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* cgroup: mark subsystems with broken hierarchy support and whine if cgroups ↵Tejun Heo2012-09-141-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | are nested for them Currently, cgroup hierarchy support is a mess. cpu related subsystems behave correctly - configuration, accounting and control on a parent properly cover its children. blkio and freezer completely ignore hierarchy and treat all cgroups as if they're directly under the root cgroup. Others show yet different behaviors. These differing interpretations of cgroup hierarchy make using cgroup confusing and it impossible to co-mount controllers into the same hierarchy and obtain sane behavior. Eventually, we want full hierarchy support from all subsystems and probably a unified hierarchy. Users using separate hierarchies expecting completely different behaviors depending on the mounted subsystem is deterimental to making any progress on this front. This patch adds cgroup_subsys.broken_hierarchy and sets it to %true for controllers which are lacking in hierarchy support. The goal of this patch is two-fold. * Move users away from using hierarchy on currently non-hierarchical subsystems, so that implementing proper hierarchy support on those doesn't surprise them. * Keep track of which controllers are broken how and nudge the subsystems to implement proper hierarchy support. For now, start with a single warning message. We can whine louder later on. v2: Fixed a typo spotted by Michal. Warning message updated. v3: Updated memcg part so that it doesn't generate warning in the cases where .use_hierarchy=false doesn't make the behavior different from root.use_hierarchy=true. Fixed a typo spotted by Glauber. v4: Check ->broken_hierarchy after cgroup creation is complete so that ->create() can affect the result per Michal. Dropped unnecessary memcg root handling per Michal. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul Turner <pjt@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Thomas Graf <tgraf@suug.ch> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
* blkcg: implement per-blkg request allocationTejun Heo2012-06-261-4/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, request_queue has one request_list to allocate requests from regardless of blkcg of the IO being issued. When the unified request pool is used up, cfq proportional IO limits become meaningless - whoever grabs the next request being freed wins the race regardless of the configured weights. This can be easily demonstrated by creating a blkio cgroup w/ very low weight, put a program which can issue a lot of random direct IOs there and running a sequential IO from a different cgroup. As soon as the request pool is used up, the sequential IO bandwidth crashes. This patch implements per-blkg request_list. Each blkg has its own request_list and any IO allocates its request from the matching blkg making blkcgs completely isolated in terms of request allocation. * Root blkcg uses the request_list embedded in each request_queue, which was renamed to @q->root_rl from @q->rq. While making blkcg rl handling a bit harier, this enables avoiding most overhead for root blkcg. * Queue fullness is properly per request_list but bdi isn't blkcg aware yet, so congestion state currently just follows the root blkcg. As writeback isn't aware of blkcg yet, this works okay for async congestion but readahead may get the wrong signals. It's better than blkcg completely collapsing with shared request_list but needs to be improved with future changes. * After this change, each block cgroup gets a full request pool making resource consumption of each cgroup higher. This makes allowing non-root users to create cgroups less desirable; however, note that allowing non-root users to directly manage cgroups is already severely broken regardless of this patch - each block cgroup consumes kernel memory and skews IO weight (IO weights are not hierarchical). v2: queue-sysfs.txt updated and patch description udpated as suggested by Vivek. v3: blk_get_rl() wasn't checking error return from blkg_lookup_create() and may cause oops on lookup failure. Fix it by falling back to root_rl on blkg lookup failures. This problem was spotted by Rakesh Iyer <rni@google.com>. v4: Updated to accomodate 458f27a982 "block: Avoid missed wakeup in request waitqueue". blk_drain_queue() now wakes up waiters on all blkg->rl on the target queue. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: inline bio_blkcg() and friendsTejun Heo2012-06-251-21/+0
| | | | | | | | | | | | Make bio_blkcg() and friends inline. They all are very simple and used only in few places. This patch is to prepare for further updates to request allocation path. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: make root blkcg allocation use %GFP_KERNELTejun Heo2012-06-251-16/+43
| | | | | | | | | | | | | | | | | | Currently, blkcg_activate_policy() depends on %GFP_ATOMIC allocation from __blkg_lookup_create() for root blkcg creation. This could make policy fail unnecessarily. Make blkg_alloc() take @gfp_mask, __blkg_lookup_create() take an optional @new_blkg for preallocated blkg, and blkcg_activate_policy() preload radix tree and preallocate blkg with %GFP_KERNEL before trying to create the root blkg. v2: __blkg_lookup_create() was returning %NULL on blkg alloc failure instead of ERR_PTR() value. Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: __blkg_lookup_create() doesn't need radix preloadTejun Heo2012-06-251-9/+1
| | | | | | | | | | | | | | | There's no point in calling radix_tree_preload() if preloading doesn't use more permissible GFP mask. Drop preloading from __blkg_lookup_create(). While at it, drop sparse locking annotation which no longer applies. v2: Vivek pointed out the odd preload usage. Instead of updating, just drop it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: drop local variable @q from blkg_destroy()Tejun Heo2012-06-061-2/+1
| | | | | | | | | | | | blkg_destroy() caches @blkg->q in local variable @q. While there are two places which needs @blkg->q, only lockdep_assert_held() used the local variable leading to unused local variable warning if lockdep is configured out. Drop the local variable and just use @blkg->q directly. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Rakesh Iyer <rni@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: fix blkg_alloc() failure pathTejun Heo2012-06-041-5/+1
| | | | | | | | | | | | When policy data allocation fails in the middle, blkg_alloc() invokes blkg_free() to destroy the half constructed blkg. This ends up calling pd_exit_fn() on policy datas which didn't go through pd_init_fn(). Fix it by making blkg_alloc() call pd_init_fn() immediately after each policy data allocation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: use radix tree to index blkgs from blkcgTejun Heo2012-04-201-8/+44
| | | | | | | | | | | | | | | | | | | | blkg lookup is currently performed by traversing linked list anchored at blkcg->blkg_list. This is very unscalable and with blk-throttle enabled and enough request queues on the system, this can get very ugly quickly (blk-throttle performs look up on every bio submission). This patch makes blkcg use radix tree to index blkgs combined with simple last-looked-up hint. This is mostly identical to how icqs are indexed from ioc. Note that because __blkg_lookup() may be invoked without holding queue lock, hint is only updated from __blkg_lookup_create(). Due to cfq's cfqq caching, this makes hint updates overly lazy. This will be improved with scheduled blkcg aware request allocation. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: fix blkcg->css ref leak in __blkg_lookup_create()Tejun Heo2012-04-201-10/+9
| | | | | | | | | __blkg_lookup_create() leaked blkcg->css ref if blkg allocation failed. Fix it. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: collapse blkcg_policy_ops into blkcg_policyTejun Heo2012-04-201-8/+8
| | | | | | | | | | | There's no reason to keep blkcg_policy_ops separate. Collapse it into blkcg_policy. This patch doesn't introduce any functional change. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: embed struct blkg_policy_data in policy specific dataTejun Heo2012-04-201-26/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently blkg_policy_data carries policy specific data as char flex array instead of being embedded in policy specific data. This was forced by oddities around blkg allocation which are all gone now. This patch makes blkg_policy_data embedded in policy specific data - throtl_grp and cfq_group so that it's more conventional and consistent with how io_cq is handled. * blkcg_policy->pdata_size is renamed to ->pd_size. * Functions which used to take void *pdata now takes struct blkg_policy_data *pd. * blkg_to_pdata/pdata_to_blkg() updated to blkg_to_pd/pd_to_blkg(). * Dummy struct blkg_policy_data definition added. Dummy pdata_to_blkg() definition was unused and inconsistent with the non-dummy version - correct dummy pd_to_blkg() added. * throtl and cfq updated accordingly. * As dummy blkg_to_pd/pd_to_blkg() are provided, blkg_to_cfqg/cfqg_to_blkg() don't need to be ifdef'd. Moved outside ifdef block. This patch doesn't introduce any functional change. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: mass rename of blkcg APITejun Heo2012-04-201-103/+99
| | | | | | | | | | | | | | | | | | | | | | | | During the recent blkcg cleanup, most of blkcg API has changed to such extent that mass renaming wouldn't cause any noticeable pain. Take the chance and cleanup the naming. * Rename blkio_cgroup to blkcg. * Drop blkio / blkiocg prefixes and consistently use blkcg. * Rename blkio_group to blkcg_gq, which is consistent with io_cq but keep the blkg prefix / variable name. * Rename policy method type and field names to signify they're dealing with policy data. * Rename blkio_policy_type to blkcg_policy. This patch doesn't cause any functional change. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: remove blkio_group->path[]Tejun Heo2012-04-201-1/+0
| | | | | | | | | | blkio_group->path[] stores the path of the associated cgroup and is used only for debug messages. Just format the path from blkg->cgroup when printing debug messages. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: shoot down blkgs if all policies are deactivatedTejun Heo2012-04-201-3/+8
| | | | | | | | | | | | | There's no reason to keep blkgs around if no policy is activated for the queue. This patch moves queue locking out of blkg_destroy_all() and call it from blkg_deactivate_policy() on deactivation of the last policy on the queue. This change was suggested by Vivek. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: drop stuff unused after per-queue policy activation updateTejun Heo2012-04-201-41/+20
| | | | | | | | | | | | | | | | * All_q_list is unused. Drop all_q_{mutex|list}. * @for_root of blkg_lookup_create() is always %false when called from outside blk-cgroup.c proper. Factor out __blkg_lookup_create() so that it doesn't check whether @q is bypassing and use the underscored version for the @for_root callsite. * blkg_destroy_all() is used only from blkcg proper and @destroy_root is always %true. Make it static and drop @destroy_root. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: implement per-queue policy activationTejun Heo2012-04-201-74/+154
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All blkcg policies were assumed to be enabled on all request_queues. Due to various implementation obstacles, during the recent blkcg core updates, this was temporarily implemented as shooting down all !root blkgs on elevator switch and policy [de]registration combined with half-broken in-place root blkg updates. In addition to being buggy and racy, this meant losing all blkcg configurations across those events. Now that blkcg is cleaned up enough, this patch replaces the temporary implementation with proper per-queue policy activation. Each blkcg policy should call the new blkcg_[de]activate_policy() to enable and disable the policy on a specific queue. blkcg_activate_policy() allocates and installs policy data for the policy for all existing blkgs. blkcg_deactivate_policy() does the reverse. If a policy is not enabled for a given queue, blkg printing / config functions skip the respective blkg for the queue. blkcg_activate_policy() also takes care of root blkg creation, and cfq_init_queue() and blk_throtl_init() are updated accordingly. This replaces blkcg_bypass_{start|end}() and update_root_blkg_pd() unnecessary. Dropped. v2: cfq_init_queue() was returning uninitialized @ret on root_group alloc failure if !CONFIG_CFQ_GROUP_IOSCHED. Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: make sure blkg_lookup() returns %NULL if @q is bypassingTejun Heo2012-04-201-17/+33
| | | | | | | | | | | | | | | | | | | | | | Currently, blkg_lookup() doesn't check @q bypass state. This patch updates blk_queue_bypass_start() to do synchronize_rcu() before returning and updates blkg_lookup() to check blk_queue_bypass() and return %NULL if bypassing. This ensures blkg_lookup() returns %NULL if @q is bypassing. This is to guarantee that nobody is accessing policy data while @q is bypassing, which is necessary to allow replacing blkio_cgroup->pd[] in place on policy [de]activation. v2: Added more comments explaining bypass guarantees as suggested by Vivek. v3: Added more comments explaining why there's no synchronize_rcu() in blk_cleanup_queue() as suggested by Vivek. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: make blkg_conf_prep() take @pol and return with queue lock heldTejun Heo2012-04-201-7/+10
| | | | | | | | | | | | | Add @pol to blkg_conf_prep() and let it return with queue lock held (to be released by blkg_conf_finish()). Note that @pol isn't used yet. This is to prepare for per-queue policy activation and doesn't cause any visible difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: remove static policy ID enumsTejun Heo2012-04-201-15/+44
| | | | | | | | | | | | | | Remove BLKIO_POLICY_* enums and let blkio_policy_register() allocate @pol->plid dynamically on registration. The maximum number of blkcg policies which can be registered at the same time is defined by BLKCG_MAX_POLS constant added to include/linux/blkdev.h. Note that blkio_policy_register() now may fail. Policy init functions updated accordingly and unnecessary ifdefs removed from cfq_init(). Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: use @pol instead of @plid in update_root_blkg_pd() and ↵Tejun Heo2012-04-201-10/+11
| | | | | | | | | | | | | | blkcg_print_blkgs() The two functions were taking "enum blkio_policy_id plid". Make them take "const struct blkio_policy_type *pol" instead. This is to prepare for per-queue policy activation and doesn't cause any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: kill blkio_list and replace blkio_list_lock with a mutexTejun Heo2012-04-201-15/+17
| | | | | | | | | | | | | | With blkio_policy[], blkio_list is redundant and hinders with per-queue policy activation. Remove it. Also, replace blkio_list_lock with a mutex blkcg_pol_mutex and let it protect the whole [un]registration. This is to prepare for per-queue policy activation and doesn't cause any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: drop BLKCG_STAT_{PRIV|POL|OFF} macrosTejun Heo2012-04-011-28/+20
| | | | | | | | | | | | | | Now that all stat handling code lives in policy implementations, there's no need to encode policy ID in cft->private. * Export blkcg_prfill_[rw]stat() from blkcg, remove blkcg_print_[rw]stat(), and implement cfqg_print_[rw]stat() which use hard-code BLKIO_POLICY_PROP. * Use cft->private for offset of the target field directly and drop BLKCG_STAT_{PRIV|POL|OFF}(). Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: pass around pd->pdata instead of pd itself in prfill functionsTejun Heo2012-04-011-18/+15
| | | | | | | | | Now that all conf and stat fields are moved into policy specific blkio_policy_data->pdata areas, there's no reason to use blkio_policy_data itself in prfill functions. Pass around @pd->pdata instead of @pd. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: move blkio_group_conf->weight to cfqTejun Heo2012-04-011-2/+2
| | | | | | | | | | | | | | blkio_group_conf->weight is owned by cfq and has no reason to be defined in blkcg core. Replace it with cfq_group->dev_weight and let conf setting functions directly set it. If dev_weight is zero, the cfqg doesn't have device specific weight configured. Also, rename BLKIO_WEIGHT_* constants to CFQ_WEIGHT_* and rename blkio_cgroup->weight to blkio_cgroup->cfq_weight. We eventually want per-policy storage in blkio_cgroup but just mark the ownership of the field for now. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: move blkio_group_stats_cpu and friends to blk-throttle.cTejun Heo2012-04-011-97/+1
| | | | | | | | | | | | | | | | | | | | | | | | | blkio_group_stats_cpu is used only by blk-throtl and has no reason to be defined in blkcg core. * Move blkio_group_stats_cpu to blk-throttle.c and rename it to tg_stats_cpu. * blkg_policy_data->stats_cpu is replaced with throtl_grp->stats_cpu. prfill functions updated accordingly. * All related macros / functions are renamed so that they have tg_ prefix and the unnecessary @pol arguments are dropped. * Per-cpu stats allocation code is also moved from blk-cgroup.c to blk-throttle.c and gets simplified to only deal with BLKIO_POLICY_THROTL. percpu stat free is performed by the exit method throtl_exit_blkio_group(). * throtl_reset_group_stats() implemented for blkio_reset_group_stats_fn method so that tg->stats_cpu can be reset. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: move blkio_group_stats to cfq-iosched.cTejun Heo2012-04-011-21/+2
| | | | | | | | | | | | | | | | | | | | | | | | | blkio_group_stats contains only fields used by cfq and has no reason to be defined in blkcg core. * Move blkio_group_stats to cfq-iosched.c and rename it to cfqg_stats. * blkg_policy_data->stats is replaced with cfq_group->stats. blkg_prfill_[rw]stat() are updated to use offset against pd->pdata instead. * All related macros / functions are renamed so that they have cfqg_ prefix and the unnecessary @pol arguments are dropped. * All stat functions now take cfq_group * instead of blkio_group *. * lockdep assertion on queue lock dropped. Elevator runs under queue lock by default. There isn't much to be gained by adding lockdep assertions at stat function level. * cfqg_stats_reset() implemented for blkio_reset_group_stats_fn method so that cfqg->stats can be reset. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: add blkio_policy_ops operations for exit and stat resetTejun Heo2012-04-011-4/+12
| | | | | | | | Add blkio_policy_ops->blkio_exit_group_fn() and ->blkio_reset_group_stats_fn(). These will be used to further modularize blkcg policy implementation. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: cfq doesn't need per-cpu dispatch statsTejun Heo2012-04-011-61/+2
| | | | | | | | | | | | | | | | | | blkio_group_stats_cpu is used to count dispatch stats using per-cpu counters. This is used by both blk-throtl and cfq-iosched but the sharing is rather silly. * cfq-iosched doesn't need per-cpu dispatch stats. cfq always updates those stats while holding queue_lock. * blk-throtl needs per-cpu dispatch stats but only service_bytes and serviced. It doesn't make use of sectors. This patch makes cfq add and use global stats for service_bytes, serviced and sectors, removes per-cpu sectors counter and moves per-cpu stat printing code to blk-throttle.c. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: move statistics update code to policiesTejun Heo2012-04-011-245/+0
| | | | | | | | | | | | | | | As with conf/stats file handling code, there's no reason for stat update code to live in blkcg core with policies calling into update them. The current organization is both inflexible and complex. This patch moves stat update code to specific policies. All blkiocg_update_*_stats() functions which deal with BLKIO_POLICY_PROP stats are collapsed into their cfq_blkiocg_update_*_stats() counterparts. blkiocg_update_dispatch_stats() is used by both policies and duplicated as throtl_update_dispatch_stats() and cfq_blkiocg_update_dispatch_stats(). This will be cleaned up later. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: move conf/stat file handling code to policiesTejun Heo2012-04-011-373/+0
| | | | | | | | | | | | | | | | | | | | | | | blkcg conf/stat handling is convoluted in that details which belong to specific policy implementations are all out in blkcg core and then policies hook into core layer to access and manipulate confs and stats. This sadly achieves both inflexibility (confs/stats can't be modified without messing with blkcg core) and complexity (all the call-ins and call-backs). The previous patches restructured conf and stat handling code such that they can be separated out. This patch relocates the file handling part. All conf/stat file handling code which belongs to BLKIO_POLICY_PROP is moved to cfq-iosched.c and all BKLIO_POLICY_THROTL code to blk-throtl.c. The move is verbatim except for blkio_update_group_{weight|bps|iops}() callbacks which relays conf changes to policies. The configuration settings are handled in policies themselves so the relaying isn't necessary. Conf setting functions are modified to directly call per-policy update functions and the relaying mechanism is dropped. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: implement blkio_policy_type->cftypesTejun Heo2012-04-011-0/+6
| | | | | | | Add blkiop->cftypes which is added and removed together with the policy. This will be used to move conf/stat handling to the policies. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: export conf/stat helpers to prepare for reorganizationTejun Heo2012-04-011-27/+25
| | | | | | | | conf/stat handling is about to be moved to policy implementation from blkcg core. Export conf/stat helpers from blkcg core so that blk-throttle and cfq-iosched can use them. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: simplify blkg_conf_prep()Tejun Heo2012-04-011-54/+10
| | | | | | | | blkg_conf_prep() implements "MAJ:MIN VAL" parsing manually, which is unnecessary. Just use sscanf("%u:%u %llu"). This might not reject some malformed input (extra input at the end) but we don't care. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: restructure blkio_group configruation settingTejun Heo2012-04-011-127/+147
| | | | | | | | | | | | | | As part of userland interface restructuring, this patch updates per-blkio_group configuration setting. Instead of funneling everything through a master function which has hard-coded cases for each config file it may handle, the common part is factored into blkg_conf_prep() and blkg_conf_finish() and different configuration setters are implemented using the helpers. While this doesn't result in immediate LOC reduction, this enables further cleanups and more modular implementation. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: restructure configuration printingTejun Heo2012-04-011-102/+54
| | | | | | | | | | | | | | | | | | | | | | | | | Similarly to the previous stat restructuring, this patch restructures conf printing code such that, * Conf printing uses the same helpers as stat. * Printing function doesn't require hardcoded switching on the config being printed. Note that this isn't complete yet for throttle confs. The next patch will convert setting for these confs and will complete the transition. * Printing uses read_seq_string callback (other methods will be phased out). Note that blkio_group_conf.iops[2] is changed to u64 so that they can be manipulated with the same functions. This is transitional and will go away later. After this patch, per-device configurations - weight, bps and iops - use __blkg_prfill_u64() for printing which uses white space as delimiter instead of tab. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: drop blkiocg_file_write_u64()Tejun Heo2012-04-011-28/+7
| | | | | | | | blkiocg_file_write_u64() has single switch case. Drop blkiocg_file_write_u64(), rename blkio_weight_write() to blkcg_set_weight() and use it directly for .write_u64 callback. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: restructure statistics printingTejun Heo2012-04-011-318/+239
| | | | | | | | | | | | | | | | | | | | | | | blkcg stats handling is a mess. None of the stats has much to do with blkcg core but they are all implemented in blkcg core. Code sharing is achieved by mixing common code with hard-coded cases for each stat counter. This patch restructures statistics printing such that * Common logic exists as helper functions and specific print functions use the helpers to implement specific cases. * Printing functions serving multiple counters don't require hardcoded switching on specific counters. * Printing uses read_seq_string callback (other methods will be phased out). This change enables further cleanups and relocating stats code to the policy implementation it belongs to. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: introduce blkg_stat and blkg_rwstatTejun Heo2012-04-011-162/+127
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | blkcg uses u64_stats_sync to avoid reading wrong u64 statistic values on 32bit archs and some stat counters have subtypes to distinguish read/writes and sync/async IOs. The stat code paths are confusing and involve a lot of going back and forth between blkcg core and specific policy implementations, and synchronization and subtype handling are open coded in blkcg core. This patch introduces struct blkg_stat and blkg_rwstat which, with accompanying operations, encapsulate stat updating and accessing with proper synchronization. blkg_stat is simple u64 counter with 64bit read-access protection. blkg_rwstat is the one with rw and [a]sync subcounters and takes @rw flags to distinguish IO subtypes (%REQ_WRITE and %REQ_SYNC) and replaces stat_sub_type indexed arrays. All counters in blkio_group_stats and blkio_group_stats_cpu are replaced with either blkg_stat or blkg_rwstat along with all users. This does add one u64_stats_sync per counter and increase stats_sync operations but they're empty/noops on 64bit archs and blkcg doesn't have too many counters, especially with DEBUG_BLK_CGROUP off. While the currently resulting code isn't necessarily simpler at the moment, this will enable further clean up of blkcg stats code. - BLKIO_STAT_{READ|WRITE|SYNC|ASYNC|TOTAL} renamed to BLKG_RWSTAT_{READ|WRITE|SYNC|ASYNC|TOTAL}. - blkg_stat_add() replaces blkio_add_stat() and blkio_check_and_dec_stat(). Note that BUG_ON() on underflow in the latter function no longer exists. It's *way* better to have underflowed stat counters than oopsing. - blkio_group_stats->dequeue is now a proper u64 stat counter instead of ulong. - reset_stats() updated to clear each stat counters individually and BLKG_STATS_DEBUG_CLEAR_{START|SIZE} are removed. - Some functions reconstruct rw flags from direction and sync booleans. This will be removed by future patches. Signed-off-by: Tejun Heo <tj@kernel.org>
* blkcg: remove unused @pol and @plid parametersTejun Heo2012-04-011-2/+1
| | | | | | | @pol to blkg_to_pdata() and @plid to blkg_lookup_create() are no longer necessary. Drop them. Signed-off-by: Tejun Heo <tj@kernel.org>
* Merge branch 'for-3.5' of ../cgroup into block/for-3.5/core-mergedTejun Heo2012-04-011-34/+17
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup/for-3.5 contains the following changes which blk-cgroup needs to proceed with the on-going cleanup. * Dynamic addition and removal of cftypes to make config/stat file handling modular for policies. * cgroup removal update to not wait for css references to drain to fix blkcg removal hang caused by cfq caching cfqgs. Pull in cgroup/for-3.5 into block/for-3.5/core. This causes the following conflicts in block/blk-cgroup.c. * 761b3ef50e "cgroup: remove cgroup_subsys argument from callbacks" conflicts with blkiocg_pre_destroy() addition and blkiocg_attach() removal. Resolved by removing @subsys from all subsys methods. * 676f7c8f84 "cgroup: relocate cftype and cgroup_subsys definitions in controllers" conflicts with ->pre_destroy() and ->attach() updates and removal of modular config. Resolved by dropping forward declarations of the methods and applying updates to the relocated blkio_subsys. * 4baf6e3325 "cgroup: convert all non-memcg controllers to the new cftype interface" builds upon the previous item. Resolved by adding ->base_cftypes to the relocated blkio_subsys. Signed-off-by: Tejun Heo <tj@kernel.org>
| * cgroup: convert all non-memcg controllers to the new cftype interfaceTejun Heo2012-04-011-7/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert debug, freezer, cpuset, cpu_cgroup, cpuacct, net_prio, blkio, net_cls and device controllers to use the new cftype based interface. Termination entry is added to cftype arrays and populate callbacks are replaced with cgroup_subsys->base_cftypes initializations. This is functionally identical transformation. There shouldn't be any visible behavior change. memcg is rather special and will be converted separately. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <paul@paulmenage.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Vivek Goyal <vgoyal@redhat.com>
| * cgroup: relocate cftype and cgroup_subsys definitions in controllersTejun Heo2012-04-011-22/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | blk-cgroup, netprio_cgroup, cls_cgroup and tcp_memcontrol unnecessarily define cftype array and cgroup_subsys structures at the top of the file, which is unconventional and necessiates forward declaration of methods. This patch relocates those below the definitions of the methods and removes the forward declarations. Note that forward declaration of tcp_files[] is added in tcp_memcontrol.c for tcp_init_cgroup(). This will be removed soon by another patch. This patch doesn't introduce any functional change. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
| * Merge branch 'for-3.4' of ↵Linus Torvalds2012-03-201-14/+8
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup changes from Tejun Heo: "Out of the 8 commits, one fixes a long-standing locking issue around tasklist walking and others are cleanups." * 'for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: Walk task list under tasklist_lock in cgroup_enable_task_cg_list cgroup: Remove wrong comment on cgroup_enable_task_cg_list() cgroup: remove cgroup_subsys argument from callbacks cgroup: remove extra calls to find_existing_css_set cgroup: replace tasklist_lock with rcu_read_lock cgroup: simplify double-check locking in cgroup_attach_proc cgroup: move struct cgroup_pidlist out from the header file cgroup: remove cgroup_attach_task_current_cg()
| | * cgroup: remove cgroup_subsys argument from callbacksLi Zefan2012-02-021-14/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The argument is not used at all, and it's not necessary, because a specific callback handler of course knows which subsys it belongs to. Now only ->pupulate() takes this argument, because the handlers of this callback always call cgroup_add_file()/cgroup_add_files(). So we reduce a few lines of code, though the shrinking of object size is minimal. 16 files changed, 113 insertions(+), 162 deletions(-) text data bss dec hex filename 5486240 656987 7039960 13183187 c928d3 vmlinux.o.orig 5486170 656987 7039960 13183117 c9288d vmlinux.o Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | | blkcg: change a spin_lock() to spin_lock_irq()Dan Carpenter2012-03-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Smatch complains that we re-enable IRQs twice. It looks like we forgot to disable them here on the spin_trylock() failure path. This was added in 9f13ef678e "blkcg: use double locking instead of RCU for blkg synchronization". Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>` Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | | block: remove ioc_*_changed()Tejun Heo2012-03-201-19/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After the previous patch to cfq, there's no ioc_get_changed() user left. This patch yanks out ioc_{ioprio|cgroup|get}_changed() and all related stuff. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | | blkcg: add blkcg->idTejun Heo2012-03-201-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add 64bit unique id to blkcg. This will be used by policies which want blkcg identity test to tell whether the associated blkcg has changed. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | | blkcg: remove blkio_group->stats_lockTejun Heo2012-03-201-107/+102
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With recent plug merge updates, all non-percpu stat updates happen under queue_lock making stats_lock unnecessary to synchronize stat updates. The only synchronization necessary is stat reading, which can be done using u64_stats_sync instead. This patch removes blkio_group->stats_lock and adds blkio_group_stats->syncp for reader synchronization. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | | blkcg: restructure blkio_get_stat()Tejun Heo2012-03-201-49/+51
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Restructure blkio_get_stat() to prepare for removal of stats_lock. * Define BLKIO_STAT_ARR_NR explicitly to denote which stats have subtypes instead of using BLKIO_STAT_QUEUED. * Separate out stat acquisition and printing. After this, there are only two users of blkio_fill_stat(). Just open code it. * The code was mixing MAX_KEY_LEN and MAX_KEY_LEN - 1. There's no need to subtract one. Use MAX_KEY_LEN consistently. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | | blkcg: simplify stat resetTejun Heo2012-03-201-55/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | blkiocg_reset_stats() implements stat reset for blkio.reset_stats cgroupfs file. This feature is very unconventional and something which shouldn't have been merged. It's only useful when there's only one user or tool looking at the stats. As soon as multiple users and/or tools are involved, it becomes useless as resetting disrupts other usages. There are very good reasons why all other stats expect readers to read values at the start and end of a period and subtract to determine delta over the period. The implementation is rather complex - some fields shouldn't be cleared and it saves some fields, resets whole and restores for some reason. Reset of percpu stats is also racy. The comment points to 64bit store atomicity for the reason but even without that stores for zero can simply race with other CPUs doing RMW and get clobbered. Simplify reset by * Clear selectively instead of resetting and restoring. * Grouping debug stat fields to be reset and using memset() over them. * Not caring about stats_lock. * Using memset() to reset percpu stats. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-18 11:49:40 +0000