From 9cc63f8bcd560c760d0b12e15bba8f81c86237cf Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 14 Aug 2026 15:43:51 -0700 Subject: Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEAD Changes: Make expedited grace periods expedite normal RCU callbacks Miscellaneous fixes: * Improve diagnostic output with character task states. * Mark accesses to inform KCSAN of concurrency design. * Move from kmalloc() to kmalloc_obj(). * Documentation updates. * Improve handling of RCU deferred quiescent states. * Clean up unused function arguments and structure fields. * Reduce show_rcu_gp_kthreads() stack space. Tasks RCU updates: * Clean up after SRCU re-implementation of Tasks Trace RCU. * Mark accesses to inform KCSAN of concurrency design. * Add ->lazy_timer status to diagnostic output. * Remove an unnecessary memory barrier. * Fix a data race, courtesy of KCSAN. * Documentation updates. * Convert cond_resched_tasks_rcu_qs() from macro to static inline function. SRCU updates: * Add Rust helpers for SRCU. * Avoid losing queued work at cleanup_srcu_struct() time. Torture-test updates: * Preparation work for immediate RCU priority deboosting. * Test RCU readers from real interrupt handlers (as opposed to softirq). * Simplify code through use of cpumask_next_wrap(). * Improve diagnostic output with character task states. * Add rcutorture.nwriters parameter to allow lightweight stall testing, and rcutorture.stall_only to make doing so easier. * Test an RCU Tasks Trace grace period implying an RCU grace period. * Make RCU Tasks Trace torturing track reader batches. * Fix a data race, courtesy of KCSAN. * Plug a shuffle_tmp_mask memory leak on kthread spawn failure. --- drivers/md/bcache/writeback.h | 155 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 155 insertions(+) create mode 100644 drivers/md/bcache/writeback.h (limited to 'drivers/md/bcache/writeback.h') diff --git a/drivers/md/bcache/writeback.h b/drivers/md/bcache/writeback.h new file mode 100644 index 000000000..31df71695 --- /dev/null +++ b/drivers/md/bcache/writeback.h @@ -0,0 +1,155 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _BCACHE_WRITEBACK_H +#define _BCACHE_WRITEBACK_H + +#define CUTOFF_WRITEBACK 40 +#define CUTOFF_WRITEBACK_SYNC 70 + +#define CUTOFF_WRITEBACK_MAX 70 +#define CUTOFF_WRITEBACK_SYNC_MAX 90 + +#define MAX_WRITEBACKS_IN_PASS 5 +#define MAX_WRITESIZE_IN_PASS 5000 /* *512b */ + +#define WRITEBACK_RATE_UPDATE_SECS_MAX 60 +#define WRITEBACK_RATE_UPDATE_SECS_DEFAULT 5 + +#define BCH_AUTO_GC_DIRTY_THRESHOLD 50 + +#define BCH_WRITEBACK_FRAGMENT_THRESHOLD_LOW 50 +#define BCH_WRITEBACK_FRAGMENT_THRESHOLD_MID 57 +#define BCH_WRITEBACK_FRAGMENT_THRESHOLD_HIGH 64 + +#define BCH_DIRTY_INIT_THRD_MAX 12 +/* + * 14 (16384ths) is chosen here as something that each backing device + * should be a reasonable fraction of the share, and not to blow up + * until individual backing devices are a petabyte. + */ +#define WRITEBACK_SHARE_SHIFT 14 + +struct bch_dirty_init_state; +struct dirty_init_thrd_info { + struct bch_dirty_init_state *state; + struct task_struct *thread; +}; + +struct bch_dirty_init_state { + struct cache_set *c; + struct bcache_device *d; + int total_threads; + int key_idx; + spinlock_t idx_lock; + atomic_t started; + atomic_t enough; + wait_queue_head_t wait; + struct dirty_init_thrd_info infos[BCH_DIRTY_INIT_THRD_MAX]; +}; + +static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d) +{ + uint64_t i, ret = 0; + + for (i = 0; i < d->nr_stripes; i++) + ret += atomic_read(d->stripe_sectors_dirty + i); + + return ret; +} + +static inline int offset_to_stripe(struct bcache_device *d, + uint64_t offset) +{ + do_div(offset, d->stripe_size); + + /* d->nr_stripes is in range [1, INT_MAX] */ + if (unlikely(offset >= d->nr_stripes)) { + pr_err("Invalid stripe %llu (>= nr_stripes %d).\n", + offset, d->nr_stripes); + return -EINVAL; + } + + /* + * Here offset is definitly smaller than INT_MAX, + * return it as int will never overflow. + */ + return offset; +} + +static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc, + uint64_t offset, + unsigned int nr_sectors) +{ + int stripe = offset_to_stripe(&dc->disk, offset); + + if (stripe < 0) + return false; + + while (1) { + if (atomic_read(dc->disk.stripe_sectors_dirty + stripe)) + return true; + + if (nr_sectors <= dc->disk.stripe_size) + return false; + + nr_sectors -= dc->disk.stripe_size; + stripe++; + } +} + +extern unsigned int bch_cutoff_writeback; +extern unsigned int bch_cutoff_writeback_sync; + +static inline bool should_writeback(struct cached_dev *dc, struct bio *bio, + unsigned int cache_mode, bool would_skip) +{ + unsigned int in_use = dc->disk.c->gc_stats.in_use; + + if (cache_mode != CACHE_MODE_WRITEBACK || + test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) || + in_use > bch_cutoff_writeback_sync) + return false; + + if (bio_op(bio) == REQ_OP_DISCARD) + return false; + + if (dc->partial_stripes_expensive && + bcache_dev_stripe_dirty(dc, bio->bi_iter.bi_sector, + bio_sectors(bio))) + return true; + + if (would_skip) + return false; + + return (op_is_sync(bio->bi_opf) || + bio->bi_opf & (REQ_META|REQ_PRIO) || + in_use <= bch_cutoff_writeback); +} + +static inline void bch_writeback_queue(struct cached_dev *dc) +{ + if (!IS_ERR_OR_NULL(dc->writeback_thread)) + wake_up_process(dc->writeback_thread); +} + +static inline void bch_writeback_add(struct cached_dev *dc) +{ + if (!atomic_read(&dc->has_dirty) && + !atomic_xchg(&dc->has_dirty, 1)) { + if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) { + SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY); + /* XXX: should do this synchronously */ + bch_write_bdev_super(dc, NULL); + } + + bch_writeback_queue(dc); + } +} + +void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned int inode, + uint64_t offset, int nr_sectors); + +void bch_sectors_dirty_init(struct bcache_device *d); +void bch_cached_dev_writeback_init(struct cached_dev *dc); +int bch_cached_dev_writeback_start(struct cached_dev *dc); + +#endif -- cgit v1.3.1