We have split the setting up of all the resources in two steps:
1) talk_to_blkback - which figures out the num_ring_pages (from
the default value of zero), sets up shadow and so
2) blkfront_connect - does the real part of filling out the
internal structures.
The problem is if we bypass the 1) step and go straight to 2)
and call blkfront_setup_indirect where we use the macro
BLK_RING_SIZE - which returns an negative value (because
sz is zero - since num_ring_pages is zero - since it has never
been set).
We can fix this by making sure that we always have called
talk_to_blkback before going to blkfront_connect.
Or we could set in blkfront_probe info->nr_ring_pages = 1
to have a default value. But that looks odd - as we haven't
actually negotiated any ring size.
This patch changes XenbusStateConnected state to detect if
we haven't done the initial handshake - and if so continue
on as if were in XenbusStateInitWait state.
We also roll the error recovery (freeing the structure) into
talk_to_blkback error path - which is safe since that function
is only called from blkback_changed.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The minimal size of request in the block framework is always PAGE_SIZE.
It means that when 64KB guest is support, the request will at least be
64KB.
Although, if the backend doesn't support indirect descriptor (such as QDISK
in QEMU), a ring request is only able to accommodate 11 segments of 4KB
(i.e 44KB).
The current frontend is assuming that an I/O request will always fit in
a ring request. This is not true any more when using 64KB page
granularity and will therefore crash during boot.
On ARM64, the ABI is completely neutral to the page granularity used by
the domU. The guest has the choice between different page granularity
supported by the processors (for instance on ARM64: 4KB, 16KB, 64KB).
This can't be enforced by the hypervisor and therefore it's possible to
run guests using different page granularity.
So we can't mandate the block backend to support indirect descriptor
when the frontend is using 64KB page granularity and have to fix it
properly in the frontend.
The solution exposed below is based on modifying directly the frontend
guest rather than asking the block framework to support smaller size
(i.e < PAGE_SIZE). This is because the change is the block framework are
not trivial as everything seems to relying on a struct *page (see [1]).
Although, it may be possible that someone succeed to do it in the future
and we would therefore be able to use it.
Given that a block request may not fit in a single ring request, a
second request is introduced for the data that cannot fit in the first
one. This means that the second ring request should never be used on
Linux if the page size is smaller than 44KB.
To achieve the support of the extra ring request, the block queue size
is divided by two. Therefore, the ring will always contain enough space
to accommodate 2 ring requests. While this will reduce the overall
performance, it will make the implementation more contained. The way
forward to get better performance is to implement in the backend either
indirect descriptor or multiple grants ring.
Note that the parameters blk_queue_max_* helpers haven't been updated.
The block code will set the mimimum size supported and we may be able
to support directly any change in the block framework that lower down
the minimal size of a request.
[1] http://lists.xen.org/archives/html/xen-devel/2015-08/msg02200.html
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The code to get a request is always the same. Therefore we can factorize
it in a single function.
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
According to this piece code:
"
pr_info("Invalid max_ring_order (%d), will use default max: %d.\n",
xen_blkif_max_ring_order, XENBUS_MAX_RING_GRANT_ORDER);
"
if xen_blkif_max_ring_order is bigger that XENBUS_MAX_RING_GRANT_ORDER,
need to set xen_blkif_max_ring_order using XENBUS_MAX_RING_GRANT_ORDER,
but not 0.
Signed-off-by: Peng Fan <van.freenix@gmail.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Make persistent grants per-queue/ring instead of per-device, so that we can
drop the 'dev_lock' and get better scalability.
Test was done based on null_blk driver:
dom0: v4.2-rc8 16vcpus 10GB "modprobe null_blk"
domu: v4.2-rc8 16vcpus 10GB
[test]
rw=read
direct=1
ioengine=libaio
bs=4k
time_based
runtime=30
filename=/dev/xvdb
numjobs=16
iodepth=64
iodepth_batch=64
iodepth_batch_complete=64
group_reporting
Queues: 1 4 8 16
Iops orig(k): 810 1064 780 700
Iops patched(k): 810 1230(~20%) 1024(~20%) 850(~20%)
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
We do the same exact operations a bit earlier in the
function.
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The max number of hardware queues for xen/blkfront is set by parameter
'max_queues'(default 4), while it is also capped by the max value that the
xen/blkback exposes through XenStore key 'multi-queue-max-queues'.
The negotiated number is the smaller one and would be written back to xenstore
as "multi-queue-num-queues", blkback needs to read this negotiated number.
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
After patch "xen/blkfront: separate per ring information out of device
info", per-ring data is protected by a per-device lock ('io_lock').
This is not a good way and will effect the scalability, so introduce a
per-ring lock ('ring_lock').
The old 'io_lock' is renamed to 'dev_lock' which protects the ->grants list and
->persistent_gnts_c which are shared by all rings.
Note that in 'blkfront_probe' the 'blkfront_info' is setup via kzalloc
so setting ->persistent_gnts_c to zero is not needed.
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Preparatory patch for multiple hardware queues (rings). The number of
rings is unconditionally set to 1, larger number will be enabled in
patch "xen/blkfront: negotiate number of queues/rings to be used with backend"
so as to make review easier.
Note that blkfront_gather_backend_features does not call
blkfront_setup_indirect anymore (as that needs to be done per ring).
That means that in blkif_recover/blkif_connect we have to do it in a loop
(bounded by nr_rings).
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Split per ring information to a new structure "blkfront_ring_info".
A ring is the representation of a hardware queue, every vbd device can associate
with one or more rings depending on how many hardware queues/rings to be used.
This patch is a preparation for supporting real multi hardware queues/rings.
We also add a backpointer to 'struct blkfront_info' (dev_info) which
is not needed (we could use containers_of) but further patch
("xen/blkfront: pseudo support for multi hardware queues/rings")
will make allocation of 'blkfront_ring_info' dynamic.
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
- Improve balloon driver memory hotplug placement.
- Use unpopulated hotplugged memory for foreign pages (if
supported/enabled).
- Support 64 KiB guest pages on arm64.
- CPU hotplug support on arm/arm64.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQEcBAABAgAGBQJWOeSkAAoJEFxbo/MsZsTRph0H/0nE8Tx0GyGtOyCYfBdInTvI
WgjvL8VR1XrweZMVis3668MzhLSYg6b5lvJsoi+L3jlzYRyze43iHXsKfvp+8p0o
TVUhFnlHEHF8ASEtPydAi6HgS7Dn9OQ9LaZ45R1Gk0rHnwJjIQonhTn2jB0yS9Am
Hf4aZXP2NVZphjYcloqNsLH0G6mGLtgq8cS0uKcVO2YIrR4Dr3sfj9qfq9mflf8n
sA/5ifoHRfOUD1vJzYs4YmIBUv270jSsprWK/Mi2oXIxUTBpKRAV1RVCAPW6GFci
HIZjIJkjEPWLsvxWEs0dUFJQGp3jel5h8vFPkDWBYs3+9rILU2DnLWpKGNDHx3k=
=vUfa
-----END PGP SIGNATURE-----
Merge tag 'for-linus-4.4-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from David Vrabel:
- Improve balloon driver memory hotplug placement.
- Use unpopulated hotplugged memory for foreign pages (if
supported/enabled).
- Support 64 KiB guest pages on arm64.
- CPU hotplug support on arm/arm64.
* tag 'for-linus-4.4-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (44 commits)
xen: fix the check of e_pfn in xen_find_pfn_range
x86/xen: add reschedule point when mapping foreign GFNs
xen/arm: don't try to re-register vcpu_info on cpu_hotplug.
xen, cpu_hotplug: call device_offline instead of cpu_down
xen/arm: Enable cpu_hotplug.c
xenbus: Support multiple grants ring with 64KB
xen/grant-table: Add an helper to iterate over a specific number of grants
xen/xenbus: Rename *RING_PAGE* to *RING_GRANT*
xen/arm: correct comment in enlighten.c
xen/gntdev: use types from linux/types.h in userspace headers
xen/gntalloc: use types from linux/types.h in userspace headers
xen/balloon: Use the correct sizeof when declaring frame_list
xen/swiotlb: Add support for 64KB page granularity
xen/swiotlb: Pass addresses rather than frame numbers to xen_arch_need_swiotlb
arm/xen: Add support for 64KB page granularity
xen/privcmd: Add support for Linux 64KB page granularity
net/xen-netback: Make it running on 64KB page granularity
net/xen-netfront: Make it running on 64KB page granularity
block/xen-blkback: Make it running on 64KB page granularity
block/xen-blkfront: Make it running on 64KB page granularity
...
Linux may use a different page size than the size of grant. So make
clear that the order is actually in number of grant.
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
The PV block protocol is using 4KB page granularity. The goal of this
patch is to allow a Linux using 64KB page granularity using block
device on a non-modified Xen.
The block API is using segment which should at least be the size of a
Linux page. Therefore, the driver will have to break the page in chunk
of 4K before giving the page to the backend.
When breaking a 64KB segment in 4KB chunks, it is possible that some
chunks are empty. As the PV protocol always require to have data in the
chunk, we have to count the number of Xen page which will be in use and
avoid sending empty chunks.
Note that, a pre-defined number of grants are reserved before preparing
the request. This pre-defined number is based on the number and the
maximum size of the segments. If each segment contains a very small
amount of data, the driver may reserve too many grants (16 grants is
reserved per segment with 64KB page granularity).
Furthermore, in the case of persistent grants we allocate one Linux page
per grant although only the first 4KB of the page will be effectively
in use. This could be improved by sharing the page with multiple grants.
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Prepare the code to support 64KB page granularity. The first
implementation will use a full Linux page per indirect and persistent
grant. When non-persistent grant is used, each page of a bio request
may be split in multiple grant.
Furthermore, the field page of the grant structure is only used to copy
data from persistent grant or indirect grant. Avoid to set it for other
use case as it will have no meaning given the page will be split in
multiple grant.
Provide 2 functions, to setup indirect grant, the other for bio page.
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
All the usage of the field pfn are done using the same idiom:
pfn_to_page(grant->pfn)
This will return always the same page. Store directly the page in the
grant to clean up the code.
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Currently, blkif_queue_request has 2 distinct execution path:
- Send a discard request
- Send a read/write request
The function is also allocating grants to use for generating the
request. Although, this is only used for read/write request.
Rather than having a function with 2 distinct execution path, separate
the function in 2. This will also remove one level of tabulation.
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Konrad writes:
Please git pull an update branch to your 'for-4.3/drivers' branch (which
oddly I don't see does not have the previous pull?)
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git stable/for-jens-4.3
which has two fixes - one where we use the Xen blockfront EFI driver and
don't release all the requests, the other if the allocation of resources
for a particular state failed - we would go back 'Closing' and assume
that an structure would be allocated while in fact it may not be - and
crash.
xen-blkfront will crash if the check to talk_to_blkback()
in blkback_changed()(XenbusStateInitWait) returns an error.
The driver data is freed and info is set to NULL. Later during
the close process via talk_to_blkback's call to xenbus_dev_fatal()
the null pointer is passed to and dereference in blkfront_closing.
CC: stable@vger.kernel.org
Signed-off-by: Cathy Avery <cathy.avery@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
blk_mq_complete_request may be a no-op if the request has already
been completed by others means (e.g. a timeout or cancellation), but
currently drivers have to set rq->errors before calling
blk_mq_complete_request, which might leave us with the wrong error value.
Add an error parameter to blk_mq_complete_request so that we can
defer setting rq->errors until we known we won the race to complete the
request.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
- Use the correct GFN/BFN terms more consistently.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQEcBAABAgAGBQJV8VRMAAoJEFxbo/MsZsTRiGQH/i/jrAJUJfrFC2PINaA2gDwe
O0dlrkCiSgAYChGmxxxXZQSPM5Po5+EbT/dLjZ/uvSooeorM9RYY/mFo7ut/qLep
4pyQUuwGtebWGBZTrj9sygUVXVhgJnyoZxskNUbhj9zvP7hb9++IiI78mzne6cpj
lCh/7Z2dgpfRcKlNRu+qpzP79Uc7OqIfDK+IZLrQKlXa7IQDJTQYoRjbKpfCtmMV
BEG3kN9ESx5tLzYiAfxvaxVXl9WQFEoktqe9V8IgOQlVRLgJ2DQWS6vmraGrokWM
3HDOCHtRCXlPhu1Vnrp0R9OgqWbz8FJnmVAndXT8r3Nsjjmd0aLwhJx7YAReO/4=
=JDia
-----END PGP SIGNATURE-----
Merge tag 'for-linus-4.3-rc0b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen terminology fixes from David Vrabel:
"Use the correct GFN/BFN terms more consistently"
* tag 'for-linus-4.3-rc0b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/xenbus: Rename the variable xen_store_mfn to xen_store_gfn
xen/privcmd: Further s/MFN/GFN/ clean-up
hvc/xen: Further s/MFN/GFN clean-up
video/xen-fbfront: Further s/MFN/GFN clean-up
xen/tmem: Use xen_page_to_gfn rather than pfn_to_gfn
xen: Use correctly the Xen memory terminologies
arm/xen: implement correctly pfn_to_mfn
xen: Make clear that swiotlb and biomerge are dealing with DMA address
- Convert xen-blkfront to the multiqueue API
- [arm] Support binding event channels to different VCPUs.
- [x86] Support > 512 GiB in a PV guests (off by default as such a
guest cannot be migrated with the current toolstack).
- [x86] PMU support for PV dom0 (limited support for using perf with
Xen and other guests).
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQEcBAABAgAGBQJV7wIdAAoJEFxbo/MsZsTR0hEH/04HTKLKGnSJpZ5WbMPxqZxE
UqGlvhvVWNAmFocZmbPcEi9T1qtcFrX5pM55JQr6UmAp3ovYsT2q1Q1kKaOaawks
pSfc/YEH3oQW5VUQ9Lm9Ru5Z8Btox0WrzRREO92OF36UOgUOBOLkGsUfOwDinNIM
lSk2djbYwDYAsoeC3PHB32wwMI//Lz6B/9ZVXcyL6ULynt1ULdspETjGnptRPZa7
JTB5L4/soioKOn18HDwwOhKmvaFUPQv9Odnv7dc85XwZreajhM/KMu3qFbMDaF/d
WVB1NMeCBdQYgjOrUjrmpyr5uTMySiQEG54cplrEKinfeZgKlEyjKvjcAfJfiac=
=Ktjl
-----END PGP SIGNATURE-----
Merge tag 'for-linus-4.3-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from David Vrabel:
"Xen features and fixes for 4.3:
- Convert xen-blkfront to the multiqueue API
- [arm] Support binding event channels to different VCPUs.
- [x86] Support > 512 GiB in a PV guests (off by default as such a
guest cannot be migrated with the current toolstack).
- [x86] PMU support for PV dom0 (limited support for using perf with
Xen and other guests)"
* tag 'for-linus-4.3-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (33 commits)
xen: switch extra memory accounting to use pfns
xen: limit memory to architectural maximum
xen: avoid another early crash of memory limited dom0
xen: avoid early crash of memory limited dom0
arm/xen: Remove helpers which are PV specific
xen/x86: Don't try to set PCE bit in CR4
xen/PMU: PMU emulation code
xen/PMU: Intercept PMU-related MSR and APIC accesses
xen/PMU: Describe vendor-specific PMU registers
xen/PMU: Initialization code for Xen PMU
xen/PMU: Sysfs interface for setting Xen PMU mode
xen: xensyms support
xen: remove no longer needed p2m.h
xen: allow more than 512 GB of RAM for 64 bit pv-domains
xen: move p2m list if conflicting with e820 map
xen: add explicit memblock_reserve() calls for special pages
mm: provide early_memremap_ro to establish read-only mapping
xen: check for initrd conflicting with e820 map
xen: check pre-allocated page tables for conflict with memory map
xen: check for kernel memory conflicting with memory layout
...
Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN
is meant, I suspect this is because the first support for Xen was for
PV. This resulted in some misimplementation of helpers on ARM and
confused developers about the expected behavior.
For instance, with pfn_to_mfn, we expect to get an MFN based on the name.
Although, if we look at the implementation on x86, it's returning a GFN.
For clarity and avoid new confusion, replace any reference to mfn with
gfn in any helpers used by PV drivers. The x86 code will still keep some
reference of pfn_to_mfn which may be used by all kind of guests
No changes as been made in the hypercall field, even
though they may be invalid, in order to keep the same as the defintion
in xen repo.
Note that page_to_mfn has been renamed to xen_page_to_gfn to avoid a
name to close to the KVM function gfn_to_page.
Take also the opportunity to simplify simple construction such
as pfn_to_mfn(page_to_pfn(page)) into xen_page_to_gfn. More complex clean up
will come in follow-up patches.
[1] http://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=e758ed14f390342513405dd766e874934573e6cb
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Pull core block updates from Jens Axboe:
"This first core part of the block IO changes contains:
- Cleanup of the bio IO error signaling from Christoph. We used to
rely on the uptodate bit and passing around of an error, now we
store the error in the bio itself.
- Improvement of the above from myself, by shrinking the bio size
down again to fit in two cachelines on x86-64.
- Revert of the max_hw_sectors cap removal from a revision again,
from Jeff Moyer. This caused performance regressions in various
tests. Reinstate the limit, bump it to a more reasonable size
instead.
- Make /sys/block/<dev>/queue/discard_max_bytes writeable, by me.
Most devices have huge trim limits, which can cause nasty latencies
when deleting files. Enable the admin to configure the size down.
We will look into having a more sane default instead of UINT_MAX
sectors.
- Improvement of the SGP gaps logic from Keith Busch.
- Enable the block core to handle arbitrarily sized bios, which
enables a nice simplification of bio_add_page() (which is an IO hot
path). From Kent.
- Improvements to the partition io stats accounting, making it
faster. From Ming Lei.
- Also from Ming Lei, a basic fixup for overflow of the sysfs pending
file in blk-mq, as well as a fix for a blk-mq timeout race
condition.
- Ming Lin has been carrying Kents above mentioned patches forward
for a while, and testing them. Ming also did a few fixes around
that.
- Sasha Levin found and fixed a use-after-free problem introduced by
the bio->bi_error changes from Christoph.
- Small blk cgroup cleanup from Viresh Kumar"
* 'for-4.3/core' of git://git.kernel.dk/linux-block: (26 commits)
blk: Fix bio_io_vec index when checking bvec gaps
block: Replace SG_GAPS with new queue limits mask
block: bump BLK_DEF_MAX_SECTORS to 2560
Revert "block: remove artifical max_hw_sectors cap"
blk-mq: fix race between timeout and freeing request
blk-mq: fix buffer overflow when reading sysfs file of 'pending'
Documentation: update notes in biovecs about arbitrarily sized bios
block: remove bio_get_nr_vecs()
fs: use helper bio_add_page() instead of open coding on bi_io_vec
block: kill merge_bvec_fn() completely
md/raid5: get rid of bio_fits_rdev()
md/raid5: split bio for chunk_aligned_read
block: remove split code in blkdev_issue_{discard,write_same}
btrfs: remove bio splitting and merge_bvec_fn() calls
bcache: remove driver private bio splitting code
block: simplify bio_add_page()
block: make generic_make_request handle arbitrarily sized bios
blk-cgroup: Drop unlikely before IS_ERR(_OR_NULL)
block: don't access bio->bi_error after bio_put()
block: shrink struct bio down to 2 cache lines again
...
Note: This patch is based on original work of Arianna's internship for
GNOME's Outreach Program for Women.
Only one hardware queue is used now, so there is no significant
performance change
The legacy non-mq code is deleted completely which is the same as other
drivers like virtio, mtip, and nvme.
Also dropped one unnecessary holding of info->io_lock when calling
blk_mq_stop_hw_queues().
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jens Axboe <axboe@fb.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Currently we have two different ways to signal an I/O error on a BIO:
(1) by clearing the BIO_UPTODATE flag
(2) by returning a Linux errno value to the bi_end_io callback
The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario. Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.
So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Konrad writes:
"There are three bugs that have been found in the xen-blkfront (and
backend). Two of them have the stable tree CC-ed. They have been found
where an guest is migrating to a host that is missing
'feature-persistent' support (from one that has it enabled). We end up
hitting an BUG() in the driver code."
We should consider info->feature_persistent when adding indirect page to list
info->indirect_pages, else the BUG_ON() in blkif_free() would be triggered.
When we are using persistent grants the indirect_pages list
should always be empty because blkfront has pre-allocated enough
persistent pages to fill all requests on the ring.
CC: stable@vger.kernel.org
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
There is a bug when migrate from !feature-persistent host to feature-persistent
host, because domU still thinks new host/backend doesn't support persistent.
Dmesg like:
backed has not unmapped grant: 839
backed has not unmapped grant: 773
backed has not unmapped grant: 773
backed has not unmapped grant: 773
backed has not unmapped grant: 839
The fix is to recheck feature-persistent of new backend in blkif_recover().
See: https://lkml.org/lkml/2015/5/25/469
As Roger suggested, we can split the part of blkfront_connect that checks for
optional features, like persistent grants, indirect descriptors and
flush/barrier features to a separate function and call it from both
blkfront_connect and blkif_recover
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
- Add "make xenconfig" to assist in generating configs for Xen guests.
- Preparatory cleanups necessary for supporting 64 KiB pages in ARM
guests.
- Automatically use hvc0 as the default console in ARM guests.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.12 (GNU/Linux)
iQEcBAABAgAGBQJVkpoqAAoJEFxbo/MsZsTRu3IH/2AMPx2i65hoSqfHtGf3sz/z
XNfcidVmOElFVXGaW83m0tBWMemT5LpOGRfiq5sIo8xt/8xD2vozEkl/3kkf3RrX
EmZDw3E8vmstBdBTjWdovVhNenRc0m0pB5daS7wUdo9cETq1ag1L3BHTB3fEBApO
74V6qAfnhnq+snqWhRD3XAk3LKI0nWuWaV+5HsmxDtnunGhuRLGVs7mwxZGg56sM
mILA0eApGPdwyVVpuDe0SwV52V8E/iuVOWTcomGEN2+cRWffG5+QpHxQA8bOtF6O
KfqldiNXOY/idM+5+oSm9hespmdWbyzsFqmTYz0LvQvxE8eEZtHHB3gIcHkE8QU=
=danz
-----END PGP SIGNATURE-----
Merge tag 'for-linus-4.2-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from David Vrabel:
"Xen features and cleanups for 4.2-rc0:
- add "make xenconfig" to assist in generating configs for Xen guests
- preparatory cleanups necessary for supporting 64 KiB pages in ARM
guests
- automatically use hvc0 as the default console in ARM guests"
* tag 'for-linus-4.2-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
block/xen-blkback: s/nr_pages/nr_segs/
block/xen-blkfront: Remove invalid comment
block/xen-blkfront: Remove unused macro MAXIMUM_OUTSTANDING_BLOCK_REQS
arm/xen: Drop duplicate define mfn_to_virt
xen/grant-table: Remove unused macro SPP
xen/xenbus: client: Fix call of virt_to_mfn in xenbus_grant_ring
xen: Include xen/page.h rather than asm/xen/page.h
kconfig: add xenconfig defconfig helper
kconfig: clarify kvmconfig is for kvm
xen/pcifront: Remove usage of struct timeval
xen/tmem: use BUILD_BUG_ON() in favor of BUG_ON()
hvc_xen: avoid uninitialized variable warning
xenbus: avoid uninitialized variable warning
xen/arm: allow console=hvc0 to be omitted for guests
arm,arm64/xen: move Xen initialization earlier
arm/xen: Correctly check if the event channel interrupt is present
Patch 69b91ede5c
"drivers: xen-blkback: delay pending_req allocation to connect_ring"
exposed an problem that Xen blkfront has. There is a race
with XenStored and the drivers such that we can see two:
vbd vbd-268440320: blkfront:blkback_changed to state 2.
vbd vbd-268440320: blkfront:blkback_changed to state 2.
vbd vbd-268440320: blkfront:blkback_changed to state 4.
state changes to XenbusStateInitWait ('2'). The end result is that
blkback_changed() receives two notify and calls twice setup_blkring().
While the backend driver may only get the first setup_blkring() which is
wrong and reads out-dated (or reads them as they are being updated
with new ring-ref values).
The end result is that the ring ends up being incorrectly set.
The other drivers in the tree have such checks already in.
Reported-and-Tested-by: Robert Butera <robert.butera@oracle.com>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Since commit b764915 "xen-blkfront: use a different scatterlist for each
request", biovec has been replaced by scatterlist when copying back the
data during a completion request.
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
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>
Originally Xen PV drivers only use single-page ring to pass along
information. This might limit the throughput between frontend and
backend.
The patch extends Xenbus driver to support multi-page ring, which in
general should improve throughput if ring is the bottleneck. Changes to
various frontend / backend to adapt to the new interface are also
included.
Affected Xen drivers:
* blkfront/back
* netfront/back
* pcifront/back
* scsifront/back
* vtpmfront
The interface is documented, as before, in xenbus_client.c.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Cc: Konrad Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Merge third set of updates from Andrew Morton:
- the rest of MM
[ This includes getting rid of the numa hinting bits, in favor of
just generic protnone logic. Yay. - Linus ]
- core kernel
- procfs
- some of lib/ (lots of lib/ material this time)
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (104 commits)
lib/lcm.c: replace include
lib/percpu_ida.c: remove redundant includes
lib/strncpy_from_user.c: replace module.h include
lib/stmp_device.c: replace module.h include
lib/sort.c: move include inside #if 0
lib/show_mem.c: remove redundant include
lib/radix-tree.c: change to simpler include
lib/plist.c: remove redundant include
lib/nlattr.c: remove redundant include
lib/kobject_uevent.c: remove redundant include
lib/llist.c: remove redundant include
lib/md5.c: simplify include
lib/list_sort.c: rearrange includes
lib/genalloc.c: remove redundant include
lib/idr.c: remove redundant include
lib/halfmd4.c: simplify includes
lib/dynamic_queue_limits.c: simplify includes
lib/sort.c: use simpler includes
lib/interval_tree.c: simplify includes
hexdump: make it return number of bytes placed in buffer
...
__FUNCTION__ hasn't been treated as a string literal since gcc 3.4, so
this only helps people who only test-compile using 3.3 (compiler-gcc3.h
barks at anything older than that). Besides, there are almost no
occurrences of __FUNCTION__ left in the tree.
[akpm@linux-foundation.org: convert remaining __FUNCTION__ references]
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Current migration code uses blk_put_request in order to finish a request
before requeuing it. This function doesn't update the statistics of the
queue, which completely screws accounting. Use blk_end_request_all instead
which properly updates the statistics of the queue.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reported-and-Tested-by: Ouyang Zhaowei (Charles) <ouyangzhaowei@huawei.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: xen-devel@lists.xenproject.org
flush_op is unambiguously defined by feature_flush:
REQ_FUA | REQ_FLUSH -> BLKIF_OP_WRITE_BARRIER
REQ_FLUSH -> BLKIF_OP_FLUSH_DISKCACHE
0 -> 0
and thus can be removed. This is just a cleanup.
The patch was suggested by Boris Ostrovsky.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Guard against issuing unsupported REQ_FUA and REQ_FLUSH was introduced
in d11e61583 and was factored out into blkif_request_flush_valid() in
0f1ca65ee. However:
1) This check in incomplete. In case we negotiated to feature_flush = REQ_FLUSH
and flush_op = BLKIF_OP_FLUSH_DISKCACHE (so FUA is unsupported) FUA request
will still pass the check.
2) blkif_request_flush_valid() is misnamed. It is bool but returns true when
the request is invalid.
3) When blkif_request_flush_valid() fails -EIO is being returned. It seems that
-EOPNOTSUPP is more appropriate here.
Fix all of the above issues.
This patch is based on the original patch by Laszlo Ersek and a comment by
Jeff Moyer.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Pull block layer driver update from Jens Axboe:
"This is the block driver pull request for 3.18. Not a lot in there
this round, and nothing earth shattering.
- A round of drbd fixes from the linbit team, and an improvement in
asender performance.
- Removal of deprecated (and unused) IRQF_DISABLED flag in rsxx and
hd from Michael Opdenacker.
- Disable entropy collection from flash devices by default, from Mike
Snitzer.
- A small collection of xen blkfront/back fixes from Roger Pau Monné
and Vitaly Kuznetsov"
* 'for-3.18/drivers' of git://git.kernel.dk/linux-block:
block: disable entropy contributions for nonrot devices
xen, blkfront: factor out flush-related checks from do_blkif_request()
xen-blkback: fix leak on grant map error path
xen/blkback: unmap all persistent grants when frontend gets disconnected
rsxx: Remove deprecated IRQF_DISABLED
block: hd: remove deprecated IRQF_DISABLED
drbd: use RB_DECLARE_CALLBACKS() to define augment callbacks
drbd: compute the end before rb_insert_augmented()
drbd: Add missing newline in resync progress display in /proc/drbd
drbd: reduce lock contention in drbd_worker
drbd: Improve asender performance
drbd: Get rid of the WORK_PENDING macro
drbd: Get rid of the __no_warn and __cond_lock macros
drbd: Avoid inconsistent locking warning
drbd: Remove superfluous newline from "resync_extents" debugfs entry.
drbd: Use consistent names for all the bi_end_io callbacks
drbd: Use better variable names
The DEFINE_XENBUS_DRIVER() macro looks a bit weird and causes sparse
errors.
Replace the uses with standard structure definitions instead. This is
similar to pci and usb device registration.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
This commit factors out some checks related to the request insertion
path, which can be done in an function instead of by itself.
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Konrad writes:
Please git pull the following branch:
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git stable/for-jens-3.16
which has a bunch of fixes to the Xen block frontend and backend driver
and a new parameter for Xen backend driver - an override (set by the toolstack)
whether to expose the discard support (if disk of course supports it) or not.
In its initial implementation a check for "type" was added, but only phy
and file are handled. This breaks advertised discard support for other
type values such as qdisk.
Fix and simplify this function: If the backend advertises discard
support it is supposed to implement it properly, so enable
feature_discard unconditionally. If the backend advertises the need for
a certain granularity and alignment then propagate both properties to
the blocklayer. The discard-secure property is a boolean, update the code
to reflect that.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This was used in the olden days, back when onions were proper
yellow. Basically it mapped to the current buffer to be
transferred. With highmem being added more than a decade ago,
most drivers map pages out of a bio, and rq->buffer isn't
pointing at anything valid.
Convert old style drivers to just use bio_data().
For the discard payload use case, just reference the page
in the bio.
Signed-off-by: Jens Axboe <axboe@fb.com>
Konrad writes:
Please git pull the following branch:
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git stable/for-jens-3.14
which is based off v3.13-rc6. If you would like me to rebase it on
a different branch/tag I would be more than happy to do so.
The patches are all bug-fixes and hopefully can go in 3.14.
They deal with xen-blkback shutdown and cause memory leaks
as well as shutdown races. They should go to stable tree and if you
are OK with I will ask them to backport those fixes.
There is also a fix to xen-blkfront to deal with unexpected state
transition. And lastly a fix to the header where it was using the
__aligned__ unnecessarily.
Backend drivers shouldn't transistion to CLOSED unless the frontend is
CLOSED. If a backend does transition to CLOSED too soon then the
frontend may not see the CLOSING state and will not properly shutdown.
So, treat an unexpected backend CLOSED state the same as CLOSING.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
