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434 lines
11 KiB
434 lines
11 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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/* |
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* include/linux/backing-dev.h |
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* |
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* low-level device information and state which is propagated up through |
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* to high-level code. |
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*/ |
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#ifndef _LINUX_BACKING_DEV_H |
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#define _LINUX_BACKING_DEV_H |
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#include <linux/kernel.h> |
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#include <linux/fs.h> |
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#include <linux/sched.h> |
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#include <linux/blkdev.h> |
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#include <linux/device.h> |
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#include <linux/writeback.h> |
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#include <linux/blk-cgroup.h> |
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#include <linux/backing-dev-defs.h> |
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#include <linux/slab.h> |
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static inline struct backing_dev_info *bdi_get(struct backing_dev_info *bdi) |
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{ |
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kref_get(&bdi->refcnt); |
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return bdi; |
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} |
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struct backing_dev_info *bdi_get_by_id(u64 id); |
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void bdi_put(struct backing_dev_info *bdi); |
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__printf(2, 3) |
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int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...); |
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__printf(2, 0) |
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int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, |
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va_list args); |
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void bdi_set_owner(struct backing_dev_info *bdi, struct device *owner); |
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void bdi_unregister(struct backing_dev_info *bdi); |
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struct backing_dev_info *bdi_alloc(int node_id); |
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void wb_start_background_writeback(struct bdi_writeback *wb); |
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void wb_workfn(struct work_struct *work); |
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void wb_wakeup_delayed(struct bdi_writeback *wb); |
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void wb_wait_for_completion(struct wb_completion *done); |
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extern spinlock_t bdi_lock; |
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extern struct list_head bdi_list; |
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extern struct workqueue_struct *bdi_wq; |
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extern struct workqueue_struct *bdi_async_bio_wq; |
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static inline bool wb_has_dirty_io(struct bdi_writeback *wb) |
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{ |
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return test_bit(WB_has_dirty_io, &wb->state); |
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} |
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static inline bool bdi_has_dirty_io(struct backing_dev_info *bdi) |
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{ |
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/* |
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* @bdi->tot_write_bandwidth is guaranteed to be > 0 if there are |
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* any dirty wbs. See wb_update_write_bandwidth(). |
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*/ |
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return atomic_long_read(&bdi->tot_write_bandwidth); |
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} |
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static inline void __add_wb_stat(struct bdi_writeback *wb, |
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enum wb_stat_item item, s64 amount) |
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{ |
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percpu_counter_add_batch(&wb->stat[item], amount, WB_STAT_BATCH); |
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} |
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static inline void inc_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) |
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{ |
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__add_wb_stat(wb, item, 1); |
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} |
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static inline void dec_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) |
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{ |
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__add_wb_stat(wb, item, -1); |
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} |
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static inline s64 wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) |
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{ |
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return percpu_counter_read_positive(&wb->stat[item]); |
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} |
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static inline s64 wb_stat_sum(struct bdi_writeback *wb, enum wb_stat_item item) |
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{ |
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return percpu_counter_sum_positive(&wb->stat[item]); |
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} |
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extern void wb_writeout_inc(struct bdi_writeback *wb); |
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/* |
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* maximal error of a stat counter. |
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*/ |
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static inline unsigned long wb_stat_error(void) |
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{ |
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#ifdef CONFIG_SMP |
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return nr_cpu_ids * WB_STAT_BATCH; |
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#else |
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return 1; |
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#endif |
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} |
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int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio); |
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int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); |
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/* |
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* Flags in backing_dev_info::capability |
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* |
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* BDI_CAP_WRITEBACK: Supports dirty page writeback, and dirty pages |
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* should contribute to accounting |
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* BDI_CAP_WRITEBACK_ACCT: Automatically account writeback pages |
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* BDI_CAP_STRICTLIMIT: Keep number of dirty pages below bdi threshold |
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*/ |
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#define BDI_CAP_WRITEBACK (1 << 0) |
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#define BDI_CAP_WRITEBACK_ACCT (1 << 1) |
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#define BDI_CAP_STRICTLIMIT (1 << 2) |
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extern struct backing_dev_info noop_backing_dev_info; |
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/** |
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* writeback_in_progress - determine whether there is writeback in progress |
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* @wb: bdi_writeback of interest |
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* |
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* Determine whether there is writeback waiting to be handled against a |
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* bdi_writeback. |
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*/ |
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static inline bool writeback_in_progress(struct bdi_writeback *wb) |
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{ |
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return test_bit(WB_writeback_running, &wb->state); |
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} |
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static inline struct backing_dev_info *inode_to_bdi(struct inode *inode) |
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{ |
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struct super_block *sb; |
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if (!inode) |
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return &noop_backing_dev_info; |
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sb = inode->i_sb; |
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#ifdef CONFIG_BLOCK |
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if (sb_is_blkdev_sb(sb)) |
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return I_BDEV(inode)->bd_bdi; |
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#endif |
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return sb->s_bdi; |
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} |
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static inline int wb_congested(struct bdi_writeback *wb, int cong_bits) |
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{ |
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return wb->congested & cong_bits; |
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} |
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long congestion_wait(int sync, long timeout); |
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long wait_iff_congested(int sync, long timeout); |
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static inline bool mapping_can_writeback(struct address_space *mapping) |
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{ |
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return inode_to_bdi(mapping->host)->capabilities & BDI_CAP_WRITEBACK; |
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} |
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static inline int bdi_sched_wait(void *word) |
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{ |
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schedule(); |
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return 0; |
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} |
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#ifdef CONFIG_CGROUP_WRITEBACK |
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struct bdi_writeback *wb_get_lookup(struct backing_dev_info *bdi, |
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struct cgroup_subsys_state *memcg_css); |
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struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi, |
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struct cgroup_subsys_state *memcg_css, |
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gfp_t gfp); |
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void wb_memcg_offline(struct mem_cgroup *memcg); |
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void wb_blkcg_offline(struct blkcg *blkcg); |
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int inode_congested(struct inode *inode, int cong_bits); |
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/** |
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* inode_cgwb_enabled - test whether cgroup writeback is enabled on an inode |
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* @inode: inode of interest |
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* |
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* Cgroup writeback requires support from the filesystem. Also, both memcg and |
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* iocg have to be on the default hierarchy. Test whether all conditions are |
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* met. |
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* |
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* Note that the test result may change dynamically on the same inode |
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* depending on how memcg and iocg are configured. |
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*/ |
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static inline bool inode_cgwb_enabled(struct inode *inode) |
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{ |
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struct backing_dev_info *bdi = inode_to_bdi(inode); |
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return cgroup_subsys_on_dfl(memory_cgrp_subsys) && |
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cgroup_subsys_on_dfl(io_cgrp_subsys) && |
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(bdi->capabilities & BDI_CAP_WRITEBACK) && |
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(inode->i_sb->s_iflags & SB_I_CGROUPWB); |
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} |
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/** |
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* wb_find_current - find wb for %current on a bdi |
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* @bdi: bdi of interest |
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* |
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* Find the wb of @bdi which matches both the memcg and blkcg of %current. |
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* Must be called under rcu_read_lock() which protects the returend wb. |
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* NULL if not found. |
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*/ |
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static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi) |
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{ |
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struct cgroup_subsys_state *memcg_css; |
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struct bdi_writeback *wb; |
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memcg_css = task_css(current, memory_cgrp_id); |
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if (!memcg_css->parent) |
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return &bdi->wb; |
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wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id); |
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/* |
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* %current's blkcg equals the effective blkcg of its memcg. No |
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* need to use the relatively expensive cgroup_get_e_css(). |
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*/ |
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if (likely(wb && wb->blkcg_css == task_css(current, io_cgrp_id))) |
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return wb; |
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return NULL; |
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} |
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/** |
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* wb_get_create_current - get or create wb for %current on a bdi |
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* @bdi: bdi of interest |
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* @gfp: allocation mask |
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* |
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* Equivalent to wb_get_create() on %current's memcg. This function is |
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* called from a relatively hot path and optimizes the common cases using |
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* wb_find_current(). |
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*/ |
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static inline struct bdi_writeback * |
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wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp) |
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{ |
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struct bdi_writeback *wb; |
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rcu_read_lock(); |
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wb = wb_find_current(bdi); |
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if (wb && unlikely(!wb_tryget(wb))) |
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wb = NULL; |
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rcu_read_unlock(); |
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if (unlikely(!wb)) { |
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struct cgroup_subsys_state *memcg_css; |
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memcg_css = task_get_css(current, memory_cgrp_id); |
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wb = wb_get_create(bdi, memcg_css, gfp); |
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css_put(memcg_css); |
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} |
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return wb; |
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} |
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/** |
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* inode_to_wb_is_valid - test whether an inode has a wb associated |
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* @inode: inode of interest |
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* |
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* Returns %true if @inode has a wb associated. May be called without any |
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* locking. |
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*/ |
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static inline bool inode_to_wb_is_valid(struct inode *inode) |
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{ |
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return inode->i_wb; |
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} |
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/** |
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* inode_to_wb - determine the wb of an inode |
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* @inode: inode of interest |
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* |
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* Returns the wb @inode is currently associated with. The caller must be |
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* holding either @inode->i_lock, the i_pages lock, or the |
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* associated wb's list_lock. |
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*/ |
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static inline struct bdi_writeback *inode_to_wb(const struct inode *inode) |
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{ |
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#ifdef CONFIG_LOCKDEP |
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WARN_ON_ONCE(debug_locks && |
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(!lockdep_is_held(&inode->i_lock) && |
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!lockdep_is_held(&inode->i_mapping->i_pages.xa_lock) && |
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!lockdep_is_held(&inode->i_wb->list_lock))); |
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#endif |
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return inode->i_wb; |
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} |
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/** |
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* unlocked_inode_to_wb_begin - begin unlocked inode wb access transaction |
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* @inode: target inode |
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* @cookie: output param, to be passed to the end function |
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* |
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* The caller wants to access the wb associated with @inode but isn't |
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* holding inode->i_lock, the i_pages lock or wb->list_lock. This |
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* function determines the wb associated with @inode and ensures that the |
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* association doesn't change until the transaction is finished with |
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* unlocked_inode_to_wb_end(). |
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* |
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* The caller must call unlocked_inode_to_wb_end() with *@cookie afterwards and |
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* can't sleep during the transaction. IRQs may or may not be disabled on |
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* return. |
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*/ |
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static inline struct bdi_writeback * |
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unlocked_inode_to_wb_begin(struct inode *inode, struct wb_lock_cookie *cookie) |
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{ |
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rcu_read_lock(); |
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/* |
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* Paired with store_release in inode_switch_wbs_work_fn() and |
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* ensures that we see the new wb if we see cleared I_WB_SWITCH. |
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*/ |
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cookie->locked = smp_load_acquire(&inode->i_state) & I_WB_SWITCH; |
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if (unlikely(cookie->locked)) |
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xa_lock_irqsave(&inode->i_mapping->i_pages, cookie->flags); |
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/* |
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* Protected by either !I_WB_SWITCH + rcu_read_lock() or the i_pages |
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* lock. inode_to_wb() will bark. Deref directly. |
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*/ |
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return inode->i_wb; |
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} |
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/** |
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* unlocked_inode_to_wb_end - end inode wb access transaction |
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* @inode: target inode |
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* @cookie: @cookie from unlocked_inode_to_wb_begin() |
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*/ |
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static inline void unlocked_inode_to_wb_end(struct inode *inode, |
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struct wb_lock_cookie *cookie) |
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{ |
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if (unlikely(cookie->locked)) |
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xa_unlock_irqrestore(&inode->i_mapping->i_pages, cookie->flags); |
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rcu_read_unlock(); |
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} |
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#else /* CONFIG_CGROUP_WRITEBACK */ |
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static inline bool inode_cgwb_enabled(struct inode *inode) |
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{ |
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return false; |
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} |
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static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi) |
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{ |
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return &bdi->wb; |
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} |
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static inline struct bdi_writeback * |
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wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp) |
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{ |
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return &bdi->wb; |
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} |
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static inline bool inode_to_wb_is_valid(struct inode *inode) |
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{ |
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return true; |
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} |
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static inline struct bdi_writeback *inode_to_wb(struct inode *inode) |
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{ |
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return &inode_to_bdi(inode)->wb; |
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} |
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static inline struct bdi_writeback * |
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unlocked_inode_to_wb_begin(struct inode *inode, struct wb_lock_cookie *cookie) |
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{ |
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return inode_to_wb(inode); |
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} |
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static inline void unlocked_inode_to_wb_end(struct inode *inode, |
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struct wb_lock_cookie *cookie) |
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{ |
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} |
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static inline void wb_memcg_offline(struct mem_cgroup *memcg) |
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{ |
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} |
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static inline void wb_blkcg_offline(struct blkcg *blkcg) |
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{ |
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} |
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static inline int inode_congested(struct inode *inode, int cong_bits) |
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{ |
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return wb_congested(&inode_to_bdi(inode)->wb, cong_bits); |
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} |
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#endif /* CONFIG_CGROUP_WRITEBACK */ |
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static inline int inode_read_congested(struct inode *inode) |
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{ |
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return inode_congested(inode, 1 << WB_sync_congested); |
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} |
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static inline int inode_write_congested(struct inode *inode) |
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{ |
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return inode_congested(inode, 1 << WB_async_congested); |
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} |
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static inline int inode_rw_congested(struct inode *inode) |
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{ |
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return inode_congested(inode, (1 << WB_sync_congested) | |
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(1 << WB_async_congested)); |
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} |
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static inline int bdi_congested(struct backing_dev_info *bdi, int cong_bits) |
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{ |
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return wb_congested(&bdi->wb, cong_bits); |
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} |
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static inline int bdi_read_congested(struct backing_dev_info *bdi) |
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{ |
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return bdi_congested(bdi, 1 << WB_sync_congested); |
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} |
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static inline int bdi_write_congested(struct backing_dev_info *bdi) |
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{ |
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return bdi_congested(bdi, 1 << WB_async_congested); |
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} |
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static inline int bdi_rw_congested(struct backing_dev_info *bdi) |
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{ |
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return bdi_congested(bdi, (1 << WB_sync_congested) | |
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(1 << WB_async_congested)); |
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} |
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const char *bdi_dev_name(struct backing_dev_info *bdi); |
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#endif /* _LINUX_BACKING_DEV_H */
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