The ps3vram driver is a plain block device driver since commit
f507cd22035fdadd5dbb476dd05e9e7ee21c3b84 ("ps3/block: Replace mtd/ps3vram
by block/ps3vram").
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Geoff Levand <geoff@infradead.org>
Acked-by: Jim Paris <jim@jtan.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The pmem driver maps NVDIMM uncacheable so that we don't lose
data which hasn't reached non-volatile storage in the case of a
crash. Change this to Write-Through mode which provides uncached
writes but cached reads, thus improving read performance.
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Elliott@hp.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: jgross@suse.com
Cc: konrad.wilk@oracle.com
Cc: linux-mm <linux-mm@kvack.org>
Cc: linux-nvdimm@lists.01.org
Cc: stefan.bader@canonical.com
Cc: yigal@plexistor.com
Link: http://lkml.kernel.org/r/1433436928-31903-14-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Extend xen/block to support multi-page ring, so that more requests can be
issued by using more than one pages as the request ring between blkfront
and backend.
As a result, the performance can get improved significantly.
We got some impressive improvements on our highend iscsi storage cluster
backend. If using 64 pages as the ring, the IOPS increased about 15 times
for the throughput testing and above doubled for the latency testing.
The reason was the limit on outstanding requests is 32 if use only one-page
ring, but in our case the iscsi lun was spread across about 100 physical
drives, 32 was really not enough to keep them busy.
Changes in v2:
- Rebased to 4.0-rc6.
- Document on how multi-page ring feature working to linux io/blkif.h.
Changes in v3:
- Remove changes to linux io/blkif.h and follow the protocol defined
in io/blkif.h of XEN tree.
- Rebased to 4.1-rc3
Changes in v4:
- Turn to use 'ring-page-order' and 'max-ring-page-order'.
- A few comments from Roger.
Changes in v5:
- Clarify with 4k granularity to comment
- Address more comments from Roger
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The major responsibility of talk_to_blkback() is allocate and initialize
the request ring and write the ring info to xenstore.
But this work should be done after backend entered 'XenbusStateInitWait' as
defined in the protocol file.
See xen/include/public/io/blkif.h in XEN git tree:
Front Back
================================= =====================================
XenbusStateInitialising XenbusStateInitialising
o Query virtual device o Query backend device identification
properties. data.
o Setup OS device instance. o Open and validate backend device.
o Publish backend features and
transport parameters.
|
|
V
XenbusStateInitWait
o Query backend features and
transport parameters.
o Allocate and initialize the
request ring.
There is no problem with this yet, but it is an violation of the design and
furthermore it would not allow frontend/backend to negotiate 'multi-page'
and 'multi-queue' features.
Changes in v2:
- Re-write the commit message to be more clear.
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This is a pre-patch for multi-page ring feature.
In connect_ring, we can know exactly how many pages are used for the shared
ring, delay pending_req allocation here so that we won't waste too much memory.
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Namespaces may be dynamically allocated and deleted or attached and
detached. This has the driver rescan the device for namespace changes
after each device reset or namespace change asynchronous event.
There could potentially be many detached namespaces that we don't want
polluting /dev/ with unusable block handles, so this will delete disks
if the namespace is not active as indicated by the response from identify
namespace. This also skips adding the disk if no capacity is provisioned
to the namespace in the first place.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Protects against reordering and/or preempting which would allow the
kthread to access the queue descriptor before it is set up
Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
Acked-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We need the ability to perform an nvme controller reset as discussed on
the mailing list thread:
http://lists.infradead.org/pipermail/linux-nvme/2015-March/001585.html
This adds a sysfs entry that when written to will reset perform an NVMe
controller reset if the controller was successfully initialized in the
first place.
This also adds locking around resetting the device in the async probe
method so the driver can't schedule two resets.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Cc: Brandon Schultz <brandon.schulz@hgst.com>
Cc: David Sariel <david.sariel@pmcs.com>
Updated by Jens to:
1) Merge this with the ioctl reset patch from David Sariel. The ioctl
path now shares the reset code from the sysfs path.
2) Don't flush work if we fail issuing the reset.
Signed-off-by: Jens Axboe <axboe@fb.com>
With the planned cgroup writeback support, backing-dev related
declarations will be more widely used across block and cgroup;
unfortunately, including backing-dev.h from include/linux/blkdev.h
makes cyclic include dependency quite likely.
This patch separates out backing-dev-defs.h which only has the
essential definitions and updates blkdev.h to include it. c files
which need access to more backing-dev details now include
backing-dev.h directly. This takes backing-dev.h off the common
include dependency chain making it a lot easier to use it across block
and cgroup.
v2: fs/fat build failure fixed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <axboe@fb.com>
Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback)
and the role of the separation is unclear. For cgroup support for
writeback IOs, a bdi will be updated to host multiple wb's where each
wb serves writeback IOs of a different cgroup on the bdi. To achieve
that, a wb should carry all states necessary for servicing writeback
IOs for a cgroup independently.
This patch moves bdi->state into wb.
* enum bdi_state is renamed to wb_state and the prefix of all enums is
changed from BDI_ to WB_.
* Explicit zeroing of bdi->state is removed without adding zeoring of
wb->state as the whole data structure is zeroed on init anyway.
* As there's still only one bdi_writeback per backing_dev_info, all
uses of bdi->state are mechanically replaced with bdi->wb.state
introducing no behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: drbd-dev@lists.linbit.com
Cc: Neil Brown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
When irqmode=2 (IRQ completion handler is timer) and queue_mode=1
(Block interface to use is rq), the completion handler should restart
request handling for any pending requests on a queue because request
processing stops when the number of commands are queued more than
hw_queue_depth (null_rq_prep_fn returns BLKPREP_DEFER).
Without this change, the following command cannot finish.
# modprobe null_blk irqmode=2 queue_mode=1 hw_queue_depth=1
# fio --name=t --rw=read --size=1g --direct=1 \
--ioengine=libaio --iodepth=64 --filename=/dev/nullb0
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
When irqmode=2 (IRQ completion handler is timer), timer handler should
be called on the same CPU where the timer has been started.
Since completion_queues are per-cpu and the completion handler only
touches completion_queue for local CPU, we need to prevent the handler
from running on a different CPU where the timer has been started.
Otherwise, the IO cannot be completed until another completion handler
is executed on that CPU.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The driver needs to track shared tags to support multiple namespaces
that may be dynamically allocated or deleted. Relying on the first
request_queue's hctx's is not appropriate as we cannot clear outstanding
tags for all namespaces using this handle, nor can the driver easily track
all request_queue's hctx as namespaces are attached/detached. Instead,
this patch uses the nvme_dev's tagset to get the shared tag resources
instead of through a request_queue hctx.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
'0' is now used as the default cmd_per_lun value,
so there's no need to explicitly set it to '1' in the
host template.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
Modify paride driver to use the new parallel port device model.
Tested-by: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The hpsa driver carries a more recent version,
copy the table from there.
Signed-off-by: Tomas Henzl <thenzl@redhat.com>
Acked-by: Don Brace <Don.Brace@pmcs.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
and devices not supported by this driver from unresettable list
Signed-off-by: Tomas Henzl <thenzl@redhat.com>
Acked-by: Don Brace <Don.Brace@pmcs.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
Do not retry failed sync commands so the original status may be seen
without issuing unnecessary retries.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
A recent change to the ioctl handling caused a new harmless
warning in the NVMe driver on all 32-bit machines:
drivers/block/nvme-core.c: In function 'nvme_submit_io':
drivers/block/nvme-core.c:1794:29: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
In order to shup up that warning, this introduces a new
temporary variable that uses a double cast to extract
the pointer from an __u64 structure member.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: a67a95134ff ("NVMe: Meta data handling through submit io ioctl")
Acked-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Most code already uses consts for the struct kernel_param_ops,
sweep the kernel for the last offending stragglers. Other than
include/linux/moduleparam.h and kernel/params.c all other changes
were generated with the following Coccinelle SmPL patch. Merge
conflicts between trees can be handled with Coccinelle.
In the future git could get Coccinelle merge support to deal with
patch --> fail --> grammar --> Coccinelle --> new patch conflicts
automatically for us on patches where the grammar is available and
the patch is of high confidence. Consider this a feature request.
Test compiled on x86_64 against:
* allnoconfig
* allmodconfig
* allyesconfig
@ const_found @
identifier ops;
@@
const struct kernel_param_ops ops = {
};
@ const_not_found depends on !const_found @
identifier ops;
@@
-struct kernel_param_ops ops = {
+const struct kernel_param_ops ops = {
};
Generated-by: Coccinelle SmPL
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Junio C Hamano <gitster@pobox.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: cocci@systeme.lip6.fr
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Conflicts:
drivers/net/ethernet/cadence/macb.c
drivers/net/phy/phy.c
include/linux/skbuff.h
net/ipv4/tcp.c
net/switchdev/switchdev.c
Switchdev was a case of RTNH_H_{EXTERNAL --> OFFLOAD}
renaming overlapping with net-next changes of various
sorts.
phy.c was a case of two changes, one adding a local
variable to a function whilst the second was removing
one.
tcp.c overlapped a deadlock fix with the addition of new tcp_info
statistic values.
macb.c involved the addition of two zyncq device entries.
skbuff.h involved adding back ipv4_daddr to nf_bridge_info
whilst net-next changes put two other existing members of
that struct into a union.
Signed-off-by: David S. Miller <davem@davemloft.net>
Replaces req->sense_len usage, which is not owned by the LLD, to
req->special to contain the command result for driver created commands,
and sets the result unconditionally on completion.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@fb.com>
Fixes: d29ec8241c10 ("nvme: submit internal commands through the block layer")
Signed-off-by: Jens Axboe <axboe@fb.com>
Use block layer queues with an internal cmd_type to submit internally
generated NVMe commands. This both simplifies the code a lot and allow
for a better structure. For example now the LighNVM code can construct
commands without knowing the details of the underlying I/O descriptors.
Or a future NVMe over network target could inject commands, as well as
could the SCSI translation and ioctl code be reused for such a beast.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
NVMe device always support the FUA bit, and the SCSI translations
accepts the DPO bit, which doesn't have much of a meaning for us.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Erorr handling for the scsi translation was completely broken, as there
were two different positive error number spaces overlapping. Fix this
up by removing one of them, and centralizing the generation of the other
positive values in a single place. Also fix up a few places that didn't
handle the NVMe error codes properly.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This function handles two totally different opcodes, so split it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Most users want the generic device, so store that in struct nvme_dev
instead of the pci_dev. This also happens to be a nice step towards
making some code reusable for non-PCI transports.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Note that we keep the unused timeout argument, but allow callers to
pass 0 instead of a timeout if they want the default. This will allow
adding a timeout to the pass through path later on.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
gcc, righfully, complains:
drivers/block/loop.c:1369:1: warning: label 'out' defined but not used [-Wunused-label]
Kill it.
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jarod Wilson <jarod@redhat.com>
Acked-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
loop_clr_fd() can be run piggyback with lo_release(), and
under this situation, reread partition may always fail because
bd_mutex has been held already.
This patch detects the situation by the reference count, and
call __blkdev_reread_part() to avoid acquiring the lock again.
In the meantime, this patch switches to new kernel APIs
of blkdev_reread_part() and __blkdev_reread_part().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jarod Wilson <jarod@redhat.com>
Acked-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The lo_ctl_mutex is held for running all ioctl handlers, and
in some ioctl handlers, ioctl_by_bdev(BLKRRPART) is called for
rereading partitions, which requires bd_mutex.
So it is easy to cause failure because trylock(bd_mutex) may
fail inside blkdev_reread_part(), and follows the lock context:
blkid or other application:
->open()
->mutex_lock(bd_mutex)
->lo_open()
->mutex_lock(lo_ctl_mutex)
losetup(set fd ioctl):
->mutex_lock(lo_ctl_mutex)
->ioctl_by_bdev(BLKRRPART)
->trylock(bd_mutex)
This patch trys to eliminate the ABBA lock dependency by removing
lo_ctl_mutext in lo_open() with the following approach:
1) make lo_refcnt as atomic_t and avoid acquiring lo_ctl_mutex in lo_open():
- for open vs. add/del loop, no any problem because of loop_index_mutex
- freeze request queue during clr_fd, so I/O can't come until
clearing fd is completed, like the effect of holding lo_ctl_mutex
in lo_open
- both open() and release() have been serialized by bd_mutex already
2) don't hold lo_ctl_mutex for decreasing/checking lo_refcnt in
lo_release(), then lo_ctl_mutex is only required for the last release.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jarod Wilson <jarod@redhat.com>
Acked-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The queue_lock needs to be taken with irqs disabled. This is mostly
due to the old pre blk-mq usage pattern, but we've also picked it up
in most of the few places where we use the queue_lock with blk-mq.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
The hpsa driver carries a more recent version,
copy the table from there.
Signed-off-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
and devices not supported by this driver from unresettable list
Signed-off-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Four minor merge conflicts:
1) qca_spi.c renamed the local variable used for the SPI device
from spi_device to spi, meanwhile the spi_set_drvdata() call
got moved further up in the probe function.
2) Two changes were both adding new members to codel params
structure, and thus we had overlapping changes to the
initializer function.
3) 'net' was making a fix to sk_release_kernel() which is
completely removed in 'net-next'.
4) In net_namespace.c, the rtnl_net_fill() call for GET operations
had the command value fixed, meanwhile 'net-next' adjusted the
argument signature a bit.
This also matches example merge resolutions posted by Stephen
Rothwell over the past two days.
Signed-off-by: David S. Miller <davem@davemloft.net>
If userspace asks for an INQUIRY buffer smaller than 36 bytes, the SCSI
translation layer will happily write past the end of the INQUIRY buffer
allocation.
This is fairly easily reproducible by running the libiscsi test
suite and then starting an xfstests run.
Fixes: 4f1982 ("NVMe: Update SCSI Inquiry VPD 83h translation")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This is long overdue, and is part of cleaning up how we allocate kernel
sockets that don't reference count struct net.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull block fixes from Jens Axboe:
"A collection of fixes since the merge window;
- fix for a double elevator module release, from Chao Yu. Ancient bug.
- the splice() MORE flag fix from Christophe Leroy.
- a fix for NVMe, fixing a patch that went in in the merge window.
From Keith.
- two fixes for blk-mq CPU hotplug handling, from Ming Lei.
- bdi vs blockdev lifetime fix from Neil Brown, fixing and oops in md.
- two blk-mq fixes from Shaohua, fixing a race on queue stop and a
bad merge issue with FUA writes.
- division-by-zero fix for writeback from Tejun.
- a block bounce page accounting fix, making sure we inc/dec after
bouncing so that pre/post IO pages match up. From Wang YanQing"
* 'for-linus' of git://git.kernel.dk/linux-block:
splice: sendfile() at once fails for big files
blk-mq: don't lose requests if a stopped queue restarts
blk-mq: fix FUA request hang
block: destroy bdi before blockdev is unregistered.
block:bounce: fix call inc_|dec_zone_page_state on different pages confuse value of NR_BOUNCE
elevator: fix double release of elevator module
writeback: use |1 instead of +1 to protect against div by zero
blk-mq: fix CPU hotplug handling
blk-mq: fix race between timeout and CPU hotplug
NVMe: Fix VPD B0 max sectors translation
- Fix blkback regression if using persistent grants.
- Fix various event channel related suspend/resume bugs.
- Fix AMD x86 regression with X86_BUG_SYSRET_SS_ATTRS.
- SWIOTLB on ARM now uses frames <4 GiB (if available) so device only
capable of 32-bit DMA work.
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Merge tag 'for-linus-4.1b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen bug fixes from David Vrabel:
- fix blkback regression if using persistent grants
- fix various event channel related suspend/resume bugs
- fix AMD x86 regression with X86_BUG_SYSRET_SS_ATTRS
- SWIOTLB on ARM now uses frames <4 GiB (if available) so device only
capable of 32-bit DMA work.
* tag 'for-linus-4.1b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen: Add __GFP_DMA flag when xen_swiotlb_init gets free pages on ARM
hypervisor/x86/xen: Unset X86_BUG_SYSRET_SS_ATTRS on Xen PV guests
xen/events: Set irq_info->evtchn before binding the channel to CPU in __startup_pirq()
xen/console: Update console event channel on resume
xen/xenbus: Update xenbus event channel on resume
xen/events: Clear cpu_evtchn_mask before resuming
xen-pciback: Add name prefix to global 'permissive' variable
xen: Suspend ticks on all CPUs during suspend
xen/grant: introduce func gnttab_unmap_refs_sync()
xen/blkback: safely unmap purge persistent grants
Revert commit c72c6160d967ed26a0b136dbab337f821d233509
It was intended to be a cosmetic change that w/o any functional change
and was part of a bigger change:
http://lkml.iu.edu/hypermail/linux/kernel/1503.1/01818.html
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If there are too many pending per work I/O, too many
high priority work thread can be generated so that
system performance can be effected.
This patch limits the max_active parameter of workqueue as 16.
This patch fixes Fedora 22 live booting performance
regression when it is booted from squashfs over dm
based on loop, and looks the following reasons are
related with the problem:
- not like other filesyststems(such as ext4), squashfs
is a bit special, and I observed that increasing I/O jobs
to access file in squashfs only improve I/O performance a
little, but it can make big difference for ext4
- nested loop: both squashfs.img and ext3fs.img are mounted
as loop block, and ext3fs.img is inside the squashfs
- during booting, lots of tasks may run concurrently
Fixes: b5dd2f6047ca108001328aac0e8588edd15f1778
Cc: stable@vger.kernel.org (v4.0)
Cc: Justin M. Forbes <jforbes@fedoraproject.org>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
Documentation/workqueue.txt:
If there is dependency among multiple work items used
during memory reclaim, they should be queued to separate
wq each with WQ_MEM_RECLAIM.
Loop devices can be stacked, so we have to convert to per-device
workqueue. One example is Fedora live CD.
Fixes: b5dd2f6047ca108001328aac0e8588edd15f1778
Cc: stable@vger.kernel.org (v4.0)
Cc: Justin M. Forbes <jforbes@fedoraproject.org>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
