.name = "noop",
.capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
};
+EXPORT_SYMBOL_GPL(noop_backing_dev_info);
static struct class *bdi_class;
struct bdi_writeback *wb = &bdi->wb;
unsigned long background_thresh;
unsigned long dirty_thresh;
- unsigned long bdi_thresh;
+ unsigned long wb_thresh;
unsigned long nr_dirty, nr_io, nr_more_io, nr_dirty_time;
struct inode *inode;
nr_dirty = nr_io = nr_more_io = nr_dirty_time = 0;
spin_lock(&wb->list_lock);
- list_for_each_entry(inode, &wb->b_dirty, i_wb_list)
+ list_for_each_entry(inode, &wb->b_dirty, i_io_list)
nr_dirty++;
- list_for_each_entry(inode, &wb->b_io, i_wb_list)
+ list_for_each_entry(inode, &wb->b_io, i_io_list)
nr_io++;
- list_for_each_entry(inode, &wb->b_more_io, i_wb_list)
+ list_for_each_entry(inode, &wb->b_more_io, i_io_list)
nr_more_io++;
- list_for_each_entry(inode, &wb->b_dirty_time, i_wb_list)
+ list_for_each_entry(inode, &wb->b_dirty_time, i_io_list)
if (inode->i_state & I_DIRTY_TIME)
nr_dirty_time++;
spin_unlock(&wb->list_lock);
global_dirty_limits(&background_thresh, &dirty_thresh);
- bdi_thresh = bdi_dirty_limit(bdi, dirty_thresh);
+ wb_thresh = wb_calc_thresh(wb, dirty_thresh);
#define K(x) ((x) << (PAGE_SHIFT - 10))
seq_printf(m,
"b_dirty_time: %10lu\n"
"bdi_list: %10u\n"
"state: %10lx\n",
- (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)),
- (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)),
- K(bdi_thresh),
+ (unsigned long) K(wb_stat(wb, WB_WRITEBACK)),
+ (unsigned long) K(wb_stat(wb, WB_RECLAIMABLE)),
+ K(wb_thresh),
K(dirty_thresh),
K(background_thresh),
- (unsigned long) K(bdi_stat(bdi, BDI_DIRTIED)),
- (unsigned long) K(bdi_stat(bdi, BDI_WRITTEN)),
- (unsigned long) K(bdi->write_bandwidth),
+ (unsigned long) K(wb_stat(wb, WB_DIRTIED)),
+ (unsigned long) K(wb_stat(wb, WB_WRITTEN)),
+ (unsigned long) K(wb->write_bandwidth),
nr_dirty,
nr_io,
nr_more_io,
nr_dirty_time,
- !list_empty(&bdi->bdi_list), bdi->state);
+ !list_empty(&bdi->bdi_list), bdi->wb.state);
#undef K
return 0;
}
subsys_initcall(default_bdi_init);
-int bdi_has_dirty_io(struct backing_dev_info *bdi)
-{
- return wb_has_dirty_io(&bdi->wb);
-}
-
/*
- * This function is used when the first inode for this bdi is marked dirty. It
+ * This function is used when the first inode for this wb is marked dirty. It
* wakes-up the corresponding bdi thread which should then take care of the
* periodic background write-out of dirty inodes. Since the write-out would
* starts only 'dirty_writeback_interval' centisecs from now anyway, we just
* We have to be careful not to postpone flush work if it is scheduled for
* earlier. Thus we use queue_delayed_work().
*/
-void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi)
+void wb_wakeup_delayed(struct bdi_writeback *wb)
{
unsigned long timeout;
timeout = msecs_to_jiffies(dirty_writeback_interval * 10);
- spin_lock_bh(&bdi->wb_lock);
- if (test_bit(BDI_registered, &bdi->state))
- queue_delayed_work(bdi_wq, &bdi->wb.dwork, timeout);
- spin_unlock_bh(&bdi->wb_lock);
+ spin_lock_bh(&wb->work_lock);
+ if (test_bit(WB_registered, &wb->state))
+ queue_delayed_work(bdi_wq, &wb->dwork, timeout);
+ spin_unlock_bh(&wb->work_lock);
}
/*
- * Remove bdi from bdi_list, and ensure that it is no longer visible
+ * Initial write bandwidth: 100 MB/s
*/
-static void bdi_remove_from_list(struct backing_dev_info *bdi)
+#define INIT_BW (100 << (20 - PAGE_SHIFT))
+
+static int wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi,
+ int blkcg_id, gfp_t gfp)
{
- spin_lock_bh(&bdi_lock);
- list_del_rcu(&bdi->bdi_list);
- spin_unlock_bh(&bdi_lock);
+ int i, err;
- synchronize_rcu_expedited();
-}
+ memset(wb, 0, sizeof(*wb));
-int bdi_register(struct backing_dev_info *bdi, struct device *parent,
- const char *fmt, ...)
-{
- va_list args;
- struct device *dev;
+ wb->bdi = bdi;
+ wb->last_old_flush = jiffies;
+ INIT_LIST_HEAD(&wb->b_dirty);
+ INIT_LIST_HEAD(&wb->b_io);
+ INIT_LIST_HEAD(&wb->b_more_io);
+ INIT_LIST_HEAD(&wb->b_dirty_time);
+ spin_lock_init(&wb->list_lock);
- if (bdi->dev) /* The driver needs to use separate queues per device */
- return 0;
+ wb->bw_time_stamp = jiffies;
+ wb->balanced_dirty_ratelimit = INIT_BW;
+ wb->dirty_ratelimit = INIT_BW;
+ wb->write_bandwidth = INIT_BW;
+ wb->avg_write_bandwidth = INIT_BW;
- va_start(args, fmt);
- dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args);
- va_end(args);
- if (IS_ERR(dev))
- return PTR_ERR(dev);
+ spin_lock_init(&wb->work_lock);
+ INIT_LIST_HEAD(&wb->work_list);
+ INIT_DELAYED_WORK(&wb->dwork, wb_workfn);
- bdi->dev = dev;
+ wb->congested = wb_congested_get_create(bdi, blkcg_id, gfp);
+ if (!wb->congested)
+ return -ENOMEM;
- bdi_debug_register(bdi, dev_name(dev));
- set_bit(BDI_registered, &bdi->state);
+ err = fprop_local_init_percpu(&wb->completions, gfp);
+ if (err)
+ goto out_put_cong;
- spin_lock_bh(&bdi_lock);
- list_add_tail_rcu(&bdi->bdi_list, &bdi_list);
- spin_unlock_bh(&bdi_lock);
+ for (i = 0; i < NR_WB_STAT_ITEMS; i++) {
+ err = percpu_counter_init(&wb->stat[i], 0, gfp);
+ if (err)
+ goto out_destroy_stat;
+ }
- trace_writeback_bdi_register(bdi);
return 0;
-}
-EXPORT_SYMBOL(bdi_register);
-int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev)
-{
- return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev));
+out_destroy_stat:
+ while (--i)
+ percpu_counter_destroy(&wb->stat[i]);
+ fprop_local_destroy_percpu(&wb->completions);
+out_put_cong:
+ wb_congested_put(wb->congested);
+ return err;
}
-EXPORT_SYMBOL(bdi_register_dev);
/*
* Remove bdi from the global list and shutdown any threads we have running
*/
-static void bdi_wb_shutdown(struct backing_dev_info *bdi)
+static void wb_shutdown(struct bdi_writeback *wb)
{
/* Make sure nobody queues further work */
- spin_lock_bh(&bdi->wb_lock);
- if (!test_and_clear_bit(BDI_registered, &bdi->state)) {
- spin_unlock_bh(&bdi->wb_lock);
+ spin_lock_bh(&wb->work_lock);
+ if (!test_and_clear_bit(WB_registered, &wb->state)) {
+ spin_unlock_bh(&wb->work_lock);
return;
}
- spin_unlock_bh(&bdi->wb_lock);
+ spin_unlock_bh(&wb->work_lock);
/*
- * Make sure nobody finds us on the bdi_list anymore
+ * Drain work list and shutdown the delayed_work. !WB_registered
+ * tells wb_workfn() that @wb is dying and its work_list needs to
+ * be drained no matter what.
*/
- bdi_remove_from_list(bdi);
+ mod_delayed_work(bdi_wq, &wb->dwork, 0);
+ flush_delayed_work(&wb->dwork);
+ WARN_ON(!list_empty(&wb->work_list));
+}
+
+static void wb_exit(struct bdi_writeback *wb)
+{
+ int i;
+
+ WARN_ON(delayed_work_pending(&wb->dwork));
+
+ for (i = 0; i < NR_WB_STAT_ITEMS; i++)
+ percpu_counter_destroy(&wb->stat[i]);
+
+ fprop_local_destroy_percpu(&wb->completions);
+ wb_congested_put(wb->congested);
+}
+
+#ifdef CONFIG_CGROUP_WRITEBACK
+
+#include <linux/memcontrol.h>
+
+/*
+ * cgwb_lock protects bdi->cgwb_tree, bdi->cgwb_congested_tree,
+ * blkcg->cgwb_list, and memcg->cgwb_list. bdi->cgwb_tree is also RCU
+ * protected. cgwb_release_wait is used to wait for the completion of cgwb
+ * releases from bdi destruction path.
+ */
+static DEFINE_SPINLOCK(cgwb_lock);
+static DECLARE_WAIT_QUEUE_HEAD(cgwb_release_wait);
+
+/**
+ * wb_congested_get_create - get or create a wb_congested
+ * @bdi: associated bdi
+ * @blkcg_id: ID of the associated blkcg
+ * @gfp: allocation mask
+ *
+ * Look up the wb_congested for @blkcg_id on @bdi. If missing, create one.
+ * The returned wb_congested has its reference count incremented. Returns
+ * NULL on failure.
+ */
+struct bdi_writeback_congested *
+wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp)
+{
+ struct bdi_writeback_congested *new_congested = NULL, *congested;
+ struct rb_node **node, *parent;
+ unsigned long flags;
+retry:
+ spin_lock_irqsave(&cgwb_lock, flags);
+
+ node = &bdi->cgwb_congested_tree.rb_node;
+ parent = NULL;
+
+ while (*node != NULL) {
+ parent = *node;
+ congested = container_of(parent, struct bdi_writeback_congested,
+ rb_node);
+ if (congested->blkcg_id < blkcg_id)
+ node = &parent->rb_left;
+ else if (congested->blkcg_id > blkcg_id)
+ node = &parent->rb_right;
+ else
+ goto found;
+ }
+
+ if (new_congested) {
+ /* !found and storage for new one already allocated, insert */
+ congested = new_congested;
+ new_congested = NULL;
+ rb_link_node(&congested->rb_node, parent, node);
+ rb_insert_color(&congested->rb_node, &bdi->cgwb_congested_tree);
+ goto found;
+ }
+
+ spin_unlock_irqrestore(&cgwb_lock, flags);
+
+ /* allocate storage for new one and retry */
+ new_congested = kzalloc(sizeof(*new_congested), gfp);
+ if (!new_congested)
+ return NULL;
+
+ atomic_set(&new_congested->refcnt, 0);
+ new_congested->bdi = bdi;
+ new_congested->blkcg_id = blkcg_id;
+ goto retry;
+
+found:
+ atomic_inc(&congested->refcnt);
+ spin_unlock_irqrestore(&cgwb_lock, flags);
+ kfree(new_congested);
+ return congested;
+}
+
+/**
+ * wb_congested_put - put a wb_congested
+ * @congested: wb_congested to put
+ *
+ * Put @congested and destroy it if the refcnt reaches zero.
+ */
+void wb_congested_put(struct bdi_writeback_congested *congested)
+{
+ unsigned long flags;
+
+ local_irq_save_nort(flags);
+ if (!atomic_dec_and_lock(&congested->refcnt, &cgwb_lock)) {
+ local_irq_restore_nort(flags);
+ return;
+ }
+
+ /* bdi might already have been destroyed leaving @congested unlinked */
+ if (congested->bdi) {
+ rb_erase(&congested->rb_node,
+ &congested->bdi->cgwb_congested_tree);
+ congested->bdi = NULL;
+ }
+
+ spin_unlock_irqrestore(&cgwb_lock, flags);
+ kfree(congested);
+}
+
+static void cgwb_release_workfn(struct work_struct *work)
+{
+ struct bdi_writeback *wb = container_of(work, struct bdi_writeback,
+ release_work);
+ struct backing_dev_info *bdi = wb->bdi;
+
+ spin_lock_irq(&cgwb_lock);
+ list_del_rcu(&wb->bdi_node);
+ spin_unlock_irq(&cgwb_lock);
+
+ wb_shutdown(wb);
+
+ css_put(wb->memcg_css);
+ css_put(wb->blkcg_css);
+
+ fprop_local_destroy_percpu(&wb->memcg_completions);
+ percpu_ref_exit(&wb->refcnt);
+ wb_exit(wb);
+ kfree_rcu(wb, rcu);
+
+ if (atomic_dec_and_test(&bdi->usage_cnt))
+ wake_up_all(&cgwb_release_wait);
+}
+
+static void cgwb_release(struct percpu_ref *refcnt)
+{
+ struct bdi_writeback *wb = container_of(refcnt, struct bdi_writeback,
+ refcnt);
+ schedule_work(&wb->release_work);
+}
+
+static void cgwb_kill(struct bdi_writeback *wb)
+{
+ lockdep_assert_held(&cgwb_lock);
+
+ WARN_ON(!radix_tree_delete(&wb->bdi->cgwb_tree, wb->memcg_css->id));
+ list_del(&wb->memcg_node);
+ list_del(&wb->blkcg_node);
+ percpu_ref_kill(&wb->refcnt);
+}
+
+static int cgwb_create(struct backing_dev_info *bdi,
+ struct cgroup_subsys_state *memcg_css, gfp_t gfp)
+{
+ struct mem_cgroup *memcg;
+ struct cgroup_subsys_state *blkcg_css;
+ struct blkcg *blkcg;
+ struct list_head *memcg_cgwb_list, *blkcg_cgwb_list;
+ struct bdi_writeback *wb;
+ unsigned long flags;
+ int ret = 0;
+
+ memcg = mem_cgroup_from_css(memcg_css);
+ blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &io_cgrp_subsys);
+ blkcg = css_to_blkcg(blkcg_css);
+ memcg_cgwb_list = mem_cgroup_cgwb_list(memcg);
+ blkcg_cgwb_list = &blkcg->cgwb_list;
+
+ /* look up again under lock and discard on blkcg mismatch */
+ spin_lock_irqsave(&cgwb_lock, flags);
+ wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id);
+ if (wb && wb->blkcg_css != blkcg_css) {
+ cgwb_kill(wb);
+ wb = NULL;
+ }
+ spin_unlock_irqrestore(&cgwb_lock, flags);
+ if (wb)
+ goto out_put;
+
+ /* need to create a new one */
+ wb = kmalloc(sizeof(*wb), gfp);
+ if (!wb)
+ return -ENOMEM;
+
+ ret = wb_init(wb, bdi, blkcg_css->id, gfp);
+ if (ret)
+ goto err_free;
+
+ ret = percpu_ref_init(&wb->refcnt, cgwb_release, 0, gfp);
+ if (ret)
+ goto err_wb_exit;
+
+ ret = fprop_local_init_percpu(&wb->memcg_completions, gfp);
+ if (ret)
+ goto err_ref_exit;
+
+ wb->memcg_css = memcg_css;
+ wb->blkcg_css = blkcg_css;
+ INIT_WORK(&wb->release_work, cgwb_release_workfn);
+ set_bit(WB_registered, &wb->state);
/*
- * Drain work list and shutdown the delayed_work. At this point,
- * @bdi->bdi_list is empty telling bdi_Writeback_workfn() that @bdi
- * is dying and its work_list needs to be drained no matter what.
+ * The root wb determines the registered state of the whole bdi and
+ * memcg_cgwb_list and blkcg_cgwb_list's next pointers indicate
+ * whether they're still online. Don't link @wb if any is dead.
+ * See wb_memcg_offline() and wb_blkcg_offline().
*/
- mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0);
- flush_delayed_work(&bdi->wb.dwork);
+ ret = -ENODEV;
+ spin_lock_irqsave(&cgwb_lock, flags);
+ if (test_bit(WB_registered, &bdi->wb.state) &&
+ blkcg_cgwb_list->next && memcg_cgwb_list->next) {
+ /* we might have raced another instance of this function */
+ ret = radix_tree_insert(&bdi->cgwb_tree, memcg_css->id, wb);
+ if (!ret) {
+ atomic_inc(&bdi->usage_cnt);
+ list_add_tail_rcu(&wb->bdi_node, &bdi->wb_list);
+ list_add(&wb->memcg_node, memcg_cgwb_list);
+ list_add(&wb->blkcg_node, blkcg_cgwb_list);
+ css_get(memcg_css);
+ css_get(blkcg_css);
+ }
+ }
+ spin_unlock_irqrestore(&cgwb_lock, flags);
+ if (ret) {
+ if (ret == -EEXIST)
+ ret = 0;
+ goto err_fprop_exit;
+ }
+ goto out_put;
+
+err_fprop_exit:
+ fprop_local_destroy_percpu(&wb->memcg_completions);
+err_ref_exit:
+ percpu_ref_exit(&wb->refcnt);
+err_wb_exit:
+ wb_exit(wb);
+err_free:
+ kfree(wb);
+out_put:
+ css_put(blkcg_css);
+ return ret;
}
-static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
+/**
+ * wb_get_create - get wb for a given memcg, create if necessary
+ * @bdi: target bdi
+ * @memcg_css: cgroup_subsys_state of the target memcg (must have positive ref)
+ * @gfp: allocation mask to use
+ *
+ * Try to get the wb for @memcg_css on @bdi. If it doesn't exist, try to
+ * create one. The returned wb has its refcount incremented.
+ *
+ * This function uses css_get() on @memcg_css and thus expects its refcnt
+ * to be positive on invocation. IOW, rcu_read_lock() protection on
+ * @memcg_css isn't enough. try_get it before calling this function.
+ *
+ * A wb is keyed by its associated memcg. As blkcg implicitly enables
+ * memcg on the default hierarchy, memcg association is guaranteed to be
+ * more specific (equal or descendant to the associated blkcg) and thus can
+ * identify both the memcg and blkcg associations.
+ *
+ * Because the blkcg associated with a memcg may change as blkcg is enabled
+ * and disabled closer to root in the hierarchy, each wb keeps track of
+ * both the memcg and blkcg associated with it and verifies the blkcg on
+ * each lookup. On mismatch, the existing wb is discarded and a new one is
+ * created.
+ */
+struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi,
+ struct cgroup_subsys_state *memcg_css,
+ gfp_t gfp)
{
- memset(wb, 0, sizeof(*wb));
+ struct bdi_writeback *wb;
+
+ might_sleep_if(gfpflags_allow_blocking(gfp));
+
+ if (!memcg_css->parent)
+ return &bdi->wb;
+
+ do {
+ rcu_read_lock();
+ wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id);
+ if (wb) {
+ struct cgroup_subsys_state *blkcg_css;
+
+ /* see whether the blkcg association has changed */
+ blkcg_css = cgroup_get_e_css(memcg_css->cgroup,
+ &io_cgrp_subsys);
+ if (unlikely(wb->blkcg_css != blkcg_css ||
+ !wb_tryget(wb)))
+ wb = NULL;
+ css_put(blkcg_css);
+ }
+ rcu_read_unlock();
+ } while (!wb && !cgwb_create(bdi, memcg_css, gfp));
+
+ return wb;
+}
- wb->bdi = bdi;
- wb->last_old_flush = jiffies;
- INIT_LIST_HEAD(&wb->b_dirty);
- INIT_LIST_HEAD(&wb->b_io);
- INIT_LIST_HEAD(&wb->b_more_io);
- INIT_LIST_HEAD(&wb->b_dirty_time);
- spin_lock_init(&wb->list_lock);
- INIT_DELAYED_WORK(&wb->dwork, bdi_writeback_workfn);
+static int cgwb_bdi_init(struct backing_dev_info *bdi)
+{
+ int ret;
+
+ INIT_RADIX_TREE(&bdi->cgwb_tree, GFP_ATOMIC);
+ bdi->cgwb_congested_tree = RB_ROOT;
+ atomic_set(&bdi->usage_cnt, 1);
+
+ ret = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL);
+ if (!ret) {
+ bdi->wb.memcg_css = mem_cgroup_root_css;
+ bdi->wb.blkcg_css = blkcg_root_css;
+ }
+ return ret;
}
-/*
- * Initial write bandwidth: 100 MB/s
+static void cgwb_bdi_destroy(struct backing_dev_info *bdi)
+{
+ struct radix_tree_iter iter;
+ struct rb_node *rbn;
+ void **slot;
+
+ WARN_ON(test_bit(WB_registered, &bdi->wb.state));
+
+ spin_lock_irq(&cgwb_lock);
+
+ radix_tree_for_each_slot(slot, &bdi->cgwb_tree, &iter, 0)
+ cgwb_kill(*slot);
+
+ while ((rbn = rb_first(&bdi->cgwb_congested_tree))) {
+ struct bdi_writeback_congested *congested =
+ rb_entry(rbn, struct bdi_writeback_congested, rb_node);
+
+ rb_erase(rbn, &bdi->cgwb_congested_tree);
+ congested->bdi = NULL; /* mark @congested unlinked */
+ }
+
+ spin_unlock_irq(&cgwb_lock);
+
+ /*
+ * All cgwb's and their congested states must be shutdown and
+ * released before returning. Drain the usage counter to wait for
+ * all cgwb's and cgwb_congested's ever created on @bdi.
+ */
+ atomic_dec(&bdi->usage_cnt);
+ wait_event(cgwb_release_wait, !atomic_read(&bdi->usage_cnt));
+}
+
+/**
+ * wb_memcg_offline - kill all wb's associated with a memcg being offlined
+ * @memcg: memcg being offlined
+ *
+ * Also prevents creation of any new wb's associated with @memcg.
*/
-#define INIT_BW (100 << (20 - PAGE_SHIFT))
+void wb_memcg_offline(struct mem_cgroup *memcg)
+{
+ LIST_HEAD(to_destroy);
+ struct list_head *memcg_cgwb_list = mem_cgroup_cgwb_list(memcg);
+ struct bdi_writeback *wb, *next;
+
+ spin_lock_irq(&cgwb_lock);
+ list_for_each_entry_safe(wb, next, memcg_cgwb_list, memcg_node)
+ cgwb_kill(wb);
+ memcg_cgwb_list->next = NULL; /* prevent new wb's */
+ spin_unlock_irq(&cgwb_lock);
+}
+
+/**
+ * wb_blkcg_offline - kill all wb's associated with a blkcg being offlined
+ * @blkcg: blkcg being offlined
+ *
+ * Also prevents creation of any new wb's associated with @blkcg.
+ */
+void wb_blkcg_offline(struct blkcg *blkcg)
+{
+ LIST_HEAD(to_destroy);
+ struct bdi_writeback *wb, *next;
+
+ spin_lock_irq(&cgwb_lock);
+ list_for_each_entry_safe(wb, next, &blkcg->cgwb_list, blkcg_node)
+ cgwb_kill(wb);
+ blkcg->cgwb_list.next = NULL; /* prevent new wb's */
+ spin_unlock_irq(&cgwb_lock);
+}
+
+#else /* CONFIG_CGROUP_WRITEBACK */
+
+static int cgwb_bdi_init(struct backing_dev_info *bdi)
+{
+ int err;
+
+ bdi->wb_congested = kzalloc(sizeof(*bdi->wb_congested), GFP_KERNEL);
+ if (!bdi->wb_congested)
+ return -ENOMEM;
+
+ err = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL);
+ if (err) {
+ kfree(bdi->wb_congested);
+ return err;
+ }
+ return 0;
+}
+
+static void cgwb_bdi_destroy(struct backing_dev_info *bdi) { }
+
+#endif /* CONFIG_CGROUP_WRITEBACK */
int bdi_init(struct backing_dev_info *bdi)
{
- int i, err;
+ int ret;
bdi->dev = NULL;
bdi->min_ratio = 0;
bdi->max_ratio = 100;
bdi->max_prop_frac = FPROP_FRAC_BASE;
- spin_lock_init(&bdi->wb_lock);
INIT_LIST_HEAD(&bdi->bdi_list);
- INIT_LIST_HEAD(&bdi->work_list);
+ INIT_LIST_HEAD(&bdi->wb_list);
+ init_waitqueue_head(&bdi->wb_waitq);
- bdi_wb_init(&bdi->wb, bdi);
+ ret = cgwb_bdi_init(bdi);
- for (i = 0; i < NR_BDI_STAT_ITEMS; i++) {
- err = percpu_counter_init(&bdi->bdi_stat[i], 0, GFP_KERNEL);
- if (err)
- goto err;
- }
+ list_add_tail_rcu(&bdi->wb.bdi_node, &bdi->wb_list);
+
+ return ret;
+}
+EXPORT_SYMBOL(bdi_init);
- bdi->dirty_exceeded = 0;
+int bdi_register(struct backing_dev_info *bdi, struct device *parent,
+ const char *fmt, ...)
+{
+ va_list args;
+ struct device *dev;
+
+ if (bdi->dev) /* The driver needs to use separate queues per device */
+ return 0;
- bdi->bw_time_stamp = jiffies;
- bdi->written_stamp = 0;
+ va_start(args, fmt);
+ dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args);
+ va_end(args);
+ if (IS_ERR(dev))
+ return PTR_ERR(dev);
- bdi->balanced_dirty_ratelimit = INIT_BW;
- bdi->dirty_ratelimit = INIT_BW;
- bdi->write_bandwidth = INIT_BW;
- bdi->avg_write_bandwidth = INIT_BW;
+ bdi->dev = dev;
- err = fprop_local_init_percpu(&bdi->completions, GFP_KERNEL);
+ bdi_debug_register(bdi, dev_name(dev));
+ set_bit(WB_registered, &bdi->wb.state);
- if (err) {
-err:
- while (i--)
- percpu_counter_destroy(&bdi->bdi_stat[i]);
- }
+ spin_lock_bh(&bdi_lock);
+ list_add_tail_rcu(&bdi->bdi_list, &bdi_list);
+ spin_unlock_bh(&bdi_lock);
- return err;
+ trace_writeback_bdi_register(bdi);
+ return 0;
}
-EXPORT_SYMBOL(bdi_init);
+EXPORT_SYMBOL(bdi_register);
-void bdi_destroy(struct backing_dev_info *bdi)
+int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev)
{
- int i;
+ return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev));
+}
+EXPORT_SYMBOL(bdi_register_dev);
- bdi_wb_shutdown(bdi);
- bdi_set_min_ratio(bdi, 0);
+/*
+ * Remove bdi from bdi_list, and ensure that it is no longer visible
+ */
+static void bdi_remove_from_list(struct backing_dev_info *bdi)
+{
+ spin_lock_bh(&bdi_lock);
+ list_del_rcu(&bdi->bdi_list);
+ spin_unlock_bh(&bdi_lock);
- WARN_ON(!list_empty(&bdi->work_list));
- WARN_ON(delayed_work_pending(&bdi->wb.dwork));
+ synchronize_rcu_expedited();
+}
+
+void bdi_unregister(struct backing_dev_info *bdi)
+{
+ /* make sure nobody finds us on the bdi_list anymore */
+ bdi_remove_from_list(bdi);
+ wb_shutdown(&bdi->wb);
+ cgwb_bdi_destroy(bdi);
if (bdi->dev) {
bdi_debug_unregister(bdi);
device_unregister(bdi->dev);
bdi->dev = NULL;
}
+}
- for (i = 0; i < NR_BDI_STAT_ITEMS; i++)
- percpu_counter_destroy(&bdi->bdi_stat[i]);
- fprop_local_destroy_percpu(&bdi->completions);
+void bdi_exit(struct backing_dev_info *bdi)
+{
+ WARN_ON_ONCE(bdi->dev);
+ wb_exit(&bdi->wb);
+}
+
+void bdi_destroy(struct backing_dev_info *bdi)
+{
+ bdi_unregister(bdi);
+ bdi_exit(bdi);
}
EXPORT_SYMBOL(bdi_destroy);
__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),
__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])
};
-static atomic_t nr_bdi_congested[2];
+static atomic_t nr_wb_congested[2];
-void clear_bdi_congested(struct backing_dev_info *bdi, int sync)
+void clear_wb_congested(struct bdi_writeback_congested *congested, int sync)
{
- enum bdi_state bit;
wait_queue_head_t *wqh = &congestion_wqh[sync];
+ enum wb_state bit;
- bit = sync ? BDI_sync_congested : BDI_async_congested;
- if (test_and_clear_bit(bit, &bdi->state))
- atomic_dec(&nr_bdi_congested[sync]);
+ bit = sync ? WB_sync_congested : WB_async_congested;
+ if (test_and_clear_bit(bit, &congested->state))
+ atomic_dec(&nr_wb_congested[sync]);
smp_mb__after_atomic();
if (waitqueue_active(wqh))
wake_up(wqh);
}
-EXPORT_SYMBOL(clear_bdi_congested);
+EXPORT_SYMBOL(clear_wb_congested);
-void set_bdi_congested(struct backing_dev_info *bdi, int sync)
+void set_wb_congested(struct bdi_writeback_congested *congested, int sync)
{
- enum bdi_state bit;
+ enum wb_state bit;
- bit = sync ? BDI_sync_congested : BDI_async_congested;
- if (!test_and_set_bit(bit, &bdi->state))
- atomic_inc(&nr_bdi_congested[sync]);
+ bit = sync ? WB_sync_congested : WB_async_congested;
+ if (!test_and_set_bit(bit, &congested->state))
+ atomic_inc(&nr_wb_congested[sync]);
}
-EXPORT_SYMBOL(set_bdi_congested);
+EXPORT_SYMBOL(set_wb_congested);
/**
* congestion_wait - wait for a backing_dev to become uncongested
* jiffies for either a BDI to exit congestion of the given @sync queue
* or a write to complete.
*
- * In the absence of zone congestion, cond_resched() is called to yield
- * the processor if necessary but otherwise does not sleep.
+ * In the absence of zone congestion, a short sleep or a cond_resched is
+ * performed to yield the processor and to allow other subsystems to make
+ * a forward progress.
*
* The return value is 0 if the sleep is for the full timeout. Otherwise,
* it is the number of jiffies that were still remaining when the function
* encountered in the current zone, yield if necessary instead
* of sleeping on the congestion queue
*/
- if (atomic_read(&nr_bdi_congested[sync]) == 0 ||
+ if (atomic_read(&nr_wb_congested[sync]) == 0 ||
!test_bit(ZONE_CONGESTED, &zone->flags)) {
- cond_resched();
+
+ /*
+ * Memory allocation/reclaim might be called from a WQ
+ * context and the current implementation of the WQ
+ * concurrency control doesn't recognize that a particular
+ * WQ is congested if the worker thread is looping without
+ * ever sleeping. Therefore we have to do a short sleep
+ * here rather than calling cond_resched().
+ */
+ if (current->flags & PF_WQ_WORKER)
+ schedule_timeout_uninterruptible(1);
+ else
+ cond_resched();
/* In case we scheduled, work out time remaining */
ret = timeout - (jiffies - start);
Code Review / kvmfornfv.git / blobdiff