Lars Ellenberg [Mon, 13 Jun 2016 22:26:29 +0000 (00:26 +0200)]
drbd: discard_zeroes_if_aligned allows "thin" resync for discard_zeroes_data=0
Even if discard_zeroes_data != 0,
if discard_zeroes_if_aligned is set, we assume we can reliably
zero-out/discard using the drbd_issue_peer_discard() helper.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Lars Ellenberg [Mon, 13 Jun 2016 22:26:28 +0000 (00:26 +0200)]
drbd: only restart frozen disk io when D_UP_TO_DATE
When re-attaching the local backend device to a C_STANDALONE D_DISKLESS
R_PRIMARY with OND_SUSPEND_IO, we may only resume IO if we recognize the
backend that is being attached as D_UP_TO_DATE.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Lars Ellenberg [Mon, 13 Jun 2016 22:26:27 +0000 (00:26 +0200)]
drbd: if there is no good data accessible, writes should be IO errors
If DRBD lost all path to good data,
and the on-no-data-accessible policy is OND_SUSPEND_IO,
all pending and new IO requests are suspended (will block).
If that setting is OND_IO_ERROR, IO will still be completed.
READ to "clean" areas (e.g. on an D_INCONSISTENT device,
and bitmap indicates a block is already in sync) will succeed.
READ to "unclean" areas (bitmap indicates block is out-of-sync),
will return EIO.
If we are already D_DISKLESS (or D_FAILED), we also return EIO.
Unfortunately, on a former R_PRIMARY C_SYNC_TARGET D_INCONSISTENT,
after replication link loss, new WRITE requests still went through OK.
The would also set the "out-of-sync" bit on their way, so READ after
WRITE would still return EIO. Also, the data generation UUIDs had not
been bumped, we would cause data divergence, without being able to
detect it on the next sync handshake, given the right sequence of events
in a multiple error scenario and "improper" order of recovery actions.
The right thing to do is to return EIO for all new writes,
unless we have access to good, current, D_UP_TO_DATE data.
The "established best practices" way to avoid these situations in the
first place is to set OND_SUSPEND_IO, or even do a hard-reset from
the pri-on-incon-degr policy helper hook.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Lars Ellenberg [Mon, 13 Jun 2016 22:26:26 +0000 (00:26 +0200)]
drbd: don't forget error completion when "unsuspending" IO
Possibly sequence of events:
SyncTarget is made Primary, then loses replication link
(only path to good data on SyncSource).
Behavior is then controlled by the on-no-data-accessible policy,
which defaults to OND_IO_ERROR (may be set to OND_SUSPEND_IO).
If OND_IO_ERROR is in fact the current policy, we clear the susp_fen
(IO suspended due to fencing policy) flag, do NOT set the susp_nod
(IO suspended due to no data) flag.
But we forgot to call the IO error completion for all pending,
suspended, requests.
While at it, also add a race check for a theoretically possible
race with a new handshake (network hickup), we may be able to
re-send requests, and can avoid passing IO errors up the stack.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Lars Ellenberg [Mon, 13 Jun 2016 22:26:25 +0000 (00:26 +0200)]
drbd: introduce unfence-peer handler
When resync is finished, we already call the "after-resync-target"
handler (on the former sync target, obviously), once per volume.
Paired with the before-resync-target handler, you can create snapshots,
before the resync causes the volumes to become inconsistent,
and discard those snapshots again, once they are no longer needed.
It was also overloaded to be paired with the "fence-peer" handler,
to "unfence" once the volumes are up-to-date and known good.
This has some disadvantages, though: we call "fence-peer" for the whole
connection (once for the group of volumes), but would call unfence as
side-effect of after-resync-target once for each volume.
Also, we fence on a (current, or about to become) Primary,
which will later become the sync-source.
Calling unfence only as a side effect of the after-resync-target
handler opens a race window, between a new fence on the Primary
(SyncTarget) and the unfence on the SyncTarget, which is difficult to
close without some kind of "cluster wide lock" in those handlers.
We would not need those handlers if we could still communicate.
Which makes trying to aquire a cluster wide lock from those handlers
seem like a very bad idea.
This introduces the "unfence-peer" handler, which will be called
per connection (once for the group of volumes), just like the fence
handler, only once all volumes are back in sync, and on the SyncSource.
Which is expected to be the node that previously called "fence", the
node that is currently allowed to be Primary, and thus the only node
that could trigger a new "fence" that could race with this unfence.
Which makes us not need any cluster wide synchronization here,
serializing two scripts running on the same node is trivial.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Lars Ellenberg [Mon, 13 Jun 2016 22:26:24 +0000 (00:26 +0200)]
drbd: finish resync on sync source only by notification from sync target
If the replication link breaks exactly during "resync finished" detection,
finishing too early on the sync source could again lead to UUIDs rotated
too fast, and potentially a spurious full resync on next handshake.
Always wait for explicit resync finished state change notification from
the sync target.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Lars Ellenberg [Mon, 13 Jun 2016 22:26:21 +0000 (00:26 +0200)]
drbd: possibly disable discard support, if backend has discard_zeroes_data=0
Now that we have the discard_zeroes_if_aligned setting, we should also
check it when setting up our queue parameters on the primary,
not only on the receiving side.
We announce discard support,
UNLESS
* we are connected to a peer that does not support TRIM
on the DRBD protocol level. Otherwise, it would either discard, or
do a fallback to zero-out, depending on its backend and configuration.
* our local backend does not support discards,
or (discard_zeroes_data=0 AND discard_zeroes_if_aligned=no).
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Lars Ellenberg [Mon, 13 Jun 2016 22:26:20 +0000 (00:26 +0200)]
drbd: when receiving P_TRIM, zero-out partial unaligned chunks
We can avoid spurious data divergence caused by partially-ignored
discards on certain backends with discard_zeroes_data=0, if we
translate partial unaligned discard requests into explicit zero-out.
The relevant use case is LVM/DM thin.
If on different nodes, DRBD is backed by devices with differing
discard characteristics, discards may lead to data divergence
(old data or garbage left over on one backend, zeroes due to
unmapped areas on the other backend). Online verify would now
potentially report tons of spurious differences.
While probably harmless for most use cases (fstrim on a file system),
DRBD cannot have that, it would violate our promise to upper layers
that our data instances on the nodes are identical.
To be correct and play safe (make sure data is identical on both copies),
we would have to disable discard support, if our local backend (on a
Primary) does not support "discard_zeroes_data=true".
We'd also have to translate discards to explicit zero-out on the
receiving (typically: Secondary) side, unless the receiving side
supports "discard_zeroes_data=true".
Which both would allocate those blocks, instead of unmapping them,
in contrast with expectations.
LVM/DM thin does set discard_zeroes_data=0,
because it silently ignores discards to partial chunks.
We can work around this by checking the alignment first.
For unaligned (wrt. alignment and granularity) or too small discards,
we zero-out the initial (and/or) trailing unaligned partial chunks,
but discard all the aligned full chunks.
At least for LVM/DM thin, the result is effectively "discard_zeroes_data=1".
Arguably it should behave this way internally, by default,
and we'll try to make that happen.
But our workaround is still valid for already deployed setups,
and for other devices that may behave this way.
Setting discard-zeroes-if-aligned=yes will allow DRBD to use
discards, and to announce discard_zeroes_data=true, even on
backends that announce discard_zeroes_data=false.
Setting discard-zeroes-if-aligned=no will cause DRBD to always
fall-back to zero-out on the receiving side, and to not even
announce discard capabilities on the Primary, if the respective
backend announces discard_zeroes_data=false.
We used to ignore the discard_zeroes_data setting completely.
To not break established and expected behaviour, and suddenly
cause fstrim on thin-provisioned LVs to run out-of-space,
instead of freeing up space, the default value is "yes".
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Lars Ellenberg [Mon, 13 Jun 2016 22:26:19 +0000 (00:26 +0200)]
drbd: allow parallel flushes for multi-volume resources
To maintain write-order fidelity accros all volumes in a DRBD resource,
the receiver of a P_BARRIER needs to issue flushes to all volumes.
We used to do this by calling blkdev_issue_flush(), synchronously,
one volume at a time.
We now submit all flushes to all volumes in parallel, then wait for all
completions, to reduce worst-case latencies on multi-volume resources.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Lars Ellenberg [Mon, 13 Jun 2016 22:26:18 +0000 (00:26 +0200)]
drbd: fix for truncated minor number in callback command line
The command line parameter the kernel module uses to communicate the
device minor to userland helper is flawed in a way that the device
indentifier "minor-%d" is being truncated to minors with a maximum
of 5 digits.
But DRBD 8.4 allows 2^20 == 1048576 minors,
thus a minimum of 7 digits must be supported.
Reported by Veit Wahlich on drbd-dev.
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Lars Ellenberg [Mon, 13 Jun 2016 22:26:17 +0000 (00:26 +0200)]
drbd: fix regression: protocol A sometimes synchronous, C sometimes double-latency
Regression introduced with 8.4.5
drbd: application writes may set-in-sync in protocol != C
Overwriting the same block (LBA) while a former version is still
"in-flight" to the peer (to be exact: we did not receive the
P_BARRIER_ACK for its epoch yet) would wait for the full epoch of that
former version to be acknowledged by the peer.
In synchronous and quasi-synchronous protocols C and B,
this may double the latency on overwrites.
With protocol A, which is supposed to be asynchronous and only wait for
local completion, it is even worse: it would make overwrites
quasi-synchronous, they would be hit by the full RTT, which protocol A
was specifically meant to avoid, and possibly the additional time it
takes to drain the buffers first.
Particularly bad for databases, or anything else that
does frequent updates to the same blocks (various file system meta data).
No impact if >= rtt passes between updates to the same block.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Philipp Reisner [Mon, 13 Jun 2016 22:26:15 +0000 (00:26 +0200)]
drbd: Create the protocol feature THIN_RESYNC
If thinly provisioned volumes are used, during a resync the sync source
tries to find out if a block is deallocated. If it is deallocated, then
the resync target uses block_dev_issue_zeroout() on the range in
question.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Philipp Reisner [Mon, 13 Jun 2016 22:26:14 +0000 (00:26 +0200)]
drbd: Introduce new disk config option rs-discard-granularity
As long as the value is 0 the feature is disabled. With setting
it to a positive value, DRBD limits and aligns its resync requests
to the rs-discard-granularity setting. If the sync source detects
all zeros in such a block, the resync target discards the range
on disk.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Lars Ellenberg [Mon, 13 Jun 2016 22:26:11 +0000 (00:26 +0200)]
drbd: change bitmap write-out when leaving resync states
When leaving resync states because of disconnect,
do the bitmap write-out synchronously in the drbd_disconnected() path.
When leaving resync states because we go back to AHEAD/BEHIND, or
because resync actually finished, or some disk was lost during resync,
trigger the write-out from after_state_ch().
The bitmap write-out for resync -> ahead/behind was missing completely before.
Note that this is all only an optimization to avoid double-resyncs of
already completed blocks in case this node crashes.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Lars Ellenberg [Mon, 13 Jun 2016 22:26:10 +0000 (00:26 +0200)]
drbd: bitmap bulk IO: do not always suspend IO
The intention was to only suspend IO if some normal bitmap operation is
supposed to be locked out, not always. If the bulk operation is flaged
as BM_LOCKED_CHANGE_ALLOWED, we do not need to suspend IO.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
nvme: move the workaround for I/O queue-less controllers from PCIe to core
We want to apply this to Fabrics drivers as well, so move it to common
code.
Reviewed-by: Jay Freyensee <james.p.freyensee@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Tested-by: Ming Lin <ming.l@ssi.samsung.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Jay Freyensee <james.p.freyensee@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Ming Lin <ming.l@ssi.samsung.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Dedicated workqueues have been used since bcache_wq and moving_gc_wq
are workqueues for writes and are being used on a memory reclaim path.
WQ_MEM_RECLAIM has been set to ensure forward progress under memory
pressure.
Since there are only a fixed number of work items, explicit concurrency
limit is unnecessary here.
block: add a separate operation type for secure erase
Instead of overloading the discard support with the REQ_SECURE flag.
Use the opportunity to rename the queue flag as well, and remove the
dead checks for this flag in the RAID 1 and RAID 10 drivers that don't
claim support for secure erase.
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
Sunad Bhandary [Fri, 27 May 2016 10:29:43 +0000 (15:59 +0530)]
NVMe: Fix removal in case of active namespace list scanning method
In case of the active namespace list scanning method, a namespace that
is detached is not removed from the host if it was the last entry in
the list. Fix this by adding a scan to validate namespaces greater than
the value of prev.
This also handles the case of removing namespaces whose value exceed
the device's reported number of namespaces.
Signed-off-by: Sunad Bhandary S <sunad.s@samsung.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
Ming Lin [Wed, 18 May 2016 21:05:02 +0000 (14:05 -0700)]
nvme: move nvme_cancel_request() to common code
So it can be used by fabrics driver also.
Signed-off-by: Ming Lin <ming.l@samsung.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Keith Busch <keith.bsuch@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Ming Lin [Wed, 18 May 2016 21:05:01 +0000 (14:05 -0700)]
nvme: update and rename nvme_cancel_io to nvme_cancel_request
nvme_cancel_io is a bit confusing (given the distinction of io/admin),
so rename it to nvme_cancel_request.
And update it a bit to pass in struct nvme_ctrl, so it can be used
by Fabrics driver also.
Signed-off-by: Ming Lin <ming.l@samsung.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Suggested-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Keith Busch <keith.bsuch@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:32:25 +0000 (14:32 -0500)]
block, drivers, fs: rename REQ_FLUSH to REQ_PREFLUSH
To avoid confusion between REQ_OP_FLUSH, which is handled by
request_fn drivers, and upper layers requesting the block layer
perform a flush sequence along with possibly a WRITE, this patch
renames REQ_FLUSH to REQ_PREFLUSH.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:32:24 +0000 (14:32 -0500)]
block: do not use REQ_FLUSH for tracking flush support
The last patch added a REQ_OP_FLUSH for request_fn drivers
and the next patch renames REQ_FLUSH to REQ_PREFLUSH which
will be used by file systems and make_request_fn drivers so
they can send a write/flush combo.
This patch drops xen's use of REQ_FLUSH to track if it supports
REQ_OP_FLUSH requests, so REQ_FLUSH can be deleted.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Juergen Gross <kernel@pfupf.net> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:32:23 +0000 (14:32 -0500)]
block, drivers: add REQ_OP_FLUSH operation
This adds a REQ_OP_FLUSH operation that is sent to request_fn
based drivers by the block layer's flush code, instead of
sending requests with the request->cmd_flags REQ_FLUSH bit set.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:32:22 +0000 (14:32 -0500)]
block, fs, drivers: remove REQ_OP compat defs and related code
This patch drops the compat definition of req_op where it matches
the rq_flag_bits definitions, and drops the related old and compat
code that allowed users to set either the op or flags for the operation.
We also then store the operation in the bi_rw/cmd_flags field similar
to how we used to store the bio ioprio where it sat in the upper bits
of the field.
Signed-off-by: Mike Christie <mchristi@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:32:20 +0000 (14:32 -0500)]
block: move bio io prio to a new field
In the next patch, we move drop the compat code and make
the op a separate value that is hidden in bi_rw. To give
the op and rq bits flags room to grow this moves prio to
its own field.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:32:19 +0000 (14:32 -0500)]
ide cd: do not set REQ_WRITE on requests.
The block layer will set the correct READ/WRITE operation flags/fields
when creating a request, so there is not need for drivers to set the
REQ_WRITE flag.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:32:17 +0000 (14:32 -0500)]
drivers: use req op accessor
The req operation REQ_OP is separated from the rq_flag_bits
definition. This converts the block layer drivers to
use req_op to get the op from the request struct.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:32:14 +0000 (14:32 -0500)]
blkg_rwstat: separate op from flags
The bio and request operation and flags are going to be separate
definitions, so we cannot pass them in as a bitmap. This patch
converts the blkg_rwstat code and its caller, cfq, to pass in the
values separately.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:32:12 +0000 (14:32 -0500)]
block: prepare mq request creation to use REQ_OPs
This patch modifies the blk mq request creation code to use
separate variables for the operation and flags, because in the
the next patches the struct request users will be converted like
was done for bios.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:32:11 +0000 (14:32 -0500)]
block: prepare request creation/destruction code to use REQ_OPs
This patch prepares *_get_request/*_put_request and freed_request,
to use separate variables for the operation and flags. In the
next patches the struct request users will be converted like
was done for bios where the op and flags are set separately.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:32:03 +0000 (14:32 -0500)]
dm: pass dm stats data dir instead of bi_rw
It looks like dm stats cares about the data direction
(READ vs WRITE) and does not need the bio/request flags.
Commands like REQ_FLUSH, REQ_DISCARD and REQ_WRITE_SAME
are currently always set with REQ_WRITE, so the extra check for
REQ_DISCARD in dm_stats_account_io is not needed.
This patch has it use the bio and request data_dir helpers
instead of accessing the bi_rw/cmd_flags directly. This makes
the next patches that remove the operation from the cmd_flags
and bi_rw easier, because we will no longer have the REQ_WRITE
bit set for operations like discards.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:31:54 +0000 (14:31 -0500)]
btrfs: use bio fields for op and flags
The bio REQ_OP and bi_rw rq_flag_bits are now always setup, so there is
no need to pass around the rq_flag_bits bits too. btrfs users should
should access the bio insead.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:31:53 +0000 (14:31 -0500)]
btrfs: update __btrfs_map_block for REQ_OP transition
We no longer pass in a bitmap of rq_flag_bits bits to __btrfs_map_block.
It will always be a REQ_OP, or the btrfs specific REQ_GET_READ_MIRRORS,
so this drops the bit tests.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:31:51 +0000 (14:31 -0500)]
btrfs: have submit_one_bio users use bio op accessors
This patch has btrfs's submit_one_bio users set the bio op using
bio_set_op_attrs and get the op using bio_op.
The next patches will continue to convert btrfs,
so submit_bio_hook and merge_bio_hook
related code will be modified to take only the bio. I did
not do it in this patch to try and keep it smaller.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:31:50 +0000 (14:31 -0500)]
direct-io: use bio set/get op accessors
This patch has the dio code use a REQ_OP for the op and rq_flag_bits
for bi_rw flags. To set/get the op it uses the bio_set_op_attrs/bio_op
accssors.
It also begins to convert btrfs's dio_submit_t because of the dio
submit_io callout use. The next patches will completely convert
this code and the reset of the btrfs code paths.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:31:48 +0000 (14:31 -0500)]
block, fs, mm, drivers: use bio set/get op accessors
This patch converts the simple bi_rw use cases in the block,
drivers, mm and fs code to set/get the bio operation using
bio_set_op_attrs/bio_op
These should be simple one or two liner cases, so I just did them
in one patch. The next patches handle the more complicated
cases in a module per patch.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:31:47 +0000 (14:31 -0500)]
bcache: use op_is_write instead of checking for REQ_WRITE
We currently set REQ_WRITE/WRITE for all non READ IOs
like discard, flush, writesame, etc. In the next patches where we
no longer set up the op as a bitmap, we will not be able to
detect a operation direction like writesame by testing if REQ_WRITE is
set.
This has bcache use the op_is_write helper which will do the right
thing.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:31:46 +0000 (14:31 -0500)]
dm: use op_is_write instead of checking for REQ_WRITE
We currently set REQ_WRITE/WRITE for all non READ IOs
like discard, flush, writesame, etc. In the next patches where we
no longer set up the op as a bitmap, we will not be able to
detect a operation direction like writesame by testing if REQ_WRITE is
set.
This has dm use the op_is_write helper which will do the right
thing.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:31:45 +0000 (14:31 -0500)]
block, drivers, cgroup: use op_is_write helper instead of checking for REQ_WRITE
We currently set REQ_WRITE/WRITE for all non READ IOs
like discard, flush, writesame, etc. In the next patches where we
no longer set up the op as a bitmap, we will not be able to
detect a operation direction like writesame by testing if REQ_WRITE is
set.
This patch converts the drivers and cgroup to use the
op_is_write helper. This should just cover the simple
cases. I did dm, md and bcache in their own patches
because they were more involved.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:31:44 +0000 (14:31 -0500)]
fs: have ll_rw_block users pass in op and flags separately
This has ll_rw_block users pass in the operation and flags separately,
so ll_rw_block can setup the bio op and bi_rw flags on the bio that
is submitted.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:31:43 +0000 (14:31 -0500)]
fs: have submit_bh users pass in op and flags separately
This has submit_bh users pass in the operation and flags separately,
so submit_bh_wbc can setup the bio op and bi_rw flags on the bio that
is submitted.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:31:42 +0000 (14:31 -0500)]
block: add REQ_OP definitions and helpers
The following patches separate the operation (WRITE, READ, DISCARD,
etc) from the rq_flag_bits flags. This patch adds definitions for
request/bio operations (REQ_OPs) and adds request/bio accessors to
get/set the op.
In this patch the REQ_OPs match the REQ rq_flag_bits ones
for compat reasons while all the code is converted to use the
op accessors in the set. In the last patches the op will become a
number and the accessors and helpers in this patch will be dropped
or updated.
Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Mike Christie [Sun, 5 Jun 2016 19:31:41 +0000 (14:31 -0500)]
block/fs/drivers: remove rw argument from submit_bio
This has callers of submit_bio/submit_bio_wait set the bio->bi_rw
instead of passing it in. This makes that use the same as
generic_make_request and how we set the other bio fields.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Fixed up fs/ext4/crypto.c
Linus Torvalds [Sun, 5 Jun 2016 18:15:33 +0000 (11:15 -0700)]
Merge branch 'parisc-4.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
Pull parisc fixes from Helge Deller:
- Fix printk time stamps on SMP systems which got wrong due to a patch
which was added during the merge window
- Fix two bugs in the stack backtrace code: Races in module unloading
and possible invalid accesses to memory due to wrong instruction
decoding (Mikulas Patocka)
- Fix userspace crash when syscalls access invalid unaligned userspace
addresses. Those syscalls will now return EFAULT as expected.
(tagged for stable kernel series)
* 'parisc-4.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
parisc: Move die_if_kernel() prototype into traps.h header
parisc: Fix pagefault crash in unaligned __get_user() call
parisc: Fix printk time during boot
parisc: Fix backtrace on PA-RISC
Linus Torvalds [Sun, 5 Jun 2016 18:02:00 +0000 (11:02 -0700)]
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull key handling update from James Morris:
"This alters a new keyctl function added in the current merge window to
allow for a future extension planned for the next merge window"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
KEYS: Add placeholder for KDF usage with DH
devpts: Make each mount of devpts an independent filesystem.
The /dev/ptmx device node is changed to lookup the directory entry "pts"
in the same directory as the /dev/ptmx device node was opened in. If
there is a "pts" entry and that entry is a devpts filesystem /dev/ptmx
uses that filesystem. Otherwise the open of /dev/ptmx fails.
The DEVPTS_MULTIPLE_INSTANCES configuration option is removed, so that
userspace can now safely depend on each mount of devpts creating a new
instance of the filesystem.
Each mount of devpts is now a separate and equal filesystem.
Reserved ttys are now available to all instances of devpts where the
mounter is in the initial mount namespace.
A new vfs helper path_pts is introduced that finds a directory entry
named "pts" in the directory of the passed in path, and changes the
passed in path to point to it. The helper path_pts uses a function
path_parent_directory that was factored out of follow_dotdot.
In the implementation of devpts:
- devpts_mnt is killed as it is no longer meaningful if all mounts of
devpts are equal.
- pts_sb_from_inode is replaced by just inode->i_sb as all cached
inodes in the tty layer are now from the devpts filesystem.
- devpts_add_ref is rolled into the new function devpts_ptmx. And the
unnecessary inode hold is removed.
- devpts_del_ref is renamed devpts_release and reduced to just a
deacrivate_super.
- The newinstance mount option continues to be accepted but is now
ignored.
In devpts_fs.h definitions for when !CONFIG_UNIX98_PTYS are removed as
they are never used.
Documentation/filesystems/devices.txt is updated to describe the current
situation.
This has been verified to work properly on openwrt-15.05, centos5,
centos6, centos7, debian-6.0.2, debian-7.9, debian-8.2, ubuntu-14.04.3,
ubuntu-15.10, fedora23, magia-5, mint-17.3, opensuse-42.1,
slackware-14.1, gentoo-20151225 (13.0?), archlinux-2015-12-01. With the
caveat that on centos6 and on slackware-14.1 that there wind up being
two instances of the devpts filesystem mounted on /dev/pts, the lower
copy does not end up getting used.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Greg KH <greg@kroah.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Peter Anvin <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Serge Hallyn <serge.hallyn@ubuntu.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Aurelien Jarno <aurelien@aurel32.net> Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> Cc: Jann Horn <jann@thejh.net> Cc: Jiri Slaby <jslaby@suse.com> Cc: Florian Weimer <fw@deneb.enyo.de> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This means the userspace program clock_adjtime called the clock_adjtime()
syscall and then crashed inside the compat_get_timex() function.
Syscalls should never crash programs, but instead return EFAULT.
The IIR register contains the executed instruction, which disassebles
into "ldw 0(sr3,r5),r9".
This load-word instruction is part of __get_user() which tried to read the word
at %r5/IOR (0xfa6f7fff). This means the unaligned handler jumped in. The
unaligned handler is able to emulate all ldw instructions, but it fails if it
fails to read the source e.g. because of page fault.
int main(void) {
/* allocate 8k */
char *ptr = mmap(NULL, 2*4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
/* free second half (upper 4k) and make it invalid. */
munmap(ptr+4096, 4096);
/* syscall where first int is unaligned and clobbers into invalid memory region */
/* syscall should return EFAULT */
return syscall(__NR_clock_adjtime, 0, ptr+4095);
}
To fix this issue we simply need to check if the faulting instruction address
is in the exception fixup table when the unaligned handler failed. If it
is, call the fixup routine instead of crashing.
While looking at the unaligned handler I found another issue as well: The
target register should not be modified if the handler was unsuccessful.
Mikulas Patocka [Tue, 28 Jun 2011 22:48:19 +0000 (00:48 +0200)]
parisc: Fix backtrace on PA-RISC
This patch fixes backtrace on PA-RISC
There were several problems:
1) The code that decodes instructions handles instructions that subtract
from the stack pointer incorrectly. If the instruction subtracts the
number X from the stack pointer the code increases the frame size by
(0x100000000-X). This results in invalid accesses to memory and
recursive page faults.
2) Because gcc reorders blocks, handling instructions that subtract from
the frame pointer is incorrect. For example, this function
int f(int a)
{
if (__builtin_expect(a, 1))
return a;
g();
return a;
}
is compiled in such a way, that the code that decreases the stack
pointer for the first "return a" is placed before the code for "g" call.
If we recognize this decrement, we mistakenly believe that the frame
size for the "g" call is zero.
To fix problems 1) and 2), the patch doesn't recognize instructions that
decrease the stack pointer at all. To further safeguard the unwind code
against nonsense values, we don't allow frame size larger than
Total_frame_size.
3) The backtrace is not locked. If stack dump races with module unload,
invalid table can be accessed.
This patch adds a spinlock when processing module tables.
Note, that for correct backtrace, you need recent binutils.
Binutils 2.18 from Debian 5 produce garbage unwind tables.
Binutils 2.21 work better (it sometimes forgets function frames, but at
least it doesn't generate garbage).
Linus Torvalds [Sat, 4 Jun 2016 19:30:36 +0000 (12:30 -0700)]
Merge tag 'drm-fixes-for-v4.7-rc2' of git://people.freedesktop.org/~airlied/linux
Pull drm fixes from Dave Airlie:
"A bunch of ARM drivers got into the fixes vibe this time around, so
this contains a bunch of fixes for imx, atmel hlcdc, arm hdlcd (only
so many combos of hlcd), mediatek and omap drm.
Other than that there is one mgag200 fix and a few core drm regression
fixes"
* tag 'drm-fixes-for-v4.7-rc2' of git://people.freedesktop.org/~airlied/linux: (34 commits)
drm/omap: fix unused variable warning.
drm: hdlcd: Add information about the underlying framebuffers in debugfs
drm: hdlcd: Cleanup the atomic plane operations
drm/hdlcd: Fix up crtc_state->event handling
drm: hdlcd: Revamp runtime power management
drm/mediatek: mtk_dsi: Remove spurious drm_connector_unregister
drm/mediatek: mtk_dpi: remove invalid error message
drm: atmel-hlcdc: fix a NULL check
drm: atmel-hlcdc: fix atmel_hlcdc_crtc_reset() implementation
drm/mgag200: Black screen fix for G200e rev 4
drm: Wrap direct calls to driver->gem_free_object from CMA
drm: fix fb refcount issue with atomic modesetting
drm: make drm_atomic_set_mode_prop_for_crtc() more reliable
drm/sti: remove extra mode fixup
drm: add missing drm_mode_set_crtcinfo call
drm/omap: include gpio/consumer.h where needed
drm/omap: include linux/seq_file.h where needed
Revert "drm/omap: no need to select OMAP2_DSS"
drm/omap: Remove regulator API abuse
OMAPDSS: HDMI5: Change DDC timings
...
Linus Torvalds [Sat, 4 Jun 2016 19:25:36 +0000 (12:25 -0700)]
Merge tag 'vfio-v4.7-rc2' of git://github.com/awilliam/linux-vfio
Pull VFIO fixes from Alex Williamson:
"Fix irqfd shutdown ordering, build warning, and VPD short read"
* tag 'vfio-v4.7-rc2' of git://github.com/awilliam/linux-vfio:
vfio/pci: Allow VPD short read
vfio/type1: Fix build warning
vfio/pci: Fix ordering of eventfd vs virqfd shutdown
Linus Torvalds [Sat, 4 Jun 2016 18:56:28 +0000 (11:56 -0700)]
Merge branch 'for-linus-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs fixes from Chris Mason:
"The important part of this pull is Filipe's set of fixes for btrfs
device replacement. Filipe fixed a few issues seen on the list and a
number he found on his own"
* 'for-linus-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: deal with duplciates during extent_map insertion in btrfs_get_extent
Btrfs: fix race between device replace and read repair
Btrfs: fix race between device replace and discard
Btrfs: fix race between device replace and chunk allocation
Btrfs: fix race setting block group back to RW mode during device replace
Btrfs: fix unprotected assignment of the left cursor for device replace
Btrfs: fix race setting block group readonly during device replace
Btrfs: fix race between device replace and block group removal
Btrfs: fix race between readahead and device replace/removal
Linus Torvalds [Sat, 4 Jun 2016 18:37:53 +0000 (11:37 -0700)]
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
Pull Ceph fixes from Sage Weil:
"We have a few follow-up fixes for the libceph refactor from Ilya, and
then some cephfs + fscache fixes from Zheng.
The first two FS-Cache patches are acked by David Howells and deemed
trivial enough to go through our tree. The rest fix some issues with
the ceph fscache handling (disable cache for inodes opened for write,
and simplify the revalidation logic accordingly, dropping the
now-unnecessary work queue)"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
ceph: use i_version to check validity of fscache
ceph: improve fscache revalidation
ceph: disable fscache when inode is opened for write
ceph: avoid unnecessary fscache invalidation/revlidation
ceph: call __fscache_uncache_page() if readpages fails
FS-Cache: make check_consistency callback return int
FS-Cache: wake write waiter after invalidating writes
libceph: use %s instead of %pE in dout()s
libceph: put request only if it's done in handle_reply()
libceph: change ceph_osdmap_flag() to take osdc
Linus Torvalds [Sat, 4 Jun 2016 18:26:49 +0000 (11:26 -0700)]
Merge tag 'acpi-4.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI fixes from Rafael Wysocki:
"Two fixes for problems introduced recently (ACPICA and the ACPI
backlight driver) and one fix for an older issue that prevents at
least one system from booting.
Specifics:
- Fix an incorrect check introduced by recent ACPICA changes which
causes problems with booting KVM guests to happen, among other
things (Lv Zheng).
- Fix a backlight issue introduced by recent changes to the ACPI
video driver (Aaron Lu).
- Fix the ACPI processor initialization which attempts to register an
IO region without checking if that really is necessary and
sometimes prevents drivers loaded subsequently from registering
their resources which leads to boot issues (Rafael Wysocki)"
* tag 'acpi-4.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI / processor: Avoid reserving IO regions too early
ACPICA / Hardware: Fix old register check in acpi_hw_get_access_bit_width()
ACPI / Thermal / video: fix max_level incorrect value
Linus Torvalds [Sat, 4 Jun 2016 18:07:57 +0000 (11:07 -0700)]
Merge tag 'pm-4.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"Two fixes for problems introduced recently in the cpufreq core and the
intel_pstate driver.
Specifics:
- Fix a silly mistake related to the clamp_val() usage in a function
added by a recent commit (Rafael Wysocki).
- Reduce the log level of an annoying message added to intel_pstate
during the recent merge window (Srinivas Pandruvada)"
* tag 'pm-4.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq: Fix clamp_val() usage in cpufreq_driver_fast_switch()
cpufreq: intel_pstate: Downgrade print level for _PPC
Linus Torvalds [Sat, 4 Jun 2016 17:51:29 +0000 (10:51 -0700)]
Merge branch 'akpm' (patches from Andrew)
Merge various fixes from Andrew Morton:
"10 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
mm, page_alloc: recalculate the preferred zoneref if the context can ignore memory policies
mm, page_alloc: reset zonelist iterator after resetting fair zone allocation policy
mm, oom_reaper: do not use siglock in try_oom_reaper()
mm, page_alloc: prevent infinite loop in buffered_rmqueue()
checkpatch: reduce git commit description style false positives
mm/z3fold.c: avoid modifying HEADLESS page and minor cleanup
memcg: add RCU locking around css_for_each_descendant_pre() in memcg_offline_kmem()
mm: check the return value of lookup_page_ext for all call sites
kdump: fix dmesg gdbmacro to work with record based printk
mm: fix overflow in vm_map_ram()
Linus Torvalds [Fri, 3 Jun 2016 23:12:35 +0000 (16:12 -0700)]
Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fixes from Thomas Gleixner:
- a few simple fixes for fallout from the recent gic-v3 changes
- a workaround for a Cavium thunderX erratum
- a bugfix for the pic32 irqchip to make external interrupts work proper
- a missing return value in the generic IPI management code
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/irq-pic32-evic: Fix bug with external interrupts.
irqchip/gicv3-its: numa: Enable workaround for Cavium thunderx erratum 23144
irqchip/gic-v3: Fix quiescence check in gic_enable_redist
irqchip/gic-v3: Fix copy+paste mistakes in defines
irqchip/gic-v3: Fix ICC_SGI1R_EL1.INTID decoding mask
genirq: Fix missing return value in irq_destroy_ipi()
Mel Gorman [Fri, 3 Jun 2016 21:56:01 +0000 (14:56 -0700)]
mm, page_alloc: recalculate the preferred zoneref if the context can ignore memory policies
The optimistic fast path may use cpuset_current_mems_allowed instead of
of a NULL nodemask supplied by the caller for cpuset allocations. The
preferred zone is calculated on this basis for statistic purposes and as
a starting point in the zonelist iterator.
However, if the context can ignore memory policies due to being atomic
or being able to ignore watermarks then the starting point in the
zonelist iterator is no longer correct. This patch resets the zonelist
iterator in the allocator slowpath if the context can ignore memory
policies. This will alter the zone used for statistics but only after
it is known that it makes sense for that context. Resetting it before
entering the slowpath would potentially allow an ALLOC_CPUSET allocation
to be accounted for against the wrong zone. Note that while nodemask is
not explicitly set to the original nodemask, it would only have been
overwritten if cpuset_enabled() and it was reset before the slowpath was
entered.
Link: http://lkml.kernel.org/r/20160602103936.GU2527@techsingularity.net Fixes: c33d6c06f60f710 ("mm, page_alloc: avoid looking up the first zone in a zonelist twice") Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mel Gorman [Fri, 3 Jun 2016 21:55:58 +0000 (14:55 -0700)]
mm, page_alloc: reset zonelist iterator after resetting fair zone allocation policy
Geert Uytterhoeven reported the following problem that bisected to
commit c33d6c06f60f ("mm, page_alloc: avoid looking up the first zone
in a zonelist twice") on m68k/ARAnyM
The relationship is not obvious but it's due to a failure to rescan the
full zonelist after the fair zone allocation policy exhausts the batch
count. While this is a functional problem, it's also a performance
issue. A page allocator microbenchmark showed the following
4.7.0-rc1 4.7.0-rc1
vanilla reset-v1r2
Min alloc-odr0-1 327.00 ( 0.00%) 326.00 ( 0.31%)
Min alloc-odr0-2 235.00 ( 0.00%) 235.00 ( 0.00%)
Min alloc-odr0-4 198.00 ( 0.00%) 198.00 ( 0.00%)
Min alloc-odr0-8 170.00 ( 0.00%) 170.00 ( 0.00%)
Min alloc-odr0-16 156.00 ( 0.00%) 156.00 ( 0.00%)
Min alloc-odr0-32 150.00 ( 0.00%) 150.00 ( 0.00%)
Min alloc-odr0-64 146.00 ( 0.00%) 146.00 ( 0.00%)
Min alloc-odr0-128 145.00 ( 0.00%) 145.00 ( 0.00%)
Min alloc-odr0-256 155.00 ( 0.00%) 155.00 ( 0.00%)
Min alloc-odr0-512 168.00 ( 0.00%) 165.00 ( 1.79%)
Min alloc-odr0-1024 175.00 ( 0.00%) 174.00 ( 0.57%)
Min alloc-odr0-2048 180.00 ( 0.00%) 180.00 ( 0.00%)
Min alloc-odr0-4096 187.00 ( 0.00%) 186.00 ( 0.53%)
Min alloc-odr0-8192 190.00 ( 0.00%) 190.00 ( 0.00%)
Min alloc-odr0-16384 191.00 ( 0.00%) 191.00 ( 0.00%)
Min alloc-odr1-1 736.00 ( 0.00%) 445.00 ( 39.54%)
Min alloc-odr1-2 343.00 ( 0.00%) 335.00 ( 2.33%)
Min alloc-odr1-4 277.00 ( 0.00%) 270.00 ( 2.53%)
Min alloc-odr1-8 238.00 ( 0.00%) 233.00 ( 2.10%)
Min alloc-odr1-16 224.00 ( 0.00%) 218.00 ( 2.68%)
Min alloc-odr1-32 210.00 ( 0.00%) 208.00 ( 0.95%)
Min alloc-odr1-64 207.00 ( 0.00%) 203.00 ( 1.93%)
Min alloc-odr1-128 276.00 ( 0.00%) 202.00 ( 26.81%)
Min alloc-odr1-256 206.00 ( 0.00%) 202.00 ( 1.94%)
Min alloc-odr1-512 207.00 ( 0.00%) 202.00 ( 2.42%)
Min alloc-odr1-1024 208.00 ( 0.00%) 205.00 ( 1.44%)
Min alloc-odr1-2048 213.00 ( 0.00%) 212.00 ( 0.47%)
Min alloc-odr1-4096 218.00 ( 0.00%) 216.00 ( 0.92%)
Min alloc-odr1-8192 341.00 ( 0.00%) 219.00 ( 35.78%)
Note that order-0 allocations are unaffected but higher orders get a
small boost from this patch and a large reduction in system CPU usage
overall as can be seen here:
4.7.0-rc1 4.7.0-rc1
vanilla reset-v1r2
User 85.32 86.31
System 2221.39 2053.36
Elapsed 2368.89 2202.47
Fixes: c33d6c06f60f ("mm, page_alloc: avoid looking up the first zone in a zonelist twice") Link: http://lkml.kernel.org/r/20160531100848.GR2527@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Mikulas Patocka <mpatocka@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
projects / mirror_ubuntu-zesty-kernel.git / log