02 Mar, 2017

2 commits


07 Nov, 2015

1 commit

  • __GFP_WAIT was used to signal that the caller was in atomic context and
    could not sleep. Now it is possible to distinguish between true atomic
    context and callers that are not willing to sleep. The latter should
    clear __GFP_DIRECT_RECLAIM so kswapd will still wake. As clearing
    __GFP_WAIT behaves differently, there is a risk that people will clear the
    wrong flags. This patch renames __GFP_WAIT to __GFP_RECLAIM to clearly
    indicate what it does -- setting it allows all reclaim activity, clearing
    them prevents it.

    [akpm@linux-foundation.org: fix build]
    [akpm@linux-foundation.org: coding-style fixes]
    Signed-off-by: Mel Gorman
    Acked-by: Michal Hocko
    Acked-by: Vlastimil Babka
    Acked-by: Johannes Weiner
    Cc: Christoph Lameter
    Acked-by: David Rientjes
    Cc: Vitaly Wool
    Cc: Rik van Riel
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Mel Gorman
     

13 Feb, 2015

1 commit

  • These three #includes seem to be completely redundant: Removing them
    yields identical objdump -d output for each of {allyes,allno,def}config,
    and neither included file end up in the generated dependency file through
    some recursive include. In total, about 50 lines are eliminated from
    .percpu.o.cmd.

    Signed-off-by: Rasmus Villemoes
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Rasmus Villemoes
     

15 Feb, 2014

1 commit

  • Pull block IO fixes from Jens Axboe:
    "Second round of updates and fixes for 3.14-rc2. Most of this stuff
    has been queued up for a while. The notable exception is the blk-mq
    changes, which are naturally a bit more in flux still.

    The pull request contains:

    - Two bug fixes for the new immutable vecs, causing crashes with raid
    or swap. From Kent.

    - Various blk-mq tweaks and fixes from Christoph. A fix for
    integrity bio's from Nic.

    - A few bcache fixes from Kent and Darrick Wong.

    - xen-blk{front,back} fixes from David Vrabel, Matt Rushton, Nicolas
    Swenson, and Roger Pau Monne.

    - Fix for a vec miscount with integrity vectors from Martin.

    - Minor annotations or fixes from Masanari Iida and Rashika Kheria.

    - Tweak to null_blk to do more normal FIFO processing of requests
    from Shlomo Pongratz.

    - Elevator switching bypass fix from Tejun.

    - Softlockup in blkdev_issue_discard() fix when !CONFIG_PREEMPT from
    me"

    * 'for-linus' of git://git.kernel.dk/linux-block: (31 commits)
    block: add cond_resched() to potentially long running ioctl discard loop
    xen-blkback: init persistent_purge_work work_struct
    blk-mq: pair blk_mq_start_request / blk_mq_requeue_request
    blk-mq: dont assume rq->errors is set when returning an error from ->queue_rq
    block: Fix cloning of discard/write same bios
    block: Fix type mismatch in ssize_t_blk_mq_tag_sysfs_show
    blk-mq: rework flush sequencing logic
    null_blk: use blk_complete_request and blk_mq_complete_request
    virtio_blk: use blk_mq_complete_request
    blk-mq: rework I/O completions
    fs: Add prototype declaration to appropriate header file include/linux/bio.h
    fs: Mark function as static in fs/bio-integrity.c
    block/null_blk: Fix completion processing from LIFO to FIFO
    block: Explicitly handle discard/write same segments
    block: Fix nr_vecs for inline integrity vectors
    blk-mq: Add bio_integrity setup to blk_mq_make_request
    blk-mq: initialize sg_reserved_size
    blk-mq: handle dma_drain_size
    blk-mq: divert __blk_put_request for MQ ops
    blk-mq: support at_head inserations for blk_execute_rq
    ...

    Linus Torvalds
     

31 Jan, 2014

1 commit

  • steal_tags only happens when free tags is more than half of the total
    tags. This is too strict and can cause live lock. I found that if one
    cpu has free tags, but other cpu can't steal (thread is bound to
    specific cpus), threads which want to allocate tags are always
    sleeping. I found this when I run next patch, but this could happen
    without it I think.

    I did performance test too with null_blk. Two cases (each cpu has enough
    percpu tags, or total tags are limited), no performance changes were
    observed.

    Signed-off-by: Shaohua Li
    Signed-off-by: Jens Axboe

    Shaohua Li
     

25 Jan, 2014

1 commit

  • This patch addresses a bug where connection reset would hang
    indefinately once percpu_ida_alloc() was starved for tags, due
    to the fact that it always assumed uninterruptible sleep mode.

    So now make percpu_ida_alloc() check for signal_pending_state() for
    making interruptible sleep optional, and convert iscsit_allocate_cmd()
    to set TASK_INTERRUPTIBLE for GFP_KERNEL, or TASK_RUNNING for
    GFP_ATOMIC.

    Reported-by: Linus Torvalds
    Cc: Kent Overstreet
    Cc: #3.12+
    Signed-off-by: Nicholas Bellinger

    Nicholas Bellinger
     

24 Jan, 2014

1 commit

  • This patch changes percpu_ida_alloc() + callers to accept task state
    bitmask for prepare_to_wait() for code like target/iscsi that needs
    it for interruptible sleep, that is provided in a subsequent patch.

    It now expects TASK_UNINTERRUPTIBLE when the caller is able to sleep
    waiting for a new tag, or TASK_RUNNING when the caller cannot sleep,
    and is forced to return a negative value when no tags are available.

    v2 changes:
    - Include blk-mq + tcm_fc + vhost/scsi + target/iscsi changes
    - Drop signal_pending_state() call
    v3 changes:
    - Only call prepare_to_wait() + finish_wait() when != TASK_RUNNING
    (PeterZ)

    Reported-by: Linus Torvalds
    Cc: Linus Torvalds
    Cc: Ingo Molnar
    Cc: Peter Zijlstra
    Cc: Jens Axboe
    Signed-off-by: Kent Overstreet
    Cc: #3.12+
    Signed-off-by: Nicholas Bellinger

    Kent Overstreet
     

23 Nov, 2013

1 commit

  • Pull SCSI target updates from Nicholas Bellinger:
    "Things have been quiet this round with mostly bugfixes, percpu
    conversions, and other minor iscsi-target conformance testing changes.

    The highlights include:

    - Add demo_mode_discovery attribute for iscsi-target (Thomas)
    - Convert tcm_fc(FCoE) to use percpu-ida pre-allocation
    - Add send completion interrupt coalescing for ib_isert
    - Convert target-core to use percpu-refcounting for se_lun
    - Fix mutex_trylock usage bug in iscsit_increment_maxcmdsn
    - tcm_loop updates (Hannes)
    - target-core ALUA cleanups + prep for v3.14 SCSI Referrals support (Hannes)

    v3.14 is currently shaping to be a busy development cycle in target
    land, with initial support for T10 Referrals and T10 DIF currently on
    the roadmap"

    * 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (40 commits)
    iscsi-target: chap auth shouldn't match username with trailing garbage
    iscsi-target: fix extract_param to handle buffer length corner case
    iscsi-target: Expose default_erl as TPG attribute
    target_core_configfs: split up ALUA supported states
    target_core_alua: Make supported states configurable
    target_core_alua: Store supported ALUA states
    target_core_alua: Rename ALUA_ACCESS_STATE_OPTIMIZED
    target_core_alua: spellcheck
    target core: rename (ex,im)plict -> (ex,im)plicit
    percpu-refcount: Add percpu-refcount.o to obj-y
    iscsi-target: Do not reject non-immediate CmdSNs exceeding MaxCmdSN
    iscsi-target: Convert iscsi_session statistics to atomic_long_t
    target: Convert se_device statistics to atomic_long_t
    target: Fix delayed Task Aborted Status (TAS) handling bug
    iscsi-target: Reject unsupported multi PDU text command sequence
    ib_isert: Avoid duplicate iscsit_increment_maxcmdsn call
    iscsi-target: Fix mutex_trylock usage in iscsit_increment_maxcmdsn
    target: Core does not need blkdev.h
    target: Pass through I/O topology for block backstores
    iser-target: Avoid using FRMR for single dma entry requests
    ...

    Linus Torvalds
     

25 Oct, 2013

3 commits

  • Add an API to return free tags, blk-mq-tag will use it.

    Note, this just returns a snapshot of free tags number. blk-mq-tag has
    two usages of it. One is for info output for diagnosis. The other is to
    quickly check if there are free tags for request dispatch checking.
    Neither requires very precise.

    Cc: Andrew Morton
    Signed-off-by: Shaohua Li
    Signed-off-by: Jens Axboe

    Shaohua Li
     
  • Add a new API to iterate free ids. blk-mq-tag will use it.

    Note, this doesn't guarantee to iterate all free ids restrictly. Caller
    should be aware of this. blk-mq uses it to do sanity check for request
    timedout, so can tolerate the limitation.

    Cc: Andrew Morton
    Signed-off-by: Shaohua Li
    Signed-off-by: Jens Axboe

    Shaohua Li
     
  • Make percpu_ida percpu size/batch configurable. The block-mq-tag will
    use it.

    After block-mq uses percpu_ida to manage tags, performance is improved.
    My test is done in a 2 sockets machine, 12 process cross the 2 sockets.
    So if there is lock contention or ipi, should be stressed heavily.
    Testing is done for null-blk.

    hw_queue_depth nopatch iops patch iops
    64 ~800k/s ~1470k/s
    2048 ~4470k/s ~4340k/s

    Cc: Andrew Morton
    Signed-off-by: Shaohua Li
    Signed-off-by: Jens Axboe

    Shaohua Li
     

03 Oct, 2013

1 commit


10 Sep, 2013

1 commit

  • Percpu frontend for allocating ids. With percpu allocation (that works),
    it's impossible to guarantee it will always be possible to allocate all
    nr_tags - typically, some will be stuck on a remote percpu freelist
    where the current job can't get to them.

    We do guarantee that it will always be possible to allocate at least
    (nr_tags / 2) tags - this is done by keeping track of which and how many
    cpus have tags on their percpu freelists. On allocation failure if
    enough cpus have tags that there could potentially be (nr_tags / 2) tags
    stuck on remote percpu freelists, we then pick a remote cpu at random to
    steal from.

    Note that there's no cpu hotplug notifier - we don't care, because
    steal_tags() will eventually get the down cpu's tags. We _could_ satisfy
    more allocations if we had a notifier - but we'll still meet our
    guarantees and it's absolutely not a correctness issue, so I don't think
    it's worth the extra code.

    From akpm:

    "It looks OK to me (that's as close as I get to an ack :))

    v6 changes:
    - Add #include to include/linux/percpu_ida.h to
    make alpha/arc builds happy (Fengguang)
    - Move second (cpu >= nr_cpu_ids) check inside of first check scope
    in steal_tags() (akpm + nab)

    v5 changes:
    - Change percpu_ida->cpus_have_tags to cpumask_t (kmo + akpm)
    - Add comment for percpu_ida_cpu->lock + ->nr_free (kmo + akpm)
    - Convert steal_tags() to use cpumask_weight() + cpumask_next() +
    cpumask_first() + cpumask_clear_cpu() (kmo + akpm)
    - Add comment for alloc_global_tags() (kmo + akpm)
    - Convert percpu_ida_alloc() to use cpumask_set_cpu() (kmo + akpm)
    - Convert percpu_ida_free() to use cpumask_set_cpu() (kmo + akpm)
    - Drop percpu_ida->cpus_have_tags allocation in percpu_ida_init()
    (kmo + akpm)
    - Drop percpu_ida->cpus_have_tags kfree in percpu_ida_destroy()
    (kmo + akpm)
    - Add comment for percpu_ida_alloc @ gfp (kmo + akpm)
    - Move to percpu_ida.c + percpu_ida.h (kmo + akpm + nab)

    v4 changes:

    - Fix tags.c reference in percpu_ida_init (akpm)

    Signed-off-by: Kent Overstreet
    Cc: Tejun Heo
    Cc: Oleg Nesterov
    Cc: Christoph Lameter
    Cc: Ingo Molnar
    Cc: Andi Kleen
    Cc: Jens Axboe
    Cc: "Nicholas A. Bellinger"
    Signed-off-by: Nicholas Bellinger

    Kent Overstreet