Damien Le Moal [Thu, 21 Dec 2017 06:43:44 +0000 (15:43 +0900)]
scsi: sd: Remove zone write locking
The block layer now handles zone write locking.
[mkp: removed SCMD_ZONE_WRITE_LOCK reference in scsi_debugfs]
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Damien Le Moal [Thu, 21 Dec 2017 06:43:43 +0000 (15:43 +0900)]
scsi: sd_zbc: Initialize device request queue zoned data
Initialize the seq_zones_bitmap, seq_zones_wlock and nr_zones fields of
the disk request queue on disk revalidate. As the seq_zones_bitmap and
seq_zones_wlock allocations are identical, introduce the helper
sd_zbc_alloc_zone_bitmap(). Using this helper, reallocate the bitmaps
whenever the disk capacity (number of zones) changes.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Bart Van Assche [Wed, 6 Dec 2017 00:57:53 +0000 (16:57 -0800)]
scsi: scsi-mq-debugfs: Show more information
Show the request result, request timeout and SCSI command flags. This
information is very helpful when trying to figure out why a queue got
stuck. An example of the information that is exported through debugfs:
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: James E.J. Bottomley <jejb@linux.vnet.ibm.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Ming Lei <ming.lei@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Israel Rukshin [Thu, 4 Jan 2018 15:56:14 +0000 (17:56 +0200)]
nvme: fix subsystem multiple controllers support check
There is a problem when another module (e.g. nvmet) takes a reference on
the nvme block device and the physical nvme drive is removed. In that
case nvme_free_ctrl() will not be called and the controller state will be
"deleting" or "dead" unless nvmet module releases the block device.
Later on, the same nvme drive probes back and nvme_init_subsystem() will
be called and fail due to duplicate subnqn (if the nvme device doesn't
support subsystem with multiple controllers). This will cause a probe
failure. This commit changes the check of multiple controllers support
at nvme_init_subsystem() by not counting all the controllers at "dead" or
"deleting" state (this is safe because controllers at this state will
never be active again).
Fixes: ab9e00cc72fa ("nvme: track subsystems") Reviewed-by: Max Gurtovoy <maxg@mellanox.com> Signed-off-by: Israel Rukshin <israelr@mellanox.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Nitzan Carmi [Thu, 4 Jan 2018 15:56:13 +0000 (17:56 +0200)]
nvme: take refcount on transport module
The block device is backed by the transport so we must ensure that the
transport driver will not be removed until all references are released.
Otherwise, we might end up referencing freed memory.
Reviewed-by: Max Gurtovoy <maxg@mellanox.com> Signed-off-by: Nitzan Carmi <nitzanc@mellanox.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Jianchao Wang [Sat, 6 Jan 2018 00:01:58 +0000 (08:01 +0800)]
nvme-pci: fix NULL pointer reference in nvme_alloc_ns
When the io queues setup or tagset allocation failed, ctrl.tagset is
NULL. But the scan work will still be queued and executed, then panic
comes up due to NULL pointer reference of ctrl.tagset.
To fix this, add a new ctrl state NVME_CTRL_ADMIN_ONLY to inidcate only
admin queue is live. When non io queues or tagset allocation failed, ctrl
enters into this state, scan work will not be started. But async event
work and nvme dev ioctl will be still available. This will be helpful to
do further investigation and recovery.
Suggested-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Max Gurtovoy [Sun, 31 Dec 2017 13:33:27 +0000 (15:33 +0200)]
nvme: modify the debug level for setting shutdown timeout
When an NVMe controller reports RTD3 Entry Latency larger than the value
of shutdown_timeout module parameter, we update the shutdown_timeout
accordingly to honor RTD3 Entry Latency. Use an informational debug level
instead of a warning level for it.
Signed-off-by: Max Gurtovoy <maxg@mellanox.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Roy Shterman [Mon, 25 Dec 2017 12:18:30 +0000 (14:18 +0200)]
nvme-fabrics: protect against module unload during create_ctrl
NVMe transport driver module unload may (and usually does) trigger
iteration over the active controllers and delete them all (sometimes
under a mutex). However, a controller can be created concurrently with
module unload which can lead to leakage of resources (most important char
device node leakage) in case the controller creation occured after the
unload delete and drain sequence. To protect against this, we take a
module reference to guarantee that the nvme transport driver is not
unloaded while creating a controller.
Signed-off-by: Roy Shterman <roys@lightbitslabs.com> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Max Gurtovoy <maxg@mellanox.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
James Smart [Wed, 29 Nov 2017 23:11:55 +0000 (15:11 -0800)]
nvmet-fc: cleanup nvmet add_port/remove_port
The current fc transport add_port routine validates that there is a
matching port to the target port config. It then takes a reference
on the targetport. The del_port removes the reference.
Unfortunately, if the LLDD undergoes a hw reset or driver unload and
wants to unreg the targetport, due to the reference, the targetport
effectively can't be removed. It requires the admin to remove the
port from the nvmet config first, which calls the del_port.
Note: it appears nvmetcli clear skips over the del_port call (I'm
not attempting to change that).
There's no real reason to take the reference. With FC, there is nothing
to enable or disable as the presence of the FC targetport implicitly
means its enabled, and removal of the targtport means its disabled.
Change add_port to simply validate and change remove_port to a noop.
No references are taken on the targetport.
Signed-off-by: James Smart <james.smart@broadcom.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
James Smart [Thu, 30 Nov 2017 00:47:33 +0000 (16:47 -0800)]
nvme_fcloop: refactor host/target io job access
The split between what the host accesses on its flows vs what the
target side accesses was flawed. Abort handling didn't properly
clear initiator vs target structure cross-reference and locks
weren't used for synchronization. Thus, there were issues of
freeing structures too soon and access after free.
A couple of these existed pre the IN_ISR mods, but when the
target upcalls were converted to work items, thus adding delays
between the 2 sides of accesses, the problems became pronounced.
Resolve by:
- tracking io state mainly in the tgt-side io structure.
- make the tgt-side io structure released by reference not by
code flow.
- when changing initiator structures, use locks for
synchronization
- aborts are clearly tracked for which side saw the abort, and
after seeing the abort, cross-references are cleared under lock.
Signed-off-by: James Smart <james.smart@broadcom.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
James Smart [Thu, 30 Nov 2017 00:47:32 +0000 (16:47 -0800)]
nvme_fcloop: rework to remove xxx_IN_ISR feature flags
The existing fcloop driver expects the target side upcalls to
the transport to context switch, thus the calls into the nvmet layer
are not done in the calling context of the host/initiator down calls.
The xxx_IN_ISR feature flags are used to select this logic.
The xxx_IN_ISR feature flags should go away in the nvmet_fc transport
as no other lldd utilizes them. Both Broadcom and Cavium lldds have their
own non-ISR deferred handlers thus the nvmet calls can be made directly.
This patch converts the paths that make the target upcalls (command
receive, abort receive) such that they schedule a work item rather
than expecting the transport to schedule the work item.
The patch also cleans up the following:
- The completion path from target to host scheduled a host work
element called "work". Rename it "tio_done_work" for code clarity.
- The abort io path called a iniwork item to call the host side
io done. This is no longer needed as the abort routine can make
the same call.
Signed-off-by: James Smart <james.smart@broadcom.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
James Smart [Thu, 30 Nov 2017 00:47:31 +0000 (16:47 -0800)]
nvme_fcloop: disassocate local port structs
The current fcloop driver gets its lport structure from the private
area co-allocated with the fc_localport. All is fine except the
teardown path, which wants to wait on the completion, which is marked
complete by the delete_localport callback performed after
unregister_localport. The issue is, the nvme_fc transport frees the
localport structure immediately after delete_localport is called,
meaning the original routine is trying to wait on a complete that
was just freed.
Change such that a lport struct is allocated coincident with the
addition and registration of a localport. The private area of the
localport now contains just a backpointer to the real lport struct.
Now, the completion can be waited for, and after completing, the
new structure can be kfree'd.
Signed-off-by: James Smart <james.smart@broadcom.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
James Smart [Thu, 30 Nov 2017 00:47:30 +0000 (16:47 -0800)]
nvme_fcloop: fix abort race condition
A test case revealed a race condition of an i/o completing on a thread
parallel to the delete_association generating the aborts for the
outstanding ios on the controller. The i/o completion was freeing the
target fcloop context, thus the abort task referenced the just-freed
memory.
Correct by clearing the target/initiator cross pointers in the io
completion and abort tasks before calling the callbacks. On aborts
that detect already finished io's, ensure the complete context is
called.
Signed-off-by: James Smart <james.smart@broadcom.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Ming Lei [Sat, 6 Jan 2018 08:27:40 +0000 (16:27 +0800)]
blk-mq: fix race between updating nr_hw_queues and switching io sched
In both elevator_switch_mq() and blk_mq_update_nr_hw_queues(), sched tags
can be allocated, and q->nr_hw_queue is used, and race is inevitable, for
example: blk_mq_init_sched() may trigger use-after-free on hctx, which is
freed in blk_mq_realloc_hw_ctxs() when nr_hw_queues is decreased.
This patch fixes the race be holding q->sysfs_lock.
Reviewed-by: Christoph Hellwig <hch@lst.de> Reported-by: Yi Zhang <yi.zhang@redhat.com> Tested-by: Yi Zhang <yi.zhang@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Christoph Hellwig <hch@lst.de> Suggested-by: Christoph Hellwig <hch@lst.de> Reported-by: Yi Zhang <yi.zhang@redhat.com> Tested-by: Yi Zhang <yi.zhang@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Ming Lei [Sat, 6 Jan 2018 08:27:38 +0000 (16:27 +0800)]
blk-mq: quiesce queue during switching io sched and updating nr_requests
Dispatch may still be in-progress after queue is frozen, so we have to
quiesce queue before switching IO scheduler and updating nr_requests.
Also when switching io schedulers, blk_mq_run_hw_queue() may still be
called somewhere(such as from nvme_reset_work()), and io scheduler's
per-hctx data may not be setup yet, so cause oops even inside
blk_mq_hctx_has_pending(), such as it can be run just between:
ret = e->ops.mq.init_sched(q, e);
AND
ret = e->ops.mq.init_hctx(hctx, i)
inside blk_mq_init_sched().
This reverts commit 7a148c2fcff8330(block: don't call blk_mq_quiesce_queue()
after queue is frozen) basically, and makes sure blk_mq_hctx_has_pending
won't be called if queue is quiesced.
Reviewed-by: Christoph Hellwig <hch@lst.de> Fixes: 7a148c2fcff83309(block: don't call blk_mq_quiesce_queue() after queue is frozen) Reported-by: Yi Zhang <yi.zhang@redhat.com> Tested-by: Yi Zhang <yi.zhang@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Ming Lei [Sat, 6 Jan 2018 08:27:37 +0000 (16:27 +0800)]
blk-mq: quiesce queue before freeing queue
After queue is frozen, dispatch still may happen, for example:
1) requests are submitted from several contexts
2) requests from all these contexts are inserted to queue, but may dispatch
to LLD in one of these paths, but other paths sill need to move on even all
these requests are completed(that means blk_mq_freeze_queue_wait() returns
at that time)
3) dispatch after queue freezing still moves on and causes use-after-free,
because request queue is freed
This patch quiesces queue after it is frozen, and makes sure all
in-progress dispatch are completed.
This patch fixes the following kernel crash when running heavy IOs vs.
deleting device:
Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: stable@vger.kernel.org Tested-by: Yi Zhang <yi.zhang@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Jens Axboe [Sat, 6 Jan 2018 16:23:11 +0000 (09:23 -0700)]
mq-deadline: make it clear that __dd_dispatch_request() works on all hw queues
Don't pass in the hardware queue to __dd_dispatch_request(), since it
leads the reader to believe that we are returning a request for that
specific hardware queue. That's not how mq-deadline works, the state
for determining which request to serve next is shared across all
hardware queues for a device.
Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Bart Van Assche [Fri, 5 Jan 2018 16:26:46 +0000 (08:26 -0800)]
lib/scatterlist: Introduce sgl_alloc() and sgl_free()
Many kernel drivers contain code that allocates and frees both a
scatterlist and the pages that populate that scatterlist.
Introduce functions in lib/scatterlist.c that perform these tasks
instead of duplicating this functionality in multiple drivers.
Only include these functions in the build if CONFIG_SGL_ALLOC=y
to avoid that the kernel size increases if this functionality is
not used.
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Arnd Bergmann [Mon, 11 Dec 2017 12:11:17 +0000 (13:11 +0100)]
DAC960: split up ioctl function to reduce stack size
When CONFIG_KASAN is set, all the local variables in this function are
allocated on the stack together, leading to a warning about possible
kernel stack overflow:
drivers/block/DAC960.c: In function 'DAC960_gam_ioctl':
drivers/block/DAC960.c:7061:1: error: the frame size of 2240 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
By splitting up the function into smaller chunks, we can avoid that and
make the code slightly more readable at the same time. The coding style
in this file is completely nonstandard, and I chose to not touch that
at all, leaving the unconventional intendation unchanged to make it
easier to review the diff.
Ming Lei [Mon, 18 Dec 2017 12:22:15 +0000 (20:22 +0800)]
block: blk-merge: try to make front segments in full size
When merging one bvec into segment, if the bvec is too big
to merge, current policy is to move the whole bvec into another
new segment.
This patchset changes the policy into trying to maximize size of
front segments, that means in above situation, part of bvec
is merged into current segment, and the remainder is put
into next segment.
This patch prepares for support multipage bvec because
it can be quite common to see this case and we should try
to make front segments in full size.
Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
It is enough to check and compute bio->bi_seg_front_size just
after the 1st segment is found, but current code checks that
for each bvec, which is inefficient.
This patch follows the way in __blk_recalc_rq_segments()
for computing bio->bi_seg_front_size, and it is more efficient
and code becomes more readable too.
Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Ming Lei [Mon, 18 Dec 2017 12:22:12 +0000 (20:22 +0800)]
btrfs: avoid accessing bvec table directly for a cloned bio
Commit 17347cec15f919901c90(Btrfs: change how we iterate bios in endio)
mentioned that for dio the submitted bio may be fast cloned, we
can't access the bvec table directly for a cloned bio, so use
bio_get_first_bvec() to retrieve the 1st bvec.
Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: David Sterba <dsterba@suse.com> Cc: linux-btrfs@vger.kernel.org Cc: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Acked: David Sterba <dsterba@suse.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Ming Lei [Mon, 18 Dec 2017 12:22:11 +0000 (20:22 +0800)]
btrfs: avoid access to .bi_vcnt directly
BTRFS uses bio->bi_vcnt to figure out page numbers, this approach is no
longer valid once we start enabling multipage bvecs.
correct once we start to enable multipage bvec.
Use bio_nr_pages() to do that instead.
Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: David Sterba <dsterba@suse.com> Cc: linux-btrfs@vger.kernel.org Acked-by: David Sterba <dsterba@suse.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Ming Lei [Mon, 18 Dec 2017 12:22:09 +0000 (20:22 +0800)]
bcache: comment on direct access to bvec table
All direct access to bvec table are safe even after multipage bvec is
supported.
Cc: linux-bcache@vger.kernel.org Acked-by: Coly Li <colyli@suse.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Ming Lei [Mon, 18 Dec 2017 12:22:08 +0000 (20:22 +0800)]
dm: limit the max bio size as BIO_MAX_PAGES * PAGE_SIZE
For BIO based DM, some targets aren't ready for dealing with bigger
incoming bio than 1Mbyte, such as crypt target.
Cc: Mike Snitzer <snitzer@redhat.com>
Cc:dm-devel@redhat.com Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
All are named as bio_*_all() to following bio_for_each_segment_all(),
they can only be used on bio of !bio_flagged(bio, BIO_CLONED), that means
the whole bvec table is covered.
Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Paolo Valente [Mon, 4 Dec 2017 10:42:05 +0000 (11:42 +0100)]
block, bfq: remove batches of confusing ifdefs
Commit a33801e8b473 ("block, bfq: move debug blkio stats behind
CONFIG_DEBUG_BLK_CGROUP") introduced two batches of confusing ifdefs:
one reported in [1], plus a similar one in another function. This
commit removes both batches, in the way suggested in [1].
Paolo Valente [Fri, 15 Dec 2017 06:23:12 +0000 (07:23 +0100)]
block, bfq: consider also past I/O in soft real-time detection
BFQ privileges the I/O of soft real-time applications, such as video
players, to guarantee to these application a high bandwidth and a low
latency. In this respect, it is not easy to correctly detect when an
application is soft real-time. A particularly nasty false positive is
that of an I/O-bound application that occasionally happens to meet all
requirements to be deemed as soft real-time. After being detected as
soft real-time, such an application monopolizes the device. Fortunately,
BFQ will realize soon that the application is actually not soft
real-time and suspend every privilege. Yet, the application may happen
again to be wrongly detected as soft real-time, and so on.
As highlighted by our tests, this problem causes BFQ to occasionally
fail to guarantee a high responsiveness, in the presence of heavy
background I/O workloads. The reason is that the background workload
happens to be detected as soft real-time, more or less frequently,
during the execution of the interactive task under test. To give an
idea, because of this problem, Libreoffice Writer occasionally takes 8
seconds, instead of 3, to start up, if there are sequential reads and
writes in the background, on a Kingston SSDNow V300.
This commit addresses this issue by leveraging the following facts.
The reason why some applications are detected as soft real-time despite
all BFQ checks to avoid false positives, is simply that, during high
CPU or storage-device load, I/O-bound applications may happen to do
I/O slowly enough to meet all soft real-time requirements, and pass
all BFQ extra checks. Yet, this happens only for limited time periods:
slow-speed time intervals are usually interspersed between other time
intervals during which these applications do I/O at a very high speed.
To exploit these facts, this commit introduces a little change, in the
detection of soft real-time behavior, to systematically consider also
the recent past: the higher the speed was in the recent past, the
later next I/O should arrive for the application to be considered as
soft real-time. At the beginning of a slow-speed interval, the minimum
arrival time allowed for the next I/O usually happens to still be so
high, to fall *after* the end of the slow-speed period itself. As a
consequence, the application does not risk to be deemed as soft
real-time during the slow-speed interval. Then, during the next
high-speed interval, the application cannot, evidently, be deemed as
soft real-time (exactly because of its speed), and so on.
This extra filtering proved to be rather effective: in the above test,
the frequency of false positives became so low that the start-up time
was 3 seconds in all iterations (apart from occasional outliers,
caused by page-cache-management issues, which are out of the scope of
this commit, and cannot be solved by an I/O scheduler).
Tested-by: Lee Tibbert <lee.tibbert@gmail.com> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Angelo Ruocco <angeloruocco90@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Angelo Ruocco [Wed, 20 Dec 2017 11:38:34 +0000 (12:38 +0100)]
block, bfq: remove superfluous check in queue-merging setup
When two or more processes do I/O in a way that the their requests are
sequential in respect to one another, BFQ merges the bfq_queues associated
with the processes. This way the overall I/O pattern becomes sequential,
and thus there is a boost in througput.
These cooperating processes usually start or restart to do I/O shortly
after each other. So, in order to avoid merging non-cooperating processes,
BFQ ensures that none of these queues has been in weight raising for too
long.
In this respect, from commit "block, bfq-sq, bfq-mq: let a queue be merged
only shortly after being created", BFQ checks whether any queue (and not
only weight-raised ones) is doing I/O continuously from too long to be
merged.
This new additional check makes the first one useless: a queue doing
I/O from long enough, if being weight-raised, is also a queue in
weight raising for too long to be merged. Accordingly, this commit
removes the first check.
Paolo Valente [Wed, 20 Dec 2017 11:38:33 +0000 (12:38 +0100)]
block, bfq: let a queue be merged only shortly after starting I/O
In BFQ and CFQ, two processes are said to be cooperating if they do
I/O in such a way that the union of their I/O requests yields a
sequential I/O pattern. To get such a sequential I/O pattern out of
the non-sequential pattern of each cooperating process, BFQ and CFQ
merge the queues associated with these processes. In more detail,
cooperating processes, and thus their associated queues, usually
start, or restart, to do I/O shortly after each other. This is the
case, e.g., for the I/O threads of KVM/QEMU and of the dump
utility. Basing on this assumption, this commit allows a bfq_queue to
be merged only during a short time interval (100ms) after it starts,
or re-starts, to do I/O. This filtering provides two important
benefits.
First, it greatly reduces the probability that two non-cooperating
processes have their queues merged by mistake, if they just happen to
do I/O close to each other for a short time interval. These spurious
merges cause loss of service guarantees. A low-weight bfq_queue may
unjustly get more than its expected share of the throughput: if such a
low-weight queue is merged with a high-weight queue, then the I/O for
the low-weight queue is served as if the queue had a high weight. This
may damage other high-weight queues unexpectedly. For instance,
because of this issue, lxterminal occasionally took 7.5 seconds to
start, instead of 6.5 seconds, when some sequential readers and
writers did I/O in the background on a FUJITSU MHX2300BT HDD. The
reason is that the bfq_queues associated with some of the readers or
the writers were merged with the high-weight queues of some processes
that had to do some urgent but little I/O. The readers then exploited
the inherited high weight for all or most of their I/O, during the
start-up of terminal. The filtering introduced by this commit
eliminated any outlier caused by spurious queue merges in our start-up
time tests.
This filtering also provides a little boost of the throughput
sustainable by BFQ: 3-4%, depending on the CPU. The reason is that,
once a bfq_queue cannot be merged any longer, this commit makes BFQ
stop updating the data needed to handle merging for the queue.
Angelo Ruocco [Wed, 20 Dec 2017 11:38:32 +0000 (12:38 +0100)]
block, bfq: check low_latency flag in bfq_bfqq_save_state()
A just-created bfq_queue will certainly be deemed as interactive on
the arrival of its first I/O request, if the low_latency flag is
set. Yet, if the queue is merged with another queue on the arrival of
its first I/O request, it will not have the chance to be flagged as
interactive. Nevertheless, if the queue is then split soon enough, it
has to be flagged as interactive after the split.
To handle this early-merge scenario correctly, BFQ saves the state of
the queue, on the merge, as if the latter had already been deemed
interactive. So, if the queue is split soon, it will get
weight-raised, because the previous state of the queue is resumed on
the split.
Unfortunately, in the act of saving the state of the newly-created
queue, BFQ doesn't check whether the low_latency flag is set, and this
causes early-merged queues to be then weight-raised, on queue splits,
even if low_latency is off. This commit addresses this problem by
adding the missing check.
Paolo Valente [Wed, 20 Dec 2017 11:38:31 +0000 (12:38 +0100)]
block, bfq: add missing rq_pos_tree update on rq removal
If two processes do I/O close to each other, then BFQ merges the
bfq_queues associated with these processes, to get a more sequential
I/O, and thus a higher throughput. In this respect, to detect whether
two processes are doing I/O close to each other, BFQ keeps a list of
the head-of-line I/O requests of all active bfq_queues. The list is
ordered by initial sectors, and implemented through a red-black tree
(rq_pos_tree).
Unfortunately, the update of the rq_pos_tree was incomplete, because
the tree was not updated on the removal of the head-of-line I/O
request of a bfq_queue, in case the queue did not remain empty. This
commit adds the missing update.
Paolo Valente [Wed, 20 Dec 2017 16:27:36 +0000 (17:27 +0100)]
block, bfq: increase threshold to deem I/O as random
If two processes do I/O close to each other, i.e., are cooperating
processes in BFQ (and CFQ'S) nomenclature, then BFQ merges their
associated bfq_queues, so as to get sequential I/O from the union of
the I/O requests of the processes, and thus reach a higher
throughput. A merged queue is then split if its I/O stops being
sequential. In this respect, BFQ deems the I/O of a bfq_queue as
(mostly) sequential only if less than 4 I/O requests are random, out
of the last 32 requests inserted into the queue.
Unfortunately, extensive testing (with the interleaved_io benchmark of
the S suite [1], and with real applications spawning cooperating
processes) has clearly shown that, with such a low threshold, only a
rather low I/O throughput may be reached when several cooperating
processes do I/O. In particular, the outcome of each test run was
bimodal: if queue merging occurred and was stable during the test,
then the throughput was close to the peak rate of the storage device,
otherwise the throughput was arbitrarily low (usually around 1/10 of
the peak rate with a rotational device). The probability to get the
unlucky outcomes grew with the number of cooperating processes: it was
already significant with 5 processes, and close to one with 7 or more
processes.
The cause of the low throughput in the unlucky runs was that the
merged queues containing the I/O of these cooperating processes were
soon split, because they contained more random I/O requests than those
tolerated by the 4/32 threshold, but
- that I/O would have however allowed the storage device to reach
peak throughput or almost peak throughput;
- in contrast, the I/O of these processes, if served individually
(from separate queues) yielded a rather low throughput.
So we repeated our tests with increasing values of the threshold,
until we found the minimum value (19) for which we obtained maximum
throughput, reliably, with at least up to 9 cooperating
processes. Then we checked that the use of that higher threshold value
did not cause any regression for any other benchmark in the suite [1].
This commit raises the threshold to such a higher value.
Damien Le Moal [Thu, 21 Dec 2017 06:43:42 +0000 (15:43 +0900)]
deadline-iosched: Introduce zone locking support
Introduce zone write locking to avoid write request reordering with
zoned block devices. This is achieved using a finer selection of the
next request to dispatch:
1) Any non-write request is always allowed to proceed.
2) Any write to a conventional zone is always allowed to proceed.
3) For a write to a sequential zone, the zone lock is first checked.
a) If the zone is not locked, the write is allowed to proceed after
its target zone is locked.
b) If the zone is locked, the write request is skipped and the next
request in the dispatch queue tested (back to step 1).
For a write request that has locked its target zone, the zone is
unlocked either when the request completes and the method
deadline_request_completed() is called, or when the request is requeued
using the method deadline_add_request().
Requests targeting a locked zone are always left in the scheduler queue
to preserve the initial write order. If no write request can be
dispatched, allow reads to be dispatched even if the write batch is not
done.
If the device used is not a zoned block device, or if zoned block device
support is disabled, this patch does not modify deadline behavior.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Damien Le Moal [Thu, 21 Dec 2017 06:43:41 +0000 (15:43 +0900)]
deadline-iosched: Introduce dispatch helpers
Avoid directly referencing the next_rq and fifo_list arrays using the
helper functions deadline_next_request() and deadline_fifo_request() to
facilitate changes in the dispatch request selection in
deadline_dispatch_requests() for zoned block devices.
While at it, also remove the unnecessary forward declaration of the
function deadline_move_request().
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Damien Le Moal [Thu, 21 Dec 2017 06:43:40 +0000 (15:43 +0900)]
mq-deadline: Introduce zone locking support
Introduce zone write locking to avoid write request reordering with
zoned block devices. This is achieved using a finer selection of the
next request to dispatch:
1) Any non-write request is always allowed to proceed.
2) Any write to a conventional zone is always allowed to proceed.
3) For a write to a sequential zone, the zone lock is first checked.
a) If the zone is not locked, the write is allowed to proceed after
its target zone is locked.
b) If the zone is locked, the write request is skipped and the next
request in the dispatch queue tested (back to step 1).
For a write request that has locked its target zone, the zone is
unlocked either when the request completes with a call to the method
deadline_request_completed() or when the request is requeued using
dd_insert_request().
Requests targeting a locked zone are always left in the scheduler queue
to preserve the lba ordering for write requests. If no write request
can be dispatched, allow reads to be dispatched even if the write batch
is not done.
If the device used is not a zoned block device, or if zoned block device
support is disabled, this patch does not modify mq-deadline behavior.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Damien Le Moal [Thu, 21 Dec 2017 06:43:39 +0000 (15:43 +0900)]
mq-deadline: Introduce dispatch helpers
Avoid directly referencing the next_rq and fifo_list arrays using the
helper functions deadline_next_request() and deadline_fifo_request() to
facilitate changes in the dispatch request selection in
__dd_dispatch_request() for zoned block devices.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Bart Van Assche <Bart.VanAssche@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
block: introduce zoned block devices zone write locking
Components relying only on the request_queue structure for accessing
block devices (e.g. I/O schedulers) have a limited knowledged of the
device characteristics. In particular, the device capacity cannot be
easily discovered, which for a zoned block device also result in the
inability to easily know the number of zones of the device (the zone
size is indicated by the chunk_sectors field of the queue limits).
Introduce the nr_zones field to the request_queue structure to simplify
access to this information. Also, add the bitmap seq_zone_bitmap which
indicates which zones of the device are sequential zones (write
preferred or write required) and the bitmap seq_zones_wlock which
indicates if a zone is write locked, that is, if a write request
targeting a zone was dispatched to the device. These fields are
initialized by the low level block device driver (sd.c for ZBC/ZAC
disks). They are not initialized by stacking drivers (device mappers)
handling zoned block devices (e.g. dm-linear).
Using this, I/O schedulers can introduce zone write locking to control
request dispatching to a zoned block device and avoid write request
reordering by limiting to at most a single write request per zone
outside of the scheduler at any time.
Based on previous patches from Damien Le Moal.
Signed-off-by: Christoph Hellwig <hch@lst.de>
[Damien]
* Fixed comments and identation in blkdev.h
* Changed helper functions
* Fixed this commit message Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Bart Van Assche [Tue, 2 Jan 2018 19:39:48 +0000 (11:39 -0800)]
pktcdvd: Fix a recently introduced NULL pointer dereference
Call bdev_get_queue(bdev) after bdev->bd_disk has been initialized
instead of just before that pointer has been initialized. This patch
avoids that the following command
pktsetup 1 /dev/sr0
triggers the following kernel crash:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000548
IP: pkt_setup_dev+0x2db/0x670 [pktcdvd]
CPU: 2 PID: 724 Comm: pktsetup Not tainted 4.15.0-rc4-dbg+ #1
Call Trace:
pkt_ctl_ioctl+0xce/0x1c0 [pktcdvd]
do_vfs_ioctl+0x8e/0x670
SyS_ioctl+0x3c/0x70
entry_SYSCALL_64_fastpath+0x23/0x9a
Reported-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name> Fixes: commit ca18d6f769d2 ("block: Make most scsi_req_init() calls implicit") Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Tested-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name> Cc: Maciej S. Szmigiero <mail@maciej.szmigiero.name> Cc: <stable@vger.kernel.org> # v4.13 Signed-off-by: Jens Axboe <axboe@kernel.dk>
Bart Van Assche [Tue, 2 Jan 2018 19:39:47 +0000 (11:39 -0800)]
pktcdvd: Fix pkt_setup_dev() error path
Commit 523e1d399ce0 ("block: make gendisk hold a reference to its queue")
modified add_disk() and disk_release() but did not update any of the
error paths that trigger a put_disk() call after disk->queue has been
assigned. That introduced the following behavior in the pktcdvd driver
if pkt_new_dev() fails:
Since disk_release() calls blk_put_queue() anyway if disk->queue != NULL,
fix this by removing the blk_cleanup_queue() call from the pkt_setup_dev()
error path.
Fixes: commit 523e1d399ce0 ("block: make gendisk hold a reference to its queue") Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Tejun Heo <tj@kernel.org> Cc: Maciej S. Szmigiero <mail@maciej.szmigiero.name> Cc: <stable@vger.kernel.org> # v3.2 Signed-off-by: Jens Axboe <axboe@kernel.dk>
Javier González [Fri, 5 Jan 2018 13:16:20 +0000 (14:16 +0100)]
lightnvm: pblk: add iostat support
Since pblk registers its own block device, the iostat accounting is
not automatically done for us. Therefore, add the necessary
accounting logic to satisfy the iostat interface.
Javier González [Fri, 5 Jan 2018 13:16:17 +0000 (14:16 +0100)]
lightnvm: pblk: ensure kthread alloc. before kicking it
When creating the write thread, ensure that the kthread has been created
before initializing the timer responsible from kicking it. Otherwise, if
the kthread creation fails or gets killed from used space, we risk
kicking an empty thread structure.
Also, since the kthread creation can be interrupted form user space,
adapt the error path to not report an error when this happens, since it
is intentional that the instance creation is aborted.
Signed-off-by: Javier González <javier@cnexlabs.com>
Updated source to reflect the new timer_setup API. Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Javier González [Fri, 5 Jan 2018 13:16:16 +0000 (14:16 +0100)]
lightnvm: pblk: do not log recovery read errors
On scan recovery, reads can fail. This happens because the first page
for each line is read in order to determined if the line has been used
(and thus needs to be recovered), or not. This can lead to "empty page"
read errors.
Since these errors are normal, do not log them, as they are confusing
when reviewing the logs.
Javier González [Fri, 5 Jan 2018 13:16:14 +0000 (14:16 +0100)]
lightnvm: set target over-provision on create ioctl
Allow to set the over-provision percentage on target creation. In case
that the value is not provided, fall back to the default value set by
the target.
In pblk, set the default OP to 11% of the total size of the device
Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Javier González [Fri, 5 Jan 2018 13:16:13 +0000 (14:16 +0100)]
lightnvm: pblk: use exact free block counter in RL
Until now, pblk's rate-limiter has used a heuristic to reserve space for
GC I/O given that the over-provision area was fixed.
In preparation for allowing to define the over-provision area on target
creation, define a dedicated free_block counter in the rate-limiter to
track the number of blocks being used for user data.
Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Hans Holmberg [Fri, 5 Jan 2018 13:16:12 +0000 (14:16 +0100)]
lightnvm: pblk: remove pblk_gc_stop
pblk_gc_stop just sets pblk->gc->gc_active to zero, ignoring
the flush parameter. This is plain confusing, so remove the
function and set the gc active flag at the call points instead.
Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Hans Holmberg [Fri, 5 Jan 2018 13:16:10 +0000 (14:16 +0100)]
lightnvm: pblk: clear flush point on completed writes
Move completion of syncs and clearing of flush points to the
write completion path - this ensures that the data has been
comitted to the media before completing bios containing syncs.
Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Hans Holmberg [Fri, 5 Jan 2018 13:16:08 +0000 (14:16 +0100)]
lightnvm: pblk: refactor emeta consistency check
Currently pblk_recov_get_lba list does two separate things:
it checks the consistency of the emeta and extracts the lba list.
This patch separates the consistency check to make the code easier
to read and to prepare for version checks of the line emeta
persistent data format version.
Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Javier González [Fri, 5 Jan 2018 13:16:06 +0000 (14:16 +0100)]
lightnvm: pblk: compress and reorder helper functions
Through time, we have generated some redundant helper functions.
Refactor them to eliminate redundant and unnecessary code. Also, reorder
them to improve readability
Javier González [Fri, 5 Jan 2018 13:16:05 +0000 (14:16 +0100)]
lightnvm: guarantee target unique name across devs.
Until now, target unique naming is only guaranteed per device. This is
ok from a lightnvm perspective, but not from a sysfs one, since groups
will collide regardless of the underlying device.
Check that names are unique across all lightnvm-capable devices.
Matias Bjørling [Fri, 5 Jan 2018 13:16:02 +0000 (14:16 +0100)]
lightnvm: remove lower page tables
The lower page table is unused. All page tables reported by 1.2
devices are all reporting a sequential 1:1 page mapping. This is
also not used going forward with the 2.0 revision.
Javier González [Fri, 5 Jan 2018 13:16:01 +0000 (14:16 +0100)]
lightnvm: remove unnecessary field from nvm_rq
Remove the wait filed in nvm_rq. It is not used anymore, as targets rely
on the functionality provided by the LightNVM subsystem when sending
sync I/O.
Matias Bjørling [Fri, 5 Jan 2018 13:15:57 +0000 (14:15 +0100)]
null_blk: remove lightnvm support
With rrpc to be removed, the null_blk lightnvm support is no longer
functional. Remove the lightnvm implementation and maybe add it to
another module in the future if someone takes on the challenge.
Liu Bo [Fri, 5 Jan 2018 07:09:06 +0000 (00:09 -0700)]
blk-mq: remove confusing comment of blk_mq_sched_dispatch_requests
Commit de1482974080
("blk-mq: introduce .get_budget and .put_budget in blk_mq_ops")
changes the function to return bool type, and then commit 1f460b63d4b3
("blk-mq: don't restart queue when .get_budget returns BLK_STS_RESOURCE")
changes it back to void, but the comment remains.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Jens Axboe [Tue, 14 Nov 2017 17:24:58 +0000 (10:24 -0700)]
blk-mq: improve heavily contended tag case
Even with a number of waitqueues, we can get into a situation where we
are heavily contended on the waitqueue lock. I got a report on spc1
where we're spending seconds doing this. Arguably the use case is nasty,
I reproduce it with one device and 1000 threads banging on the device.
But that doesn't mean we shouldn't be handling it better.
What ends up happening is that a thread will fail to get a tag, add
itself to the waitqueue, and subsequently get woken up when a tag is
freed - only to find itself going back to sleep on the waitqueue.
Instead of waking all threads, use an exclusive wait and wake up our
sbitmap batch count instead. This seems to work well for me (massive
improvement for this use case), and it survives basic testing. But I
haven't fully verified it yet.
An additional improvement is running the queue and checking for a new
tag BEFORE needing to add ourselves to the waitqueue.
SELinux runs with secureexec for all non-"noatsecure" domain transitions,
which means lots of processes end up hitting the stack hard-limit change
that was introduced in order to fix a race with prlimit(). That race fix
will need to be redesigned.
Reported-by: Laura Abbott <labbott@redhat.com> Reported-by: Tomáš Trnka <trnka@scm.com> Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds [Sun, 17 Dec 2017 21:57:08 +0000 (13:57 -0800)]
Merge branch 'WIP.x86-pti.base-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull Page Table Isolation (PTI) v4.14 backporting base tree from Ingo Molnar:
"This tree contains the v4.14 PTI backport preparatory tree, which
consists of four merges of upstream trees and 7 cherry-picked commits,
which the upcoming PTI work depends on"
NOTE! The resulting tree is exactly the same as the original base tree
(ie the diff between this commit and its immediate first parent is
empty).
The only reason for this merge is literally to have a common point for
the actual PTI changes so that the commits can be shared in both the
4.15 and 4.14 trees.
* 'WIP.x86-pti.base-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/kasan: Don't use vmemmap_populate() to initialize shadow
locking/barriers: Convert users of lockless_dereference() to READ_ONCE()
locking/barriers: Add implicit smp_read_barrier_depends() to READ_ONCE()
bpf: fix build issues on um due to mising bpf_perf_event.h
perf/x86: Enable free running PEBS for REGS_USER/INTR
x86: Make X86_BUG_FXSAVE_LEAK detectable in CPUID on AMD
x86/cpufeature: Add User-Mode Instruction Prevention definitions
Linus Torvalds [Sun, 17 Dec 2017 21:54:31 +0000 (13:54 -0800)]
Merge branch 'WIP.x86-pti.base.prep-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull Page Table Isolation (PTI) preparatory tree from Ingo Molnar:
"This does a rename to free up linux/pti.h to be used by the upcoming
page table isolation feature"
* 'WIP.x86-pti.base.prep-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
drivers/misc/intel/pti: Rename the header file to free up the namespace
Arnd Bergmann [Fri, 10 Nov 2017 14:57:21 +0000 (15:57 +0100)]
cramfs: fix MTD dependency
With CONFIG_MTD=m and CONFIG_CRAMFS=y, we now get a link failure:
fs/cramfs/inode.o: In function `cramfs_mount': inode.c:(.text+0x220): undefined reference to `mount_mtd'
fs/cramfs/inode.o: In function `cramfs_mtd_fill_super':
inode.c:(.text+0x6d8): undefined reference to `mtd_point'
inode.c:(.text+0xae4): undefined reference to `mtd_unpoint'
This adds a more specific Kconfig dependency to avoid the broken
configuration.
Alternatively we could make CRAMFS itself depend on "MTD || !MTD" with a
similar result.
Fixes: 99c18ce580c6 ("cramfs: direct memory access support") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds [Sun, 17 Dec 2017 20:18:35 +0000 (12:18 -0800)]
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fixes from Al Viro:
"The alloc_super() one is a regression in this merge window, lazytime
thing is older..."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
VFS: Handle lazytime in do_mount()
alloc_super(): do ->s_umount initialization earlier
Linus Torvalds [Sun, 17 Dec 2017 20:14:33 +0000 (12:14 -0800)]
Merge tag 'ext4_for_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 fixes from Ted Ts'o:
"Fix a regression which caused us to fail to interpret symlinks in very
ancient ext3 file system images.
Also fix two xfstests failures, one of which could cause an OOPS, plus
an additional bug fix caught by fuzz testing"
* tag 'ext4_for_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: fix crash when a directory's i_size is too small
ext4: add missing error check in __ext4_new_inode()
ext4: fix fdatasync(2) after fallocate(2) operation
ext4: support fast symlinks from ext3 file systems
Andrey Ryabinin [Thu, 16 Nov 2017 01:36:35 +0000 (17:36 -0800)]
x86/mm/kasan: Don't use vmemmap_populate() to initialize shadow
[ Note, this is a Git cherry-pick of the following commit:
d17a1d97dc20: ("x86/mm/kasan: don't use vmemmap_populate() to initialize shadow")
... for easier x86 PTI code testing and back-porting. ]
The KASAN shadow is currently mapped using vmemmap_populate() since that
provides a semi-convenient way to map pages into init_top_pgt. However,
since that no longer zeroes the mapped pages, it is not suitable for
KASAN, which requires zeroed shadow memory.
Add kasan_populate_shadow() interface and use it instead of
vmemmap_populate(). Besides, this allows us to take advantage of
gigantic pages and use them to populate the shadow, which should save us
some memory wasted on page tables and reduce TLB pressure.
Link: http://lkml.kernel.org/r/20171103185147.2688-2-pasha.tatashin@oracle.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Bob Picco <bob.picco@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Alexander Potapenko <glider@google.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
Will Deacon [Tue, 24 Oct 2017 10:22:47 +0000 (11:22 +0100)]
locking/barriers: Add implicit smp_read_barrier_depends() to READ_ONCE()
[ Note, this is a Git cherry-pick of the following commit:
76ebbe78f739 ("locking/barriers: Add implicit smp_read_barrier_depends() to READ_ONCE()")
... for easier x86 PTI code testing and back-porting. ]
In preparation for the removal of lockless_dereference(), which is the
same as READ_ONCE() on all architectures other than Alpha, add an
implicit smp_read_barrier_depends() to READ_ONCE() so that it can be
used to head dependency chains on all architectures.
Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-3-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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