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![Christoph Hellwig](/assets/img/avatar_default.png)
Except for pktdvd, the only places setting congested bits are file systems that allocate their own backing_dev_info structures. And pktdvd is a deprecated driver that isn't useful in stack setup either. So remove the dead congested_fn stacking infrastructure. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Song Liu <song@kernel.org> Acked-by: David Sterba <dsterba@suse.com> [axboe: fixup unused variables in bcache/request.c] Signed-off-by: Jens Axboe <axboe@kernel.dk>
290 lines
8 KiB
C
290 lines
8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_BACKING_DEV_DEFS_H
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#define __LINUX_BACKING_DEV_DEFS_H
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#include <linux/list.h>
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#include <linux/radix-tree.h>
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#include <linux/rbtree.h>
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#include <linux/spinlock.h>
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#include <linux/percpu_counter.h>
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#include <linux/percpu-refcount.h>
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#include <linux/flex_proportions.h>
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#include <linux/timer.h>
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#include <linux/workqueue.h>
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#include <linux/kref.h>
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#include <linux/refcount.h>
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struct page;
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struct device;
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struct dentry;
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/*
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* Bits in bdi_writeback.state
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*/
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enum wb_state {
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WB_registered, /* bdi_register() was done */
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WB_writeback_running, /* Writeback is in progress */
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WB_has_dirty_io, /* Dirty inodes on ->b_{dirty|io|more_io} */
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WB_start_all, /* nr_pages == 0 (all) work pending */
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};
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enum wb_congested_state {
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WB_async_congested, /* The async (write) queue is getting full */
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WB_sync_congested, /* The sync queue is getting full */
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};
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enum wb_stat_item {
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WB_RECLAIMABLE,
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WB_WRITEBACK,
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WB_DIRTIED,
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WB_WRITTEN,
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NR_WB_STAT_ITEMS
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};
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#define WB_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
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/*
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* why some writeback work was initiated
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*/
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enum wb_reason {
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WB_REASON_BACKGROUND,
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WB_REASON_VMSCAN,
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WB_REASON_SYNC,
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WB_REASON_PERIODIC,
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WB_REASON_LAPTOP_TIMER,
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WB_REASON_FS_FREE_SPACE,
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/*
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* There is no bdi forker thread any more and works are done
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* by emergency worker, however, this is TPs userland visible
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* and we'll be exposing exactly the same information,
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* so it has a mismatch name.
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*/
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WB_REASON_FORKER_THREAD,
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WB_REASON_FOREIGN_FLUSH,
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WB_REASON_MAX,
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};
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struct wb_completion {
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atomic_t cnt;
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wait_queue_head_t *waitq;
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};
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#define __WB_COMPLETION_INIT(_waitq) \
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(struct wb_completion){ .cnt = ATOMIC_INIT(1), .waitq = (_waitq) }
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/*
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* If one wants to wait for one or more wb_writeback_works, each work's
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* ->done should be set to a wb_completion defined using the following
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* macro. Once all work items are issued with wb_queue_work(), the caller
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* can wait for the completion of all using wb_wait_for_completion(). Work
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* items which are waited upon aren't freed automatically on completion.
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*/
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#define WB_COMPLETION_INIT(bdi) __WB_COMPLETION_INIT(&(bdi)->wb_waitq)
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#define DEFINE_WB_COMPLETION(cmpl, bdi) \
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struct wb_completion cmpl = WB_COMPLETION_INIT(bdi)
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/*
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* Each wb (bdi_writeback) can perform writeback operations, is measured
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* and throttled, independently. Without cgroup writeback, each bdi
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* (bdi_writeback) is served by its embedded bdi->wb.
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*
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* On the default hierarchy, blkcg implicitly enables memcg. This allows
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* using memcg's page ownership for attributing writeback IOs, and every
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* memcg - blkcg combination can be served by its own wb by assigning a
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* dedicated wb to each memcg, which enables isolation across different
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* cgroups and propagation of IO back pressure down from the IO layer upto
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* the tasks which are generating the dirty pages to be written back.
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*
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* A cgroup wb is indexed on its bdi by the ID of the associated memcg,
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* refcounted with the number of inodes attached to it, and pins the memcg
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* and the corresponding blkcg. As the corresponding blkcg for a memcg may
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* change as blkcg is disabled and enabled higher up in the hierarchy, a wb
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* is tested for blkcg after lookup and removed from index on mismatch so
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* that a new wb for the combination can be created.
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*/
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struct bdi_writeback {
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struct backing_dev_info *bdi; /* our parent bdi */
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unsigned long state; /* Always use atomic bitops on this */
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unsigned long last_old_flush; /* last old data flush */
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struct list_head b_dirty; /* dirty inodes */
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struct list_head b_io; /* parked for writeback */
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struct list_head b_more_io; /* parked for more writeback */
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struct list_head b_dirty_time; /* time stamps are dirty */
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spinlock_t list_lock; /* protects the b_* lists */
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struct percpu_counter stat[NR_WB_STAT_ITEMS];
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unsigned long congested; /* WB_[a]sync_congested flags */
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unsigned long bw_time_stamp; /* last time write bw is updated */
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unsigned long dirtied_stamp;
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unsigned long written_stamp; /* pages written at bw_time_stamp */
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unsigned long write_bandwidth; /* the estimated write bandwidth */
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unsigned long avg_write_bandwidth; /* further smoothed write bw, > 0 */
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/*
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* The base dirty throttle rate, re-calculated on every 200ms.
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* All the bdi tasks' dirty rate will be curbed under it.
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* @dirty_ratelimit tracks the estimated @balanced_dirty_ratelimit
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* in small steps and is much more smooth/stable than the latter.
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*/
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unsigned long dirty_ratelimit;
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unsigned long balanced_dirty_ratelimit;
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struct fprop_local_percpu completions;
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int dirty_exceeded;
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enum wb_reason start_all_reason;
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spinlock_t work_lock; /* protects work_list & dwork scheduling */
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struct list_head work_list;
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struct delayed_work dwork; /* work item used for writeback */
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unsigned long dirty_sleep; /* last wait */
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struct list_head bdi_node; /* anchored at bdi->wb_list */
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#ifdef CONFIG_CGROUP_WRITEBACK
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struct percpu_ref refcnt; /* used only for !root wb's */
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struct fprop_local_percpu memcg_completions;
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struct cgroup_subsys_state *memcg_css; /* the associated memcg */
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struct cgroup_subsys_state *blkcg_css; /* and blkcg */
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struct list_head memcg_node; /* anchored at memcg->cgwb_list */
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struct list_head blkcg_node; /* anchored at blkcg->cgwb_list */
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union {
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struct work_struct release_work;
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struct rcu_head rcu;
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};
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#endif
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};
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struct backing_dev_info {
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u64 id;
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struct rb_node rb_node; /* keyed by ->id */
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struct list_head bdi_list;
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unsigned long ra_pages; /* max readahead in PAGE_SIZE units */
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unsigned long io_pages; /* max allowed IO size */
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struct kref refcnt; /* Reference counter for the structure */
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unsigned int capabilities; /* Device capabilities */
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unsigned int min_ratio;
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unsigned int max_ratio, max_prop_frac;
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/*
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* Sum of avg_write_bw of wbs with dirty inodes. > 0 if there are
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* any dirty wbs, which is depended upon by bdi_has_dirty().
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*/
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atomic_long_t tot_write_bandwidth;
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struct bdi_writeback wb; /* the root writeback info for this bdi */
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struct list_head wb_list; /* list of all wbs */
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#ifdef CONFIG_CGROUP_WRITEBACK
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struct radix_tree_root cgwb_tree; /* radix tree of active cgroup wbs */
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struct mutex cgwb_release_mutex; /* protect shutdown of wb structs */
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struct rw_semaphore wb_switch_rwsem; /* no cgwb switch while syncing */
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#endif
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wait_queue_head_t wb_waitq;
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struct device *dev;
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char dev_name[64];
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struct device *owner;
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struct timer_list laptop_mode_wb_timer;
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#ifdef CONFIG_DEBUG_FS
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struct dentry *debug_dir;
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#endif
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};
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enum {
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BLK_RW_ASYNC = 0,
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BLK_RW_SYNC = 1,
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};
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void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
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void set_bdi_congested(struct backing_dev_info *bdi, int sync);
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struct wb_lock_cookie {
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bool locked;
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unsigned long flags;
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};
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#ifdef CONFIG_CGROUP_WRITEBACK
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/**
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* wb_tryget - try to increment a wb's refcount
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* @wb: bdi_writeback to get
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*/
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static inline bool wb_tryget(struct bdi_writeback *wb)
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{
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if (wb != &wb->bdi->wb)
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return percpu_ref_tryget(&wb->refcnt);
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return true;
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}
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/**
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* wb_get - increment a wb's refcount
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* @wb: bdi_writeback to get
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*/
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static inline void wb_get(struct bdi_writeback *wb)
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{
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if (wb != &wb->bdi->wb)
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percpu_ref_get(&wb->refcnt);
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}
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/**
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* wb_put - decrement a wb's refcount
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* @wb: bdi_writeback to put
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*/
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static inline void wb_put(struct bdi_writeback *wb)
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{
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if (WARN_ON_ONCE(!wb->bdi)) {
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/*
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* A driver bug might cause a file to be removed before bdi was
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* initialized.
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*/
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return;
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}
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if (wb != &wb->bdi->wb)
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percpu_ref_put(&wb->refcnt);
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}
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/**
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* wb_dying - is a wb dying?
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* @wb: bdi_writeback of interest
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*
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* Returns whether @wb is unlinked and being drained.
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*/
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static inline bool wb_dying(struct bdi_writeback *wb)
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{
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return percpu_ref_is_dying(&wb->refcnt);
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}
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#else /* CONFIG_CGROUP_WRITEBACK */
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static inline bool wb_tryget(struct bdi_writeback *wb)
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{
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return true;
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}
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static inline void wb_get(struct bdi_writeback *wb)
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{
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}
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static inline void wb_put(struct bdi_writeback *wb)
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{
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}
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static inline bool wb_dying(struct bdi_writeback *wb)
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{
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return false;
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}
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#endif /* CONFIG_CGROUP_WRITEBACK */
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#endif /* __LINUX_BACKING_DEV_DEFS_H */
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