linux.git/block/blk.h, branch v4.19.59

block: make sure discard bio is aligned with logical block size

2018-11-13T19:08:16+00:00

commit 1adfc5e4136f5967d591c399aff95b3b035f16b7 upstream.

Obviously the created discard bio has to be aligned with logical block size.

This patch introduces the helper of bio_allowed_max_sectors() for
this purpose.

Cc: stable@vger.kernel.org
Cc: Mike Snitzer 
Cc: Christoph Hellwig 
Cc: Xiao Ni 
Cc: Mariusz Dabrowski 
Fixes: 744889b7cbb56a6 ("block: don't deal with discard limit in blkdev_issue_discard()")
Fixes: a22c4d7e34402cc ("block: re-add discard_granularity and alignment checks")
Reported-by: Rui Salvaterra 
Tested-by: Rui Salvaterra 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

blk-mq: init hctx sched after update ctx and hctx mapping

2018-08-21T15:02:55+00:00

Currently, when update nr_hw_queues, IO scheduler's init_hctx will
be invoked before the mapping between ctx and hctx is adapted
correctly by blk_mq_map_swqueue. The IO scheduler init_hctx (kyber)
may depend on this mapping and get wrong result and panic finally.
A simply way to fix this is that switch the IO scheduler to 'none'
before update the nr_hw_queues, and then switch it back after
update nr_hw_queues. blk_mq_sched_init_/exit_hctx are removed due
to nobody use them any more.

Signed-off-by: Jianchao Wang 
Signed-off-by: Jens Axboe

block: change return type to bool

2018-08-16T19:44:17+00:00

Because blk_do_io_stat() only does a judgement about the request
contributes to IO statistics, it better changes return type to bool.

Signed-off-by: Chengguang Xu 
Signed-off-by: Jens Axboe

block: Introduce blk_exit_queue()

2018-08-09T15:12:59+00:00

This patch does not change any functionality.

Signed-off-by: Bart Van Assche 
Reviewed-by: Johannes Thumshirn 
Cc: Christoph Hellwig 
Cc: Ming Lei 
Cc: Omar Sandoval 
Cc: Alexandru Moise <00moses.alexander00@gmail.com>
Cc: Joseph Qi 
Cc: 
Signed-off-by: Jens Axboe

block: introduce blk-iolatency io controller

2018-07-09T15:07:54+00:00

Current IO controllers for the block layer are less than ideal for our
use case.  The io.max controller is great at hard limiting, but it is
not work conserving.  This patch introduces io.latency.  You provide a
latency target for your group and we monitor the io in short windows to
make sure we are not exceeding those latency targets.  This makes use of
the rq-qos infrastructure and works much like the wbt stuff.  There are
a few differences from wbt

 - It's bio based, so the latency covers the whole block layer in addition to
   the actual io.
 - We will throttle all IO types that comes in here if we need to.
 - We use the mean latency over the 100ms window.  This is because writes can
   be particularly fast, which could give us a false sense of the impact of
   other workloads on our protected workload.
 - By default there's no throttling, we set the queue_depth to INT_MAX so that
   we can have as many outstanding bio's as we're allowed to.  Only at
   throttle time do we pay attention to the actual queue depth.
 - We backcharge cgroups for root cg issued IO and induce artificial
   delays in order to deal with cases like metadata only or swap heavy
   workloads.

In testing this has worked out relatively well.  Protected workloads
will throttle noisy workloads down to 1 io at time if they are doing
normal IO on their own, or induce up to a 1 second delay per syscall if
they are doing a lot of root issued IO (metadata/swap IO).

Our testing has revolved mostly around our production web servers where
we have hhvm (the web server application) in a protected group and
everything else in another group.  We see slightly higher requests per
second (RPS) on the test tier vs the control tier, and much more stable
RPS across all machines in the test tier vs the control tier.

Another test we run is a slow memory allocator in the unprotected group.
Before this would eventually push us into swap and cause the whole box
to die and not recover at all.  With these patches we see slight RPS
drops (usually 10-15%) before the memory consumer is properly killed and
things recover within seconds.

Signed-off-by: Josef Bacik 
Acked-by: Tejun Heo 
Signed-off-by: Jens Axboe

block: split the blk-mq case from elevator_init

2018-06-01T13:38:21+00:00

There is almost no shared logic, which leads to a very confusing code
flow.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Tested-by: Damien Le Moal 
Signed-off-by: Jens Axboe

block: remove the always unused name argument to elevator_init

2018-06-01T13:38:17+00:00

Reported-by: Damien Le Moal 
Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Tested-by: Damien Le Moal 
Signed-off-by: Jens Axboe

block: unexport elevator_init/exit

2018-06-01T13:38:16+00:00

These are only used by the block core.  Also move the declarations to
block/blk.h.

Reported-by: Damien Le Moal 
Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Tested-by: Damien Le Moal 
Signed-off-by: Jens Axboe

block: consolidate struct request timestamp fields

2018-05-09T14:33:09+00:00

Currently, struct request has four timestamp fields:

- A start time, set at get_request time, in jiffies, used for iostats
- An I/O start time, set at start_request time, in ktime nanoseconds,
  used for blk-stats (i.e., wbt, kyber, hybrid polling)
- Another start time and another I/O start time, used for cfq and bfq

These can all be consolidated into one start time and one I/O start
time, both in ktime nanoseconds, shaving off up to 16 bytes from struct
request depending on the kernel config.

Signed-off-by: Omar Sandoval 
Signed-off-by: Jens Axboe

block: Move the queue_flag_*() functions from a public into a private header file

2018-03-08T21:13:48+00:00

This patch helps to avoid that new code gets introduced in block drivers
that manipulates queue flags without holding the queue lock when that
lock should be held.

Cc: Christoph Hellwig 
Cc: Hannes Reinecke 
Cc: Ming Lei 
Reviewed-by: Johannes Thumshirn 
Reviewed-by: Martin K. Petersen 
Signed-off-by: Bart Van Assche 
Signed-off-by: Jens Axboe