19 Mar, 2014
1 commit
-
cftype->write_string() just passes on the writeable buffer from kernfs
and there's no reason to add const restriction on the buffer. The
only thing const achieves is unnecessarily complicating parsing of the
buffer. Drop const from @buffer.Signed-off-by: Tejun Heo
Acked-by: Li Zefan
Cc: Peter Zijlstra
Cc: Paul Mackerras
Cc: Ingo Molnar
Cc: Arnaldo Carvalho de Melo
Cc: Daniel Borkmann
Cc: Michal Hocko
Cc: Johannes Weiner
Cc: Balbir Singh
Cc: KAMEZAWA Hiroyuki
12 Feb, 2014
1 commit
-
cftype->max_write_len is used to extend the maximum size of writes.
It's interpreted in such a way that the actual maximum size is one
less than the specified value. The default size is defined by
CGROUP_LOCAL_BUFFER_SIZE. Its interpretation is quite confusing - its
value is decremented by 1 and then compared for equality with max
size, which means that the actual default size is
CGROUP_LOCAL_BUFFER_SIZE - 2, which is 62 chars.There's no point in having a limit that low. Update its definition so
that it means the actual string length sans termination and anything
below PAGE_SIZE-1 is treated as PAGE_SIZE-1..max_write_len for "release_agent" is updated to PATH_MAX-1 and
cgroup_release_agent_write() is updated so that the redundant strlen()
check is removed and it uses strlcpy() instead of strcpy().
.max_write_len initializations in blk-throttle.c and cfq-iosched.c are
no longer necessary and removed. The one in cpuset is kept unchanged
as it's an approximated value to begin with.This will also make transition to kernfs smoother.
Signed-off-by: Tejun Heo
Acked-by: Li Zefan
31 Jan, 2014
1 commit
-
Pull core block IO changes from Jens Axboe:
"The major piece in here is the immutable bio_ve series from Kent, the
rest is fairly minor. It was supposed to go in last round, but
various issues pushed it to this release instead. The pull request
contains:- Various smaller blk-mq fixes from different folks. Nothing major
here, just minor fixes and cleanups.- Fix for a memory leak in the error path in the block ioctl code
from Christian Engelmayer.- Header export fix from CaiZhiyong.
- Finally the immutable biovec changes from Kent Overstreet. This
enables some nice future work on making arbitrarily sized bios
possible, and splitting more efficient. Related fixes to immutable
bio_vecs:- dm-cache immutable fixup from Mike Snitzer.
- btrfs immutable fixup from Muthu Kumar.- bio-integrity fix from Nic Bellinger, which is also going to stable"
* 'for-3.14/core' of git://git.kernel.dk/linux-block: (44 commits)
xtensa: fixup simdisk driver to work with immutable bio_vecs
block/blk-mq-cpu.c: use hotcpu_notifier()
blk-mq: for_each_* macro correctness
block: Fix memory leak in rw_copy_check_uvector() handling
bio-integrity: Fix bio_integrity_verify segment start bug
block: remove unrelated header files and export symbol
blk-mq: uses page->list incorrectly
blk-mq: use __smp_call_function_single directly
btrfs: fix missing increment of bi_remaining
Revert "block: Warn and free bio if bi_end_io is not set"
block: Warn and free bio if bi_end_io is not set
blk-mq: fix initializing request's start time
block: blk-mq: don't export blk_mq_free_queue()
block: blk-mq: make blk_sync_queue support mq
block: blk-mq: support draining mq queue
dm cache: increment bi_remaining when bi_end_io is restored
block: fixup for generic bio chaining
block: Really silence spurious compiler warnings
block: Silence spurious compiler warnings
block: Kill bio_pair_split()
...
06 Dec, 2013
1 commit
-
In preparation of conversion to kernfs, cgroup file handling is
updated so that it can be easily mapped to kernfs. This patch
replaces cftype->read_seq_string() with cftype->seq_show() which is
not limited to single_open() operation and will map directcly to
kernfs seq_file interface.The conversions are mechanical. As ->seq_show() doesn't have @css and
@cft, the functions which make use of them are converted to use
seq_css() and seq_cft() respectively. In several occassions, e.f. if
it has seq_string in its name, the function name is updated to fit the
new method better.This patch does not introduce any behavior changes.
Signed-off-by: Tejun Heo
Acked-by: Aristeu Rozanski
Acked-by: Vivek Goyal
Acked-by: Michal Hocko
Acked-by: Daniel Wagner
Acked-by: Li Zefan
Cc: Jens Axboe
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Johannes Weiner
Cc: Balbir Singh
Cc: KAMEZAWA Hiroyuki
Cc: Neil Horman
24 Nov, 2013
1 commit
-
Immutable biovecs are going to require an explicit iterator. To
implement immutable bvecs, a later patch is going to add a bi_bvec_done
member to this struct; for now, this patch effectively just renames
things.Signed-off-by: Kent Overstreet
Cc: Jens Axboe
Cc: Geert Uytterhoeven
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: "Ed L. Cashin"
Cc: Nick Piggin
Cc: Lars Ellenberg
Cc: Jiri Kosina
Cc: Matthew Wilcox
Cc: Geoff Levand
Cc: Yehuda Sadeh
Cc: Sage Weil
Cc: Alex Elder
Cc: ceph-devel@vger.kernel.org
Cc: Joshua Morris
Cc: Philip Kelleher
Cc: Rusty Russell
Cc: "Michael S. Tsirkin"
Cc: Konrad Rzeszutek Wilk
Cc: Jeremy Fitzhardinge
Cc: Neil Brown
Cc: Alasdair Kergon
Cc: Mike Snitzer
Cc: dm-devel@redhat.com
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: linux390@de.ibm.com
Cc: Boaz Harrosh
Cc: Benny Halevy
Cc: "James E.J. Bottomley"
Cc: Greg Kroah-Hartman
Cc: "Nicholas A. Bellinger"
Cc: Alexander Viro
Cc: Chris Mason
Cc: "Theodore Ts'o"
Cc: Andreas Dilger
Cc: Jaegeuk Kim
Cc: Steven Whitehouse
Cc: Dave Kleikamp
Cc: Joern Engel
Cc: Prasad Joshi
Cc: Trond Myklebust
Cc: KONISHI Ryusuke
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Ben Myers
Cc: xfs@oss.sgi.com
Cc: Steven Rostedt
Cc: Frederic Weisbecker
Cc: Ingo Molnar
Cc: Len Brown
Cc: Pavel Machek
Cc: "Rafael J. Wysocki"
Cc: Herton Ronaldo Krzesinski
Cc: Ben Hutchings
Cc: Andrew Morton
Cc: Guo Chao
Cc: Tejun Heo
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Cc: Wei Yongjun
Cc: "Roger Pau Monné"
Cc: Jan Beulich
Cc: Stefano Stabellini
Cc: Ian Campbell
Cc: Sebastian Ott
Cc: Christian Borntraeger
Cc: Minchan Kim
Cc: Jiang Liu
Cc: Nitin Gupta
Cc: Jerome Marchand
Cc: Joe Perches
Cc: Peng Tao
Cc: Andy Adamson
Cc: fanchaoting
Cc: Jie Liu
Cc: Sunil Mushran
Cc: "Martin K. Petersen"
Cc: Namjae Jeon
Cc: Pankaj Kumar
Cc: Dan Magenheimer
Cc: Mel Gorman 6
13 Nov, 2013
1 commit
-
Now that seqcounts are lockdep enabled objects, we need to explicitly
initialize runtime allocated seqcounts so that lockdep can track them.Without this patch, Fengguang was seeing:
[ 4.127282] INFO: trying to register non-static key.
[ 4.128027] the code is fine but needs lockdep annotation.
[ 4.128027] turning off the locking correctness validator.
[ 4.128027] CPU: 0 PID: 96 Comm: kworker/u4:1 Not tainted 3.12.0-next-20131108-10601-gbad570d #2
[ 4.128027] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ ... ]
[ 4.128027] Call Trace:
[ 4.128027] [] ? console_unlock+0x353/0x380
[ 4.128027] [] dump_stack+0x48/0x60
[ 4.128027] [] __lock_acquire.isra.26+0x7e3/0xceb
[ 4.128027] [] lock_acquire+0x71/0x9a
[ 4.128027] [] ? blk_throtl_bio+0x1c3/0x485
[ 4.128027] [] throtl_update_dispatch_stats+0x7c/0x153
[ 4.128027] [] ? blk_throtl_bio+0x1c3/0x485
[ 4.128027] [] blk_throtl_bio+0x1c3/0x485
...Use u64_stats_init() for all affected data structures, which initializes
the seqcount.Reported-and-Tested-by: Fengguang Wu
Cc: Vivek Goyal
Cc: Jens Axboe
Signed-off-by: Peter Zijlstra
[ Folded in another fix from the mailing list as well as a fix to that fix. Tweaked commit message. ]
Signed-off-by: John Stultz
Signed-off-by: Peter Zijlstra
Link: http://lkml.kernel.org/r/1384314134-6895-1-git-send-email-john.stultz@linaro.org
[ So I actually think that the two SOBs from PeterZ are the right depiction of the patch route. ]
Signed-off-by: Ingo Molnar
09 Aug, 2013
3 commits
-
Previously, all css descendant iterators didn't include the origin
(root of subtree) css in the iteration. The reasons were maintaining
consistency with css_for_each_child() and that at the time of
introduction more use cases needed skipping the origin anyway;
however, given that css_is_descendant() considers self to be a
descendant, omitting the origin css has become more confusing and
looking at the accumulated use cases rather clearly indicates that
including origin would result in simpler code overall.While this is a change which can easily lead to subtle bugs, cgroup
API including the iterators has recently gone through major
restructuring and no out-of-tree changes will be applicable without
adjustments making this a relatively acceptable opportunity for this
type of change.The conversions are mostly straight-forward. If the iteration block
had explicit origin handling before or after, it's moved inside the
iteration. If not, if (pos == origin) continue; is added. Some
conversions add extra reference get/put around origin handling by
consolidating origin handling and the rest. While the extra ref
operations aren't strictly necessary, this shouldn't cause any
noticeable difference.Signed-off-by: Tejun Heo
Acked-by: Li Zefan
Acked-by: Vivek Goyal
Acked-by: Aristeu Rozanski
Acked-by: Michal Hocko
Cc: Jens Axboe
Cc: Matt Helsley
Cc: Johannes Weiner
Cc: Balbir Singh -
cgroup is currently in the process of transitioning to using css
(cgroup_subsys_state) as the primary handle instead of cgroup in
subsystem API. For hierarchy iterators, this is beneficial because* In most cases, css is the only thing subsystems care about anyway.
* On the planned unified hierarchy, iterations for different
subsystems will need to skip over different subtrees of the
hierarchy depending on which subsystems are enabled on each cgroup.
Passing around css makes it unnecessary to explicitly specify the
subsystem in question as css is intersection between cgroup and
subsystem* For the planned unified hierarchy, css's would need to be created
and destroyed dynamically independent from cgroup hierarchy. Having
cgroup core manage css iteration makes enforcing deref rules a lot
easier.Most subsystem conversions are straight-forward. Noteworthy changes
are* blkio: cgroup_to_blkcg() is no longer used. Removed.
* freezer: cgroup_freezer() is no longer used. Removed.
* devices: cgroup_to_devcgroup() is no longer used. Removed.
Signed-off-by: Tejun Heo
Acked-by: Li Zefan
Acked-by: Michal Hocko
Acked-by: Vivek Goyal
Acked-by: Aristeu Rozanski
Cc: Johannes Weiner
Cc: Balbir Singh
Cc: Matt Helsley
Cc: Jens Axboe -
cgroup is currently in the process of transitioning to using struct
cgroup_subsys_state * as the primary handle instead of struct cgroup.
Please see the previous commit which converts the subsystem methods
for rationale.This patch converts all cftype file operations to take @css instead of
@cgroup. cftypes for the cgroup core files don't have their subsytem
pointer set. These will automatically use the dummy_css added by the
previous patch and can be converted the same way.Most subsystem conversions are straight forwards but there are some
interesting ones.* freezer: update_if_frozen() is also converted to take @css instead
of @cgroup for consistency. This will make the code look simpler
too once iterators are converted to use css.* memory/vmpressure: mem_cgroup_from_css() needs to be exported to
vmpressure while mem_cgroup_from_cont() can be made static.
Updated accordingly.* cpu: cgroup_tg() doesn't have any user left. Removed.
* cpuacct: cgroup_ca() doesn't have any user left. Removed.
* hugetlb: hugetlb_cgroup_form_cgroup() doesn't have any user left.
Removed.* net_cls: cgrp_cls_state() doesn't have any user left. Removed.
Signed-off-by: Tejun Heo
Acked-by: Li Zefan
Acked-by: Michal Hocko
Acked-by: Vivek Goyal
Acked-by: Aristeu Rozanski
Acked-by: Daniel Wagner
Cc: Peter Zijlstra
Cc: Ingo Molnar
Cc: Johannes Weiner
Cc: Balbir Singh
Cc: Matt Helsley
Cc: Jens Axboe
Cc: Steven Rostedt
15 May, 2013
28 commits
-
With the recent updates, blk-throttle is finally ready for proper
hierarchy support. Dispatching now honors service_queue->parent_sq
and propagates correctly. The only thing missing is setting
->parent_sq correctly so that throtl_grp hierarchy matches the cgroup
hierarchy.This patch updates throtl_pd_init() such that service_queues form the
same hierarchy as the cgroup hierarchy if sane_behavior is enabled.
As this concludes proper hierarchy support for blkcg, the shameful
.broken_hierarchy tag is removed from blkio_subsys.v2: Updated blkio-controller.txt as suggested by Vivek.
Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal
Cc: Li Zefan -
blk_throtl_bio() has a quick exit path for throtl_grps without limits
configured. It looks at the bps and iops limits and if both are not
configured, the bio is issued immediately. While this is correct in
the current flat hierarchy as each throtl_grp behaves completely
independently, it would become wrong in proper hierarchy mode. A
group without any limits could still be limited by one of its
ancestors and bio's queued for such group should not bypass
blk-throtl.As having a quick bypass mechanism is beneficial, this patch
reimplements the mechanism such that it's correct even with proper
hierarchy. throtl_grp->has_rules[] is added. These booleans are
updated for the whole subtree whenever a config is updated so that
has_rules[] of the whole subtree stays synchronized. They're also
updated when a new throtl_grp comes online so that it can't escape the
limits of its ancestors.As no throtl_grp has another throtl_grp as parent now, this patch
doesn't yet make any behavior differences.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
With the planned proper hierarchy support, a bio will climb up the
tree before actually being dispatched. This makes sure bio is also
subjected to parent's throttling limits, if any.It might happen that parent is idle and when bio is transferred to
parent, a new slice starts fresh. But that is incorrect as parents
wait time should have started when bio was queued in child group and
causes IOs to be throttled more than configured as they climb the
hierarchy.Given the fact that we have not written hierarchical algorithm in a
way where child's and parents time slices are synchronized, we
transfer the child's start time to parent if parent was idling. If
parent was busy doing dispatch of other bios all this while, this is
not an issue.Child's slice start time is passed to parent. Parent looks at its
last expired slice start time. If child's start time is after parents
old start time, that means parent had been idle and after parent
went idle, child had an IO queued. So use child's start time as
parent start time.If parent's start time is after child's start time, that means,
when IO got queued in child group, parent was not idle. But later
it dispatched some IO, its slice got trimmed and then it went idle.
After a while child's request got shifted in parent group. In this
case use parent's old start time as new start time as that's the
duration of slice we did not use.This logic is far from perfect as if there are multiple childs
then first child transferring the bio decides the start time while
a bio might have queued up even earlier in other child, which is
yet to be transferred up to parent. In that case we will lose
time and bandwidth in parent. This patch is just an approximation
to make situation somewhat better.Signed-off-by: Vivek Goyal
Signed-off-by: Tejun Heo -
With flat hierarchy, there's only single level of dispatching
happening and fairness beyond that point is the responsibility of the
rest of the block layer and driver, which usually works out okay;
however, with the planned hierarchy support,
service_queue->bio_lists[] can be filled up by bios from a single
source. While the limits would still be honored, it'd be very easy to
starve IOs from siblings or children.To avoid such starvation, this patch implements throtl_qnode and
converts service_queue->bio_lists[] to lists of per-source qnodes
which in turn contains the bio's. For example, when a bio is
dispatched from a child group, the bio doesn't get queued on
->bio_lists[] directly but it first gets queued on the group's qnode
which in turn gets queued on service_queue->queued[]. When
dispatching for the upper level, the ->queued[] list is consumed in
round-robing order so that the dispatch windows is consumed fairly by
all IO sources.There are two ways a bio can come to a throtl_grp - directly queued to
the group or dispatched from a child. For the former
throtl_grp->qnode_on_self[rw] is used. For the latter, the child's
->qnode_on_parent[rw].Note that this means that the child which is contributing a bio to its
parent should stay pinned until all its bios are dispatched to its
grand-parent. This patch moves blkg refcnting from bio add/remove
spots to qnode activation/deactivation so that the blkg containing an
active qnode is always pinned. As child pins the parent, this is
sufficient for keeping the relevant sub-tree pinned while bios are in
flight.The starvation issue was spotted by Vivek Goyal.
v2: The original patch used the same throtl_grp->qnode_on_self/parent
for reads and writes causing RWs to be queued incorrectly if there
already are outstanding IOs in the other direction. They should
be throtl_grp->qnode_on_self/parent[2] so that READs and WRITEs
can use different qnodes. Spotted by Vivek Goyal.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
throtl_pending_timer_fn() currently assumes that the parent_sq is the
top level one and the bio's dispatched are ready to be issued;
however, this assumption will be wrong with proper hierarchy support.
This patch makes the following changes to make
throtl_pending_timer_fn() ready for hiearchy.* If the parent_sq isn't the top-level one, update the parent
throtl_grp's dispatch time and schedule the next dispatch as
necessary. If the parent's dispatch time is now, repeat the
function for the parent throtl_grp.* If the parent_sq is the top-level one, kick issue work_item as
before.* The debug message printed by throtl_log() now prints out the
service_queue's nr_queued[] instead of the total nr_queued as the
latter becomes uninteresting and misleading with hierarchical
dispatch.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
tg_dispatch_one_bio() currently assumes that the parent_sq is the top
level one and the bio being dispatched is ready to be issued; however,
this assumption will be wrong with proper hierarchy support. This
patch makes the following changes to make tg_dispatch_on_bio() ready
for hiearchy.* throtl_data->nr_queued[] is incremented in blk_throtl_bio() instead
of throtl_add_bio_tg() so that throtl_add_bio_tg() can be used to
transfer a bio from a child tg to its parent.* tg_dispatch_one_bio() is updated to distinguish whether its parent
is another throtl_grp or the throtl_data. If former, the bio is
transferred to the parent throtl_grp using throtl_add_bio_tg(). If
latter, the bio is ready to be issued and put on the top-level
service_queue's bio_lists[] and throtl_data->nr_queued is
decremented.As all throtl_grps currently have the top level service_queue as their
->parent_sq, this patch in itself doesn't make any behavior
difference.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
Currently, blk_throtl_bio() issues the passed in bio directly if it's
within limits of its associated tg (throtl_grp). This behavior
becomes incorrect with hierarchy support as the bio should be
accounted to and throttled by the ancestor throtl_grps too.This patch makes the direct issue path of blk_throtl_bio() to loop
until it reaches the top-level service_queue or gets throttled. If
the former, the bio can be issued directly; otherwise, it gets queued
at the first layer it was above limits.As tg->parent_sq is always the top-level service queue currently, this
patch in itself doesn't make any behavior differences.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
The current blk_throtl_drain() assumes that all active throtl_grps are
queued on throtl_data->service_queue, which won't be true once
hierarchy support is implemented.This patch makes blk_throtl_drain() perform post-order walk of the
blkg hierarchy draining each associated throtl_grp, which guarantees
that all bios will eventually be pushed to the top-level service_queue
in throtl_data.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
Currently, blk_throtl_dispatch_work_fn() is responsible for both
dispatching bio's from throtl_grp's according to their limits and then
issuing the dispatched bios.This patch moves the dispatch part to throtl_pending_timer_fn() so
that the work item is kicked iff there are bio's to issue. This is to
avoid work item execution at each step when hierarchy support is
enabled. bio's will be dispatched towards the top-level service_queue
from the timers at each layer and the work item will only be used to
issue the bio's which reached the top-level service_queue.While fetching bio's to issue from bio_lists[],
blk_throtl_dispatch_work_fn() fetches all READs before WRITEs. While
the original code also dispatched READs first, if multiple throtl_grps
are dispatched on the same run, WRITEs from throtl_grp which is
dispatched first would precede READs from throtl_grps which are
dispatched later. While this is a behavior change, given that the
previous code already prioritized READs and block layer generally
prioritizes and segregates READs from WRITEs, this isn't likely to
make any noticeable differences.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
throtl_select_dispatch() only dispatches throtl_quantum bios on each
invocation. blk_throtl_dispatch_work_fn() in turn depends on
throtl_schedule_next_dispatch() scheduling the next dispatch window
immediately so that undue delays aren't incurred. This effectively
chains multiple dispatch work item executions back-to-back when there
are more than throtl_quantum bios to dispatch on a given tick.There is no reason to finish the current work item just to repeat it
immediately. This patch makes throtl_schedule_next_dispatch() return
%false without doing anything if the current dispatch window is still
open and updates blk_throtl_dispatch_work_fn() repeat dispatching
after cpu_relax() on %false return.This change will help implementing hierarchy support as dispatching
will be done from pending_timer and immediate reschedule of timer
function isn't supported and doesn't make much sense.While this patch changes how dispatch behaves when there are more than
throtl_quantum bios to dispatch on a single tick, the behavior change
is immaterial.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
Currently, throtl_data->dispatch_work is a delayed_work item which
handles both delayed dispatch and issuing bios. The two tasks will be
separated to support proper hierarchy. To prepare for that, this
patch separates out the timer into throtl_service_queue->pending_timer
from throtl_data->dispatch_work and make the latter a work_struct.* As the timer is now per-service_queue, it's initialized and
del_sync'd as its corresponding service_queue is created and
destroyed. The timer, when triggered, simply schedules
throtl_data->dispathc_work for execution.* throtl_schedule_delayed_work() is renamed to
throtl_schedule_pending_timer() and takes @sq and @expires now.* Simiarly, throtl_schedule_next_dispatch() now takes @sq, which
should be the parent_sq of the service_queue which just got a new
bio or updated. As the parent_sq is always the top-level
service_queue now, this doesn't change anything at this point.This patch doesn't introduce any behavior differences.
Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
With proper hierarchy support, a bio can be dispatched multiple times
until it reaches the top-level service_queue and we don't want to
update dispatch stats at each step. They are local stats and will be
kept local. If recursive stats are necessary, they should be
implemented separately and definitely not by updating counters
recursively on each dispatch.This patch moves REQ_THROTTLED setting to throtl_charge_bio() and gate
stats update with it so that dispatch stats are updated only on the
first time the bio is charged to a throtl_grp, which will always be
the throtl_grp the bio was originally queued to.This means that REQ_THROTTLED would be set even for bios which don't
get throttled. As we don't want bios to leave blk-throtl with the
flag set, move REQ_THROTLLED clearing to the end of blk_throtl_bio()
and clear if the bio is being issued directly.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
Now that both throtl_data and throtl_grp embed throtl_service_queue,
we can unify throtl_log() and throtl_log_tg().* sq_to_tg() is added. This returns the throtl_grp a service_queue is
embedded in. If the service_queue is the top-level one embedded in
throtl_data, NULL is returned.* sq_to_td() is added. A service_queue is always associated with a
throtl_data. This function finds the associated td and returns it.* throtl_log() is updated to take throtl_service_queue instead of
throtl_data. If the service_queue is one embedded in throtl_grp, it
prints the same header as throtl_log_tg() did. If it's one embedded
in throtl_data, it behaves the same as before. This renders
throtl_log_tg() unnecessary. Removed.This change is necessary for hierarchy support as we're gonna be using
the same code paths to dispatch bios to intermediate service_queues
embedded in throtl_grps and the top-level service_queue embedded in
throtl_data.This patch doesn't make any behavior changes.
v2: throtl_log() didn't print a space after blkg path. Updated so
that it prints a space after throtl_grp path. Spotted by Vivek.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
To prepare for hierarchy support, this patch adds
throtl_service_queue->service_sq which points to the arent
service_queue. Currently, for all service_queues embedded in
throtl_grps, it points to throtl_data->service_queue. As
throtl_data->service_queue doesn't have a parent its parent_sq is set
to NULL.There are a number of functions which take both throtl_grp *tg and
throtl_service_queue *parent_sq. With this patch, the parent
service_queue can be determined from @tg and the @parent_sq arguments
are removed.This patch doesn't make any behavior differences.
Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
When blk_throtl_bio() wants to queue a bio to a tg (throtl_grp), it
avoids invoking tg_update_disptime() and
throtl_schedule_next_dispatch() if the tg already has bios queued in
that direction. As a new bio is appeneded after the existing ones, it
can't change the tg's next dispatch time or the parent's dispatch
schedule.This optimization is currently open coded in blk_throtl_bio().
Whether the target biolist was occupied was recorded in a local
variable and later used to skip disptime update. This patch moves
generalizes it so that throtl_add_bio_tg() sets a new flag
THROTL_TG_WAS_EMPTY if the biolist was empty before the new bio was
added. tg_update_disptime() clears the flag automatically.
blk_throtl_bio() is updated to simply test the flag before updating
disptime.This patch doesn't make any functional differences now but will enable
using the same optimization for recursive dispatch.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
throtl_service_queues will eventually form a tree which is anchored at
throtl_data->service_queue and queue bios will climb the tree to the
top service_queue to be executed.This patch makes the dispatch paths in blk_throtl_dispatch_work_fn()
and blk_throtl_drain() to dispatch bios to
throtl_data->service_queue.bio_lists[] instead of the on-stack
bio_lists. This will keep the final dispatch to the top level
service_queue share the same mechanism as dispatches through the rest
of the hierarchy.As bio's should be issued in a sleepable context,
blk_throtl_dispatch_work_fn() transfers all dispatched bio's from the
service_queue bio_lists[] into an onstack one before dropping
queue_lock and issuing the bio's.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
throtl_service_queues will eventually form a tree which is anchored at
throtl_data->service_queue and queue bios will climb the tree to the
top service_queue to be executed.This patch moves bio_lists[] and nr_queued[] from throtl_grp to its
service_queue to prepare for that. As currently only the
throtl_data->service_queue is in use, this patch just ends up moving
throtl_grp->bio_lists[] and ->nr_queued[] to
throtl_grp->service_queue.bio_lists[] and ->nr_queued[] without making
any functional differences.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
Currently, there's single service_queue per queue -
throtl_data->service_queue. All active throtl_grp's are queued on the
queue and dispatched according to their limits. To support hierarchy,
this will be expanded such that active throtl_grp's form a tree
anchored at throtl_data->service_queue and chained through each
intermediate throtl_grp's service_queue.This patch adds throtl_grp->service_queue to prepare for hierarchy
support. The initialization function - throtl_service_queue_init() -
is added and replaces the macro initializer. The newly added
tg->service_queue isn't used yet. Following patches will do.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
throtl_service_queue will be the building block of hierarchy support
and will form a tree. This patch updates its usages as arguments to
reduce confusion.* When a service queue is used as the parent role - the host of the
rbtree - use @parent_sq instead of @sq.* For functions taking both @tg and @parent_sq, reorder them so that
the order is (@tg, @parent_sq) not the other way around. This makes
the code follow the usual convention of specifying the primary
target of the operation as the first argument.This patch doesn't make any functional differences.
Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
throtl_service_queue will be used as the basic block to implement
hierarchy support. Pass around throtl_service_queue *sq instead of
throtl_data *td in the following functions which will be used across
multiple levels of hierarchy.* [__]throtl_enqueue/dequeue_tg()
* throtl_add_bio_tg()
* tg_update_disptime()
* throtl_select_dispatch()
Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
Add throtl_grp->td so that the td (throtl_data) a given tg
(throtl_grp) belongs to can be determined, and remove @td argument
from functions which take both @td and @tg as the former now can be
determined from the latter.This generally simplifies the code and removes a number of cases where
@td is passed as an argument without being actually used. This will
also help hierarchy support implementation.While at it, in multi-line conditions, move the logical operators
leading broken lines to the end of the previous line.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
blk-throttle is still using function-defining macros to define flag
handling functions, which went out style at least a decade ago.Just define the flag as bitmask and use direct bit operations.
This patch doesn't make any functional changes.
Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
throtl_rb_root will be expanded to cover more roles for hierarchy
support. Rename it to throtl_service_queue and make its fields more
descriptive.* rb -> pending_tree
* left -> first_pending
* count -> nr_pending
* min_disptime -> first_pending_disptimeThis patch is purely cosmetic.
Signed-off-by: Tejun Heo
-
throtl_nr_queued() is used in several places to avoid performing
certain operations when the throtl_data is empty. This usually is
useless as those paths usually aren't traveled if there's no bio
queued.* throtl_schedule_delayed_work() skips scheduling dispatch work item
if @td doesn't have any bios queued; however, the only case it can
be called when @td is empty is from tg_set_conf() which isn't
something we should be optimizing for.* throtl_schedule_next_dispatch() takes a quick exit if @td is empty;
however, right after that it triggers BUG if the service tree is
empty. The two conditions are equivalent and it can just test
@st->count for the quick exit.* blk_throtl_dispatch_work_fn() skips dispatch if @td is empty. This
work function isn't usually invoked when @td is empty. The only
possibility is from tg_set_conf() and when it happens the normal
dispatching path can handle empty @td fine. No need to add special
skip path.This patch removes the above three unnecessary optimizations, which
leave throtl_log() call in blk_throtl_dispatch_work_fn() the only user
of throtl_nr_queued(). Remove throtl_nr_queued() and open code it in
throtl_log(). I don't think we need td->nr_queued[] at all. Maybe we
can remove it later.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
Move throtl_schedule_delayed_work() above its first user so that the
forward declaration can be removed.This patch is pure relocaiton.
Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
blk-throttle is about to go through major restructuring to support
hierarchy. Do cosmetic updates in preparation.* s/throtl_data->throtl_work/throtl_data->dispatch_work/
* s/blk_throtl_work()/blk_throtl_dispatch_work_fn()/
* Collapse throtl_dispatch() into blk_throtl_dispatch_work_fn()
This patch is purely cosmetic.
Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
When bps or iops configuration changes, blk-throttle records the new
configuration and sets a flag indicating that the config has changed.
The flag is checked in the bio dispatch path and applied. This
deferred config application was necessary due to limitations in blkcg
framework, which haven't existed for quite a while now.This patch removes the deferred config application mechanism and
applies new configurations directly from tg_set_conf(), which is
simpler.v2: Dropped unnecessary throtl_schedule_delayed_work() call from
tg_set_conf() as suggested by Vivek Goyal.Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal -
throtl_select_dispatch() calls throtl_enqueue_tg() right after
tg_update_disptime(), which always calls the function anyway. The
call is, while harmless, unnecessary. Remove it.This patch doesn't introduce any behavior difference.
Signed-off-by: Tejun Heo
Acked-by: Vivek Goyal
06 Dec, 2012
1 commit
-
QUEUE_FLAG_DEAD is used to indicate that queuing new requests must
stop. After this flag has been set queue draining starts. However,
during the queue draining phase it is still safe to invoke the
queue's request_fn, so QUEUE_FLAG_DYING is a better name for this
flag.This patch has been generated by running the following command
over the kernel source tree:git grep -lEw 'blk_queue_dead|QUEUE_FLAG_DEAD' |
xargs sed -i.tmp -e 's/blk_queue_dead/blk_queue_dying/g' \
-e 's/QUEUE_FLAG_DEAD/QUEUE_FLAG_DYING/g'; \
sed -i.tmp -e "s/QUEUE_FLAG_DYING$(printf \\t)*5/QUEUE_FLAG_DYING$(printf \\t)5/g" \
include/linux/blkdev.h; \
sed -i.tmp -e 's/ DEAD/ DYING/g' -e 's/dead queue/a dying queue/' \
-e 's/Dead queue/A dying queue/' block/blk-core.cSigned-off-by: Bart Van Assche
Acked-by: Tejun Heo
Cc: James Bottomley
Cc: Mike Christie
Cc: Jens Axboe
Cc: Chanho Min
Signed-off-by: Jens Axboe
22 Aug, 2012
1 commit
-
Now that mod_delayed_work() is safe to call from IRQ handlers,
__cancel_delayed_work() followed by queue_delayed_work() can be
replaced with mod_delayed_work().Most conversions are straight-forward except for the following.
* net/core/link_watch.c: linkwatch_schedule_work() was doing a quite
elaborate dancing around its delayed_work. Collapse it such that
linkwatch_work is queued for immediate execution if LW_URGENT and
existing timer is kept otherwise.Signed-off-by: Tejun Heo
Cc: "David S. Miller"
Cc: Tomi Valkeinen
21 Aug, 2012
1 commit
-
system_nrt[_freezable]_wq are now spurious. Mark them deprecated and
convert all users to system[_freezable]_wq.If you're cc'd and wondering what's going on: Now all workqueues are
non-reentrant, so there's no reason to use system_nrt[_freezable]_wq.
Please use system[_freezable]_wq instead.This patch doesn't make any functional difference.
Signed-off-by: Tejun Heo
Acked-By: Lai JiangshanCc: Jens Axboe
Cc: David Airlie
Cc: Jiri Kosina
Cc: "David S. Miller"
Cc: Rusty Russell
Cc: "Paul E. McKenney"
Cc: David Howells