dispatch more IO even
their bandwidth is higher than their low limits. On the other hand, if
the first cgroup's latency is higher than the threshold, other cgroups
are throttled to their low limits. So the target latency determines how
we efficiently utilize free disk resource without sacifice of worload's
IO latency.
For example, assume 4k IO average latency is 50us when disk isn't
congested. A cgroup sets the target latency to 30us. Then the cgroup can
accept 50+30=80us IO latency. If the cgroupt's average IO latency is
90us and its bandwidth is below low limit, other cgroups are throttled
to their low limit. If the cgroup's average IO latency is 60us, other
cgroups are allowed to dispatch more IO. When other cgroups dispatch
more IO, the first cgroup's IO latency will increase. If it increases to
81us, we then throttle other cgroups.
User will configure the interface in this way:
echo "8:16 rbps=
2097152 wbps=max latency=100 idle=200" > io.low
latency is in microsecond unit
By default, latency target is 0, which means to guarantee IO latency.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:43 +0000 (10:51 -0700)]
blk-throttle: ignore idle cgroup limit
Last patch introduces a way to detect idle cgroup. We use it to make
upgrade/downgrade decision. And the new algorithm can detect completely
idle cgroup too, so we can delete the corresponding code.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:42 +0000 (10:51 -0700)]
blk-throttle: add interface to configure idle time threshold
Add interface to configure the threshold. The io.low interface will
like:
echo "8:16 rbps=
2097152 wbps=max idle=2000" > io.low
idle is in microsecond unit.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:41 +0000 (10:51 -0700)]
blk-throttle: add a simple idle detection
A cgroup gets assigned a low limit, but the cgroup could never dispatch
enough IO to cross the low limit. In such case, the queue state machine
will remain in LIMIT_LOW state and all other cgroups will be throttled
according to low limit. This is unfair for other cgroups. We should
treat the cgroup idle and upgrade the state machine to lower state.
We also have a downgrade logic. If the state machine upgrades because of
cgroup idle (real idle), the state machine will downgrade soon as the
cgroup is below its low limit. This isn't what we want. A more
complicated case is cgroup isn't idle when queue is in LIMIT_LOW. But
when queue gets upgraded to lower state, other cgroups could dispatch
more IO and this cgroup can't dispatch enough IO, so the cgroup is below
its low limit and looks like idle (fake idle). In this case, the queue
should downgrade soon. The key to determine if we should do downgrade is
to detect if cgroup is truely idle.
Unfortunately it's very hard to determine if a cgroup is real idle. This
patch uses the 'think time check' idea from CFQ for the purpose. Please
note, the idea doesn't work for all workloads. For example, a workload
with io depth 8 has disk utilization 100%, hence think time is 0, eg,
not idle. But the workload can run higher bandwidth with io depth 16.
Compared to io depth 16, the io depth 8 workload is idle. We use the
idea to roughly determine if a cgroup is idle.
We treat a cgroup idle if its think time is above a threshold (by
default 1ms for SSD and 100ms for HD). The idea is think time above the
threshold will start to harm performance. HD is much slower so a longer
think time is ok.
The patch (and the latter patches) uses 'unsigned long' to track time.
We convert 'ns' to 'us' with 'ns >> 10'. This is fast but loses
precision, should not a big deal.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:40 +0000 (10:51 -0700)]
blk-throttle: make bandwidth change smooth
When cgroups all reach low limit, cgroups can dispatch more IO. This
could make some cgroups dispatch more IO but others not, and even some
cgroups could dispatch less IO than their low limit. For example, cg1
low limit 10MB/s, cg2 limit 80MB/s, assume disk maximum bandwidth is
120M/s for the workload. Their bps could something like this:
cg1/cg2 bps: T1: 10/80 -> T2: 60/60 -> T3: 10/80
At T1, all cgroups reach low limit, so they can dispatch more IO later.
Then cg1 dispatch more IO and cg2 has no room to dispatch enough IO. At
T2, cg2 only dispatches 60M/s. Since We detect cg2 dispatches less IO
than its low limit 80M/s, we downgrade the queue from LIMIT_MAX to
LIMIT_LOW, then all cgroups are throttled to their low limit (T3). cg2
will have bandwidth below its low limit at most time.
The big problem here is we don't know the maximum bandwidth of the
workload, so we can't make smart decision to avoid the situation. This
patch makes cgroup bandwidth change smooth. After disk upgrades from
LIMIT_LOW to LIMIT_MAX, we don't allow cgroups use all bandwidth upto
their max limit immediately. Their bandwidth limit will be increased
gradually to avoid above situation. So above example will became
something like:
cg1/cg2 bps: 10/80 -> 15/105 -> 20/100 -> 25/95 -> 30/90 -> 35/85 -> 40/80
-> 45/75 -> 22/98
In this way cgroups bandwidth will be above their limit in majority
time, this still doesn't fully utilize disk bandwidth, but that's
something we pay for sharing.
Scale up is linear. The limit scales up 1/2 .low limit every
throtl_slice after upgrade. The scale up will stop if the adjusted limit
hits .max limit. Scale down is exponential. We cut the scale value half
if a cgroup doesn't hit its .low limit. If the scale becomes 0, we then
fully downgrade the queue to LIMIT_LOW state.
Note this doesn't completely avoid cgroup running under its low limit.
The best way to guarantee cgroup doesn't run under its limit is to set
max limit. For example, if we set cg1 max limit to 40, cg2 will never
run under its low limit.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:39 +0000 (10:51 -0700)]
blk-throttle: detect completed idle cgroup
cgroup could be assigned a limit, but doesn't dispatch enough IO, eg the
cgroup is idle. When this happens, the cgroup doesn't hit its limit, so
we can't move the state machine to higher level and all cgroups will be
throttled to their lower limit, so we waste bandwidth. Detecting idle
cgroup is hard. This patch handles a simple case, a cgroup doesn't
dispatch any IO. We ignore such cgroup's limit, so other cgroups can use
the bandwidth.
Please note this will be replaced with a more sophisticated algorithm
later, but this demonstrates the idea how we handle idle cgroups, so I
leave it here.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:38 +0000 (10:51 -0700)]
blk-throttle: choose a small throtl_slice for SSD
The throtl_slice is 100ms by default. This is a long time for SSD, a lot
of IO can run. To make cgroups have smoother throughput, we choose a
small value (20ms) for SSD.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:37 +0000 (10:51 -0700)]
blk-throttle: make throtl_slice tunable
throtl_slice is important for blk-throttling. It's called slice
internally but it really is a time window blk-throttling samples data.
blk-throttling will make decision based on the samplings. An example is
bandwidth measurement. A cgroup's bandwidth is measured in the time
interval of throtl_slice.
A small throtl_slice meanse cgroups have smoother throughput but burn
more CPUs. It has 100ms default value, which is not appropriate for all
disks. A fast SSD can dispatch a lot of IOs in 100ms. This patch makes
it tunable.
Since throtl_slice isn't a time slice, the sysfs name
'throttle_sample_time' reflects its character better.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:36 +0000 (10:51 -0700)]
blk-throttle: make sure expire time isn't too big
cgroup could be throttled to a limit but when all cgroups cross high
limit, queue enters a higher state and so the group should be throttled
to a higher limit. It's possible the cgroup is sleeping because of
throttle and other cgroups don't dispatch IO any more. In this case,
nobody can trigger current downgrade/upgrade logic. To fix this issue,
we could either set up a timer to wakeup the cgroup if other cgroups are
idle or make sure this cgroup doesn't sleep too long. Setting up a timer
means we must change the timer very frequently. This patch chooses the
latter. Making cgroup sleep time not too big wouldn't change cgroup
bps/iops, but could make it wakeup more frequently, which isn't a big
issue because throtl_slice * 8 is already quite big.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:35 +0000 (10:51 -0700)]
blk-throttle: add downgrade logic
When queue state machine is in LIMIT_MAX state, but a cgroup is below
its low limit for some time, the queue should be downgraded to lower
state as one cgroup's low limit isn't met.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:34 +0000 (10:51 -0700)]
blk-throttle: add upgrade logic for LIMIT_LOW state
When queue is in LIMIT_LOW state and all cgroups with low limit cross
the bps/iops limitation, we will upgrade queue's state to
LIMIT_MAX. To determine if a cgroup exceeds its limitation, we check if
the cgroup has pending request. Since cgroup is throttled according to
the limit, pending request means the cgroup reaches the limit.
If a cgroup has limit set for both read and write, we consider the
combination of them for upgrade. The reason is read IO and write IO can
interfere with each other. If we do the upgrade based in one direction
IO, the other direction IO could be severly harmed.
For a cgroup hierarchy, there are two cases. Children has lower low
limit than parent. Parent's low limit is meaningless. If children's
bps/iops cross low limit, we can upgrade queue state. The other case is
children has higher low limit than parent. Children's low limit is
meaningless. As long as parent's bps/iops (which is a sum of childrens
bps/iops) cross low limit, we can upgrade queue state.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:33 +0000 (10:51 -0700)]
blk-throttle: configure bps/iops limit for cgroup in low limit
each queue will have a state machine. Initially queue is in LIMIT_LOW
state, which means all cgroups will be throttled according to their low
limit. After all cgroups with low limit cross the limit, the queue state
gets upgraded to LIMIT_MAX state.
For max limit, cgroup will use the limit configured by user.
For low limit, cgroup will use the minimal value between low limit and
max limit configured by user. If the minimal value is 0, which means the
cgroup doesn't configure low limit, we will use max limit to throttle
the cgroup and the cgroup is ready to upgrade to LIMIT_MAX
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:32 +0000 (10:51 -0700)]
blk-throttle: add .low interface
Add low limit for cgroup and corresponding cgroup interface. To be
consistent with memcg, we allow users configure .low limit higher than
.max limit. But the internal logic always assumes .low limit is lower
than .max limit. So we add extra bps/iops_conf fields in throtl_grp for
userspace configuration. Old bps/iops fields in throtl_grp will be the
actual limit we use for throttling.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:31 +0000 (10:51 -0700)]
blk-throttle: add configure option for new .low interface
As discussed in LSF, add configure option for the interface and mark it
as experimental, so people can try/test.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:30 +0000 (10:51 -0700)]
blk-throttle: prepare support multiple limits
We are going to support low/max limit, each cgroup will have 2 limits
after that. This patch prepares for the multiple limits change.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Shaohua Li [Mon, 27 Mar 2017 17:51:29 +0000 (10:51 -0700)]
blk-throttle: use U64_MAX/UINT_MAX to replace -1
clean up the code to avoid using -1
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Eric Biggers [Sat, 25 Mar 2017 01:03:48 +0000 (18:03 -0700)]
block: constify struct blk_integrity_profile
blk_integrity_profile's are never modified, so mark them 'const' so that
they are placed in .rodata and benefit from memory protection.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Eric Biggers [Mon, 23 Jan 2017 19:43:21 +0000 (11:43 -0800)]
block: remove outdated part of blkdev_issue_flush() comment
blkdev_issue_flush() is now always synchronous, and it no longer has a
flags argument. So remove the part of the comment about the WAIT flag.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Eric Biggers [Mon, 23 Jan 2017 19:41:39 +0000 (11:41 -0800)]
block: correct documentation for blkdev_issue_discard() flags
BLKDEV_IFL_* flags no longer exist; blkdev_issue_discard() now actually
takes BLKDEV_DISCARD_* flags.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Geliang Tang [Fri, 24 Mar 2017 14:15:13 +0000 (22:15 +0800)]
mg_disk: use setup_timer
Use setup_timer() instead of init_timer() to simplify the code.
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Geliang Tang [Fri, 24 Mar 2017 14:15:10 +0000 (22:15 +0800)]
block: floppy: use setup_timer
Use setup_timer() instead of init_timer() to simplify the code.
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Dan Carpenter [Thu, 23 Mar 2017 10:24:55 +0000 (13:24 +0300)]
block: make nr_iovecs unsigned in bio_alloc_bioset()
There isn't a bug here, but Smatch is not smart enough to know that
"nr_iovecs" can't be negative so it complains about underflows.
Really, it's slightly cleaner to make this parameter unsigned.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Christoph Hellwig [Wed, 22 Mar 2017 19:01:53 +0000 (15:01 -0400)]
blk-mq: streamline blk_mq_make_request
Turn the different ways of merging or issuing I/O into a series of if/else
statements instead of the current maze of gotos. Note that this means we
pin the CPU a little longer for some cases as the CTX put is moved to
common code at the end of the function.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Christoph Hellwig [Wed, 22 Mar 2017 19:01:52 +0000 (15:01 -0400)]
blk-mq: split the plug and sync cases in blk_mq_make_request
Now that we have a nice direct issue heper this helps simplifying
the code a bit, and also gets rid of the old_rq variable.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Christoph Hellwig [Wed, 22 Mar 2017 19:01:51 +0000 (15:01 -0400)]
blk-mq: improve blk_mq_try_issue_directly
Rename blk_mq_try_issue_directly to __blk_mq_try_issue_directly and add a
new wrapper that takes care of RCU / SRCU locking to avoid having
boileplate code in the caller which would get duplicated with new callers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Christoph Hellwig [Wed, 22 Mar 2017 19:01:50 +0000 (15:01 -0400)]
blk-mq: merge mq and sq make_request instances
They are mostly the same code anyway - this just one small conditional
for the plug case that is different for both variants.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Christoph Hellwig [Wed, 22 Mar 2017 19:01:49 +0000 (15:01 -0400)]
blk-mq: remove BLK_MQ_F_DEFER_ISSUE
This flag was never used since it was introduced.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Jan Kara [Thu, 23 Mar 2017 00:37:02 +0000 (01:37 +0100)]
block: Fix oops scsi_disk_get()
When device open races with device shutdown, we can get the following
oops in scsi_disk_get():
[11863.044351] general protection fault: 0000 [#1] SMP
[11863.045561] Modules linked in: scsi_debug xfs libcrc32c netconsole btrfs raid6_pq zlib_deflate lzo_compress xor [last unloaded: loop]
[11863.047853] CPU: 3 PID: 13042 Comm: hald-probe-stor Tainted: G W 4.10.0-rc2-xen+ #35
[11863.048030] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[11863.048030] task:
ffff88007f438200 task.stack:
ffffc90000fd0000
[11863.048030] RIP: 0010:scsi_disk_get+0x43/0x70
[11863.048030] RSP: 0018:
ffffc90000fd3a08 EFLAGS:
00010202
[11863.048030] RAX:
6b6b6b6b6b6b6b6b RBX:
ffff88007f56d000 RCX:
0000000000000000
[11863.048030] RDX:
0000000000000001 RSI:
0000000000000004 RDI:
ffffffff81a8d880
[11863.048030] RBP:
ffffc90000fd3a18 R08:
0000000000000000 R09:
0000000000000001
[11863.059217] R10:
0000000000000000 R11:
0000000000000000 R12:
00000000fffffffa
[11863.059217] R13:
ffff880078872800 R14:
ffff880070915540 R15:
000000000000001d
[11863.059217] FS:
00007f2611f71800(0000) GS:
ffff88007f0c0000(0000) knlGS:
0000000000000000
[11863.059217] CS: 0010 DS: 0000 ES: 0000 CR0:
0000000080050033
[11863.059217] CR2:
000000000060e048 CR3:
00000000778d4000 CR4:
00000000000006e0
[11863.059217] Call Trace:
[11863.059217] ? disk_get_part+0x22/0x1f0
[11863.059217] sd_open+0x39/0x130
[11863.059217] __blkdev_get+0x69/0x430
[11863.059217] ? bd_acquire+0x7f/0xc0
[11863.059217] ? bd_acquire+0x96/0xc0
[11863.059217] ? blkdev_get+0x350/0x350
[11863.059217] blkdev_get+0x126/0x350
[11863.059217] ? _raw_spin_unlock+0x2b/0x40
[11863.059217] ? bd_acquire+0x7f/0xc0
[11863.059217] ? blkdev_get+0x350/0x350
[11863.059217] blkdev_open+0x65/0x80
...
As you can see RAX value is already poisoned showing that gendisk we got
is already freed. The problem is that get_gendisk() looks up device
number in ext_devt_idr and then does get_disk() which does kobject_get()
on the disks kobject. However the disk gets removed from ext_devt_idr
only in disk_release() (through blk_free_devt()) at which moment it has
already 0 refcount and is already on its way to be freed. Indeed we've
got a warning from kobject_get() about 0 refcount shortly before the
oops.
We fix the problem by using kobject_get_unless_zero() in get_disk() so
that get_disk() cannot get reference on a disk that is already being
freed.
Tested-by: Lekshmi Pillai <lekshmicpillai@in.ibm.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Jan Kara [Thu, 23 Mar 2017 00:37:01 +0000 (01:37 +0100)]
kobject: Export kobject_get_unless_zero()
Make the function available for outside use and fortify it against NULL
kobject.
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Jan Kara [Thu, 23 Mar 2017 00:37:00 +0000 (01:37 +0100)]
block: Fix oops in locked_inode_to_wb_and_lock_list()
When block device is closed, we call inode_detach_wb() in __blkdev_put()
which sets inode->i_wb to NULL. That is contrary to expectations that
inode->i_wb stays valid once set during the whole inode's lifetime and
leads to oops in wb_get() in locked_inode_to_wb_and_lock_list() because
inode_to_wb() returned NULL.
The reason why we called inode_detach_wb() is not valid anymore though.
BDI is guaranteed to stay along until we call bdi_put() from
bdev_evict_inode() so we can postpone calling inode_detach_wb() to that
moment.
Also add a warning to catch if someone uses inode_detach_wb() in a
dangerous way.
Reported-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Jan Kara [Thu, 23 Mar 2017 00:36:59 +0000 (01:36 +0100)]
bdi: Rename cgwb_bdi_destroy() to cgwb_bdi_unregister()
Rename cgwb_bdi_destroy() to cgwb_bdi_unregister() as it gets called
from bdi_unregister() which is not necessarily called from bdi_destroy()
and thus the name is somewhat misleading.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Jan Kara [Thu, 23 Mar 2017 00:36:58 +0000 (01:36 +0100)]
bdi: Do not wait for cgwbs release in bdi_unregister()
Currently we wait for all cgwbs to get released in cgwb_bdi_destroy()
(called from bdi_unregister()). That is however unnecessary now when
cgwb->bdi is a proper refcounted reference (thus bdi cannot get
released before all cgwbs are released) and when cgwb_bdi_destroy()
shuts down writeback directly.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Jan Kara [Thu, 23 Mar 2017 00:36:57 +0000 (01:36 +0100)]
bdi: Shutdown writeback on all cgwbs in cgwb_bdi_destroy()
Currently we waited for all cgwbs to get freed in cgwb_bdi_destroy()
which also means that writeback has been shutdown on them. Since this
wait is going away, directly shutdown writeback on cgwbs from
cgwb_bdi_destroy() to avoid live writeback structures after
bdi_unregister() has finished. To make that safe with concurrent
shutdown from cgwb_release_workfn(), we also have to make sure
wb_shutdown() returns only after the bdi_writeback structure is really
shutdown.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Jan Kara [Thu, 23 Mar 2017 00:36:56 +0000 (01:36 +0100)]
bdi: Unify bdi->wb_list handling for root wb_writeback
Currently root wb_writeback structure is added to bdi->wb_list in
bdi_init() and never removed. That is different from all other
wb_writeback structures which get added to the list when created and
removed from it before wb_shutdown().
So move list addition of root bdi_writeback to bdi_register() and list
removal of all wb_writeback structures to wb_shutdown(). That way a
wb_writeback structure is on bdi->wb_list if and only if it can handle
writeback and it will make it easier for us to handle shutdown of all
wb_writeback structures in bdi_unregister().
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Jan Kara [Thu, 23 Mar 2017 00:36:55 +0000 (01:36 +0100)]
bdi: Make wb->bdi a proper reference
Make wb->bdi a proper refcounted reference to bdi for all bdi_writeback
structures except for the one embedded inside struct backing_dev_info.
That will allow us to simplify bdi unregistration.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Jan Kara [Thu, 23 Mar 2017 00:36:54 +0000 (01:36 +0100)]
bdi: Mark congested->bdi as internal
congested->bdi pointer is used only to be able to remove congested
structure from bdi->cgwb_congested_tree on structure release. Moreover
the pointer can become NULL when we unregister the bdi. Rename the field
to __bdi and add a comment to make it more explicit this is internal
stuff of memcg writeback code and people should not use the field as
such use will be likely race prone.
We do not bother with converting congested->bdi to a proper refcounted
reference. It will be slightly ugly to special-case bdi->wb.congested to
avoid effectively a cyclic reference of bdi to itself and the reference
gets cleared from bdi_unregister() making it impossible to reference
a freed bdi.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Jan Kara [Thu, 23 Mar 2017 00:36:53 +0000 (01:36 +0100)]
block: Fix bdi assignment to bdev inode when racing with disk delete
When disk->fops->open() in __blkdev_get() returns -ERESTARTSYS, we
restart the process of opening the block device. However we forget to
switch bdev->bd_bdi back to noop_backing_dev_info and as a result bdev
inode will be pointing to a stale bdi. Fix the problem by setting
bdev->bd_bdi later when __blkdev_get() is already guaranteed to succeed.
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Jens Axboe [Tue, 21 Mar 2017 23:20:01 +0000 (17:20 -0600)]
block: fix stacked driver stats init and free
If a driver allocates a queue for stacked usage, then it does
not currently get stats allocated. This causes the later init
of, eg, writeback throttling to blow up. Move the init to the
queue allocation instead.
Additionally, allow a NULL callback unregistration. This avoids
having the caller check for that, fixing another oops on
removal of a block device that doesn't have poll stats allocated.
Fixes: 34dbad5d26e2 ("blk-stat: convert to callback-based statistics reporting")
Signed-off-by: Jens Axboe <axboe@fb.com>
Omar Sandoval [Tue, 21 Mar 2017 15:56:08 +0000 (08:56 -0700)]
blk-stat: convert to callback-based statistics reporting
Currently, statistics are gathered in ~0.13s windows, and users grab the
statistics whenever they need them. This is not ideal for both in-tree
users:
1. Writeback throttling wants its own dynamically sized window of
statistics. Since the blk-stats statistics are reset after every
window and the wbt windows don't line up with the blk-stats windows,
wbt doesn't see every I/O.
2. Polling currently grabs the statistics on every I/O. Again, depending
on how the window lines up, we may miss some I/Os. It's also
unnecessary overhead to get the statistics on every I/O; the hybrid
polling heuristic would be just as happy with the statistics from the
previous full window.
This reworks the blk-stats infrastructure to be callback-based: users
register a callback that they want called at a given time with all of
the statistics from the window during which the callback was active.
Users can dynamically bucketize the statistics. wbt and polling both
currently use read vs. write, but polling can be extended to further
subdivide based on request size.
The callbacks are kept on an RCU list, and each callback has percpu
stats buffers. There will only be a few users, so the overhead on the
I/O completion side is low. The stats flushing is also simplified
considerably: since the timer function is responsible for clearing the
statistics, we don't have to worry about stale statistics.
wbt is a trivial conversion. After the conversion, the windowing problem
mentioned above is fixed.
For polling, we register an extra callback that caches the previous
window's statistics in the struct request_queue for the hybrid polling
heuristic to use.
Since we no longer have a single stats buffer for the request queue,
this also removes the sysfs and debugfs stats entries. To replace those,
we add a debugfs entry for the poll statistics.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Omar Sandoval [Tue, 21 Mar 2017 15:56:07 +0000 (08:56 -0700)]
blk-stat: move BLK_RQ_STAT_BATCH definition to blk-stat.c
This is an implementation detail that no-one outside of blk-stat.c uses.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Omar Sandoval [Tue, 21 Mar 2017 15:56:06 +0000 (08:56 -0700)]
blk-stat: use READ and WRITE instead of BLK_STAT_{READ,WRITE}
The stats buckets will become generic soon, so make the existing users
use the common READ and WRITE definitions instead of one internal to
blk-stat.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Omar Sandoval [Tue, 21 Mar 2017 15:56:05 +0000 (08:56 -0700)]
block: remove extra calls to wbt_exit()
We always call wbt_exit() from blk_release_queue(), so these are
unnecessary.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Omar Sandoval [Thu, 16 Mar 2017 15:46:14 +0000 (09:46 -0600)]
blk-stat: fix blk_stat_sum() if all samples are batched
We need to flush the batch _before_ we check the number of samples,
otherwise we'll miss all of the batched samples.
Fixes: cf43e6b ("block: add scalable completion tracking of requests")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Linus Torvalds [Mon, 20 Mar 2017 02:09:39 +0000 (19:09 -0700)]
Linux 4.11-rc3
Linus Torvalds [Mon, 20 Mar 2017 02:00:47 +0000 (19:00 -0700)]
mm/swap: don't BUG_ON() due to uninitialized swap slot cache
This BUG_ON() triggered for me once at shutdown, and I don't see a
reason for the check. The code correctly checks whether the swap slot
cache is usable or not, so an uninitialized swap slot cache is not
actually problematic afaik.
I've temporarily just switched the BUG_ON() to a WARN_ON_ONCE(), since
I'm not sure why that seemingly pointless check was there. I suspect
the real fix is to just remove it entirely, but for now we'll warn about
it but not bring the machine down.
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds [Mon, 20 Mar 2017 01:49:28 +0000 (18:49 -0700)]
Merge tag 'powerpc-4.11-5' of git://git./linux/kernel/git/powerpc/linux
Pull more powerpc fixes from Michael Ellerman:
"A couple of minor powerpc fixes for 4.11:
- wire up statx() syscall
- don't print a warning on memory hotplug when HPT resizing isn't
available
Thanks to: David Gibson, Chandan Rajendra"
* tag 'powerpc-4.11-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/pseries: Don't give a warning when HPT resizing isn't available
powerpc: Wire up statx() syscall
Linus Torvalds [Mon, 20 Mar 2017 01:11:13 +0000 (18:11 -0700)]
Merge branch 'parisc-4.11-2' of git://git./linux/kernel/git/deller/parisc-linux
Pull parisc fixes from Helge Deller:
- Mikulas Patocka added support for R_PARISC_SECREL32 relocations in
modules with CONFIG_MODVERSIONS.
- Dave Anglin optimized the cache flushing for vmap ranges.
- Arvind Yadav provided a fix for a potential NULL pointer dereference
in the parisc perf code (and some code cleanups).
- I wired up the new statx system call, fixed some compiler warnings
with the access_ok() macro and fixed shutdown code to really halt a
system at shutdown instead of crashing & rebooting.
* 'parisc-4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
parisc: Fix system shutdown halt
parisc: perf: Fix potential NULL pointer dereference
parisc: Avoid compiler warnings with access_ok()
parisc: Wire up statx system call
parisc: Optimize flush_kernel_vmap_range and invalidate_kernel_vmap_range
parisc: support R_PARISC_SECREL32 relocation in modules
Linus Torvalds [Mon, 20 Mar 2017 01:06:31 +0000 (18:06 -0700)]
Merge git://git./linux/kernel/git/nab/target-pending
Pull SCSI target fixes from Nicholas Bellinger:
"The bulk of the changes are in qla2xxx target driver code to address
various issues found during Cavium/QLogic's internal testing (stable
CC's included), along with a few other stability and smaller
miscellaneous improvements.
There are also a couple of different patch sets from Mike Christie,
which have been a result of his work to use target-core ALUA logic
together with tcm-user backend driver.
Finally, a patch to address some long standing issues with
pass-through SCSI export of TYPE_TAPE + TYPE_MEDIUM_CHANGER devices,
which will make folks using physical (or virtual) magnetic tape happy"
* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (28 commits)
qla2xxx: Update driver version to 9.00.00.00-k
qla2xxx: Fix delayed response to command for loop mode/direct connect.
qla2xxx: Change scsi host lookup method.
qla2xxx: Add DebugFS node to display Port Database
qla2xxx: Use IOCB interface to submit non-critical MBX.
qla2xxx: Add async new target notification
qla2xxx: Export DIF stats via debugfs
qla2xxx: Improve T10-DIF/PI handling in driver.
qla2xxx: Allow relogin to proceed if remote login did not finish
qla2xxx: Fix sess_lock & hardware_lock lock order problem.
qla2xxx: Fix inadequate lock protection for ABTS.
qla2xxx: Fix request queue corruption.
qla2xxx: Fix memory leak for abts processing
qla2xxx: Allow vref count to timeout on vport delete.
tcmu: Convert cmd_time_out into backend device attribute
tcmu: make cmd timeout configurable
tcmu: add helper to check if dev was configured
target: fix race during implicit transition work flushes
target: allow userspace to set state to transitioning
target: fix ALUA transition timeout handling
...
Linus Torvalds [Sun, 19 Mar 2017 22:45:02 +0000 (15:45 -0700)]
Merge branch 'libnvdimm-fixes' of git://git./linux/kernel/git/nvdimm/nvdimm
Pull device-dax fixes from Dan Williams:
"The device-dax driver was not being careful to handle falling back to
smaller fault-granularity sizes.
The driver already fails fault attempts that are smaller than the
device's alignment, but it also needs to handle the cases where a
larger page mapping could be established. For simplicity of the
immediate fix the implementation just signals VM_FAULT_FALLBACK until
fault-size == device-alignment.
One fix is for -stable to address pmd-to-pte fallback from the
original implementation, another fix is for the new (introduced in
4.11-rc1) pud-to-pmd regression, and a typo fix comes along for the
ride.
These have received a build success notification from the kbuild
robot"
* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
device-dax: fix debug output typo
device-dax: fix pud fault fallback handling
device-dax: fix pmd/pte fault fallback handling
Himanshu Madhani [Wed, 15 Mar 2017 16:48:56 +0000 (09:48 -0700)]
qla2xxx: Update driver version to 9.00.00.00-k
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
signed-off-by: Giridhar Malavali <giridhar.malavali@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Quinn Tran [Wed, 15 Mar 2017 16:48:55 +0000 (09:48 -0700)]
qla2xxx: Fix delayed response to command for loop mode/direct connect.
Current driver wait for FW to be in the ready state before
processing in-coming commands. For Arbitrated Loop or
Point-to- Point (not switch), FW Ready state can take a while.
FW will transition to ready state after all Nports have been
logged in. In the mean time, certain initiators have completed
the login and starts IO. Driver needs to start processing all
queues if FW is already started.
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Quinn Tran [Wed, 15 Mar 2017 16:48:54 +0000 (09:48 -0700)]
qla2xxx: Change scsi host lookup method.
For target mode, when new scsi command arrive, driver first performs
a look up of the SCSI Host. The current look up method is based on
the ALPA portion of the NPort ID. For Cisco switch, the ALPA can
not be used as the index. Instead, the new search method is based
on the full value of the Nport_ID via btree lib.
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Himanshu Madhani [Wed, 15 Mar 2017 16:48:53 +0000 (09:48 -0700)]
qla2xxx: Add DebugFS node to display Port Database
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Giridhar Malavali <giridhar.malavali@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Quinn Tran [Wed, 15 Mar 2017 16:48:52 +0000 (09:48 -0700)]
qla2xxx: Use IOCB interface to submit non-critical MBX.
The Mailbox interface is currently over subscribed. We like
to reserve the Mailbox interface for the chip managment and
link initialization. Any non essential Mailbox command will
be routed through the IOCB interface. The IOCB interface is
able to absorb more commands.
Following commands are being routed through IOCB interface
- Get ID List (007Ch)
- Get Port DB (0064h)
- Get Link Priv Stats (006Dh)
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Quinn Tran [Wed, 15 Mar 2017 16:48:51 +0000 (09:48 -0700)]
qla2xxx: Add async new target notification
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Anil Gurumurthy [Wed, 15 Mar 2017 16:48:50 +0000 (09:48 -0700)]
qla2xxx: Export DIF stats via debugfs
Signed-off-by: Anil Gurumurthy <anil.gurumurthy@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Quinn Tran [Wed, 15 Mar 2017 16:48:49 +0000 (09:48 -0700)]
qla2xxx: Improve T10-DIF/PI handling in driver.
Add routines to support T10 DIF tag.
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Anil Gurumurthy <anil.gurumurthy@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Quinn Tran [Wed, 15 Mar 2017 16:48:48 +0000 (09:48 -0700)]
qla2xxx: Allow relogin to proceed if remote login did not finish
If the remote port have started the login process, then the
PLOGI and PRLI should be back to back. Driver will allow
the remote port to complete the process. For the case where
the remote port decide to back off from sending PRLI, this
local port sets an expiration timer for the PRLI. Once the
expiration time passes, the relogin retry logic is allowed
to go through and perform login with the remote port.
Signed-off-by: Quinn Tran <quinn.tran@qlogic.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Quinn Tran [Wed, 15 Mar 2017 16:48:47 +0000 (09:48 -0700)]
qla2xxx: Fix sess_lock & hardware_lock lock order problem.
The main lock that needs to be held for CMD or TMR submission
to upper layer is the sess_lock. The sess_lock is used to
serialize cmd submission and session deletion. The addition
of hardware_lock being held is not necessary. This patch removes
hardware_lock dependency from CMD/TMR submission.
Use hardware_lock only for error response in this case.
Path1
CPU0 CPU1
---- ----
lock(&(&ha->tgt.sess_lock)->rlock);
lock(&(&ha->hardware_lock)->rlock);
lock(&(&ha->tgt.sess_lock)->rlock);
lock(&(&ha->hardware_lock)->rlock);
Path2/deadlock
*** DEADLOCK ***
Call Trace:
dump_stack+0x85/0xc2
print_circular_bug+0x1e3/0x250
__lock_acquire+0x1425/0x1620
lock_acquire+0xbf/0x210
_raw_spin_lock_irqsave+0x53/0x70
qlt_sess_work_fn+0x21d/0x480 [qla2xxx]
process_one_work+0x1f4/0x6e0
Cc: <stable@vger.kernel.org>
Cc: Bart Van Assche <Bart.VanAssche@sandisk.com>
Reported-by: Bart Van Assche <Bart.VanAssche@sandisk.com>
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Quinn Tran [Wed, 15 Mar 2017 16:48:46 +0000 (09:48 -0700)]
qla2xxx: Fix inadequate lock protection for ABTS.
Normally, ABTS is sent to Target Core as Task MGMT command.
In the case of error, qla2xxx needs to send response, hardware_lock
is required to prevent request queue corruption.
Cc: <stable@vger.kernel.org>
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Quinn Tran [Wed, 15 Mar 2017 16:48:45 +0000 (09:48 -0700)]
qla2xxx: Fix request queue corruption.
When FW notify driver or driver detects low FW resource,
driver tries to send out Busy SCSI Status to tell Initiator
side to back off. During the send process, the lock was not held.
Cc: <stable@vger.kernel.org>
Signed-off-by: Quinn Tran <quinn.tran@qlogic.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Quinn Tran [Wed, 15 Mar 2017 16:48:44 +0000 (09:48 -0700)]
qla2xxx: Fix memory leak for abts processing
Cc: <stable@vger.kernel.org>
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Joe Carnuccio [Wed, 15 Mar 2017 16:48:43 +0000 (09:48 -0700)]
qla2xxx: Allow vref count to timeout on vport delete.
Cc: <stable@vger.kernel.org>
Signed-off-by: Joe Carnuccio <joe.carnuccio@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Nicholas Bellinger [Sat, 18 Mar 2017 22:04:13 +0000 (15:04 -0700)]
tcmu: Convert cmd_time_out into backend device attribute
Instead of putting cmd_time_out under ../target/core/user_0/foo/control,
which has historically been used by parameters needed for initial
backend device configuration, go ahead and move cmd_time_out into
a backend device attribute.
In order to do this, tcmu_module_init() has been updated to create
a local struct configfs_attribute **tcmu_attrs, that is based upon
the existing passthrough_attrib_attrs along with the new cmd_time_out
attribute. Once **tcm_attrs has been setup, go ahead and point
it at tcmu_ops->tb_dev_attrib_attrs so it's picked up by target-core.
Also following MNC's previous change, ->cmd_time_out is stored in
milliseconds but exposed via configfs in seconds. Also, note this
patch restricts the modification of ->cmd_time_out to before +
after the TCMU device has been configured, but not while it has
active fabric exports.
Cc: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Mike Christie [Thu, 9 Mar 2017 08:42:09 +0000 (02:42 -0600)]
tcmu: make cmd timeout configurable
A single daemon could implement multiple types of devices
using multuple types of real devices that may not support
restarting from crashes and/or handling tcmu timeouts. This
makes the cmd timeout configurable, so handlers that do not
support it can turn if off for now.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Mike Christie [Thu, 9 Mar 2017 08:42:08 +0000 (02:42 -0600)]
tcmu: add helper to check if dev was configured
This adds a helper to check if the dev was configured. It
will be used in the next patch to prevent updates to some
config settings after the device has been setup.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Linus Torvalds [Sat, 18 Mar 2017 22:50:39 +0000 (15:50 -0700)]
Merge tag 'openrisc-for-linus' of git://github.com/openrisc/linux
Pull OpenRISC fixes from Stafford Horne:
"OpenRISC fixes for build issues that were exposed by kbuild robots
after 4.11 merge. All from allmodconfig builds. This includes:
- bug in the handling of 8-byte get_user() calls
- module build failure due to multile missing symbol exports"
* tag 'openrisc-for-linus' of git://github.com/openrisc/linux:
openrisc: Export symbols needed by modules
openrisc: fix issue handling 8 byte get_user calls
openrisc: xchg: fix `computed is not used` warning
Mike Christie [Thu, 2 Mar 2017 10:59:50 +0000 (04:59 -0600)]
target: fix race during implicit transition work flushes
This fixes the following races:
1. core_alua_do_transition_tg_pt could have read
tg_pt_gp_alua_access_state and gone into this if chunk:
if (!explicit &&
atomic_read(&tg_pt_gp->tg_pt_gp_alua_access_state) ==
ALUA_ACCESS_STATE_TRANSITION) {
and then core_alua_do_transition_tg_pt_work could update the
state. core_alua_do_transition_tg_pt would then only set
tg_pt_gp_alua_pending_state and the tg_pt_gp_alua_access_state would
not get updated with the second calls state.
2. core_alua_do_transition_tg_pt could be setting
tg_pt_gp_transition_complete while the tg_pt_gp_transition_work
is already completing. core_alua_do_transition_tg_pt then waits on the
completion that will never be called.
To handle these issues, we just call flush_work which will return when
core_alua_do_transition_tg_pt_work has completed so there is no need
to do the complete/wait. And, if core_alua_do_transition_tg_pt_work
was running, instead of trying to sneak in the state change, we just
schedule up another core_alua_do_transition_tg_pt_work call.
Note that this does not handle a possible race where there are multiple
threads call core_alua_do_transition_tg_pt at the same time. I think
we need a mutex in target_tg_pt_gp_alua_access_state_store.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Mike Christie [Thu, 2 Mar 2017 10:59:49 +0000 (04:59 -0600)]
target: allow userspace to set state to transitioning
Userspace target_core_user handlers like tcmu-runner may want to set the
ALUA state to transitioning while it does implicit transitions. This
patch allows that state when set from configfs.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Mike Christie [Thu, 2 Mar 2017 10:59:48 +0000 (04:59 -0600)]
target: fix ALUA transition timeout handling
The implicit transition time tells initiators the min time
to wait before timing out a transition. We currently schedule
the transition to occur in tg_pt_gp_implicit_trans_secs
seconds so there is no room for delays. If
core_alua_do_transition_tg_pt_work->core_alua_update_tpg_primary_metadata
needs to write out info to a remote file, then the initiator can
easily time out the operation.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Mike Christie [Thu, 2 Mar 2017 05:13:26 +0000 (23:13 -0600)]
target: Use system workqueue for ALUA transitions
If tcmu-runner is processing a STPG and needs to change the kernel's
ALUA state then we cannot use the same work queue for task management
requests and ALUA transitions, because we could deadlock. The problem
occurs when a STPG times out before tcmu-runner is able to
call into target_tg_pt_gp_alua_access_state_store->
core_alua_do_port_transition -> core_alua_do_transition_tg_pt ->
queue_work. In this case, the tmr is on the work queue waiting for
the STPG to complete, but the STPG transition is now queued behind
the waiting tmr.
Note:
This bug will also be fixed by this patch:
http://www.spinics.net/lists/target-devel/msg14560.html
which switches the tmr code to use the system workqueues.
For both, I am not sure if we need a dedicated workqueue since
it is not a performance path and I do not think we need WQ_MEM_RECLAIM
to make forward progress to free up memory like the block layer does.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Mike Christie [Thu, 2 Mar 2017 05:13:25 +0000 (23:13 -0600)]
target: fail ALUA transitions for pscsi
We do not setup the LU group for pscsi devices, so if you write
a state to alua_access_state that will cause a transition you will
get a NULL pointer dereference.
This patch will fail attempts to try and transition the path
for backend devices that set the TRANSPORT_FLAG_PASSTHROUGH_ALUA
flag.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Mike Christie [Thu, 2 Mar 2017 05:13:24 +0000 (23:13 -0600)]
target: allow ALUA setup for some passthrough backends
This patch allows passthrough backends to use the core/base LIO
ALUA setup and state checks, but still handle the execution of
commands.
This will allow the target_core_user module to execute STPG and RTPG
in userspace, and not have to duplicate the ALUA state checks, path
information (needed so we can check if command is executable on
specific paths) and setup (rtslib sets/updates the configfs ALUA
interface like it does for iblock or file).
For STPG, the target_core_user userspace daemon, tcmu-runner will
still execute the STPG, and to update the core/base LIO state it
will use the existing configfs interface. For RTPG, tcmu-runner
will loop over configfs and/or cache the state.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Mike Christie [Thu, 2 Mar 2017 05:14:40 +0000 (23:14 -0600)]
tcmu: return on first Opt parse failure
We only were returing failure if the last opt to be parsed failed.
This has a return failure when we first detect a failure.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Mike Christie [Thu, 2 Mar 2017 05:14:39 +0000 (23:14 -0600)]
tcmu: allow hw_max_sectors greater than 128
tcmu hard codes the hw_max_sectors to 128 which is a litle small.
Userspace uses the max_sectors to report the optimal IO size and
some initiators perform better with larger IOs (open-iscsi seems
to do better with 256 to 512 depending on the test).
(Fix do not display hw max sectors twice - MNC)
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Nicholas Bellinger [Wed, 8 Mar 2017 08:09:59 +0000 (00:09 -0800)]
target: Drop pointless tfo->check_stop_free check
All in-tree fabric drivers provide a tfo->check_stop_free(),
so there is no need to do the extra check within existing
transport_cmd_check_stop_to_fabric() code.
Just to be sure, add a check in target_fabric_tf_ops_check()
to notify any out-of-tree drivers that might be missing it.
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>