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From: Tejun Heo <tj@kernel.org>
To: axboe@kernel.dk
Cc: linux-kernel@vger.kernel.org, jack@suse.cz, hch@infradead.org,
	hannes@cmpxchg.org, linux-fsdevel@vger.kernel.org,
	vgoyal@redhat.com, lizefan@huawei.com, cgroups@vger.kernel.org,
	linux-mm@kvack.org, mhocko@suse.cz, clm@fb.com,
	fengguang.wu@intel.com, david@fromorbit.com, gthelen@google.com,
	Tejun Heo <tj@kernel.org>
Subject: [PATCH 34/48] writeback: implement bdi_for_each_wb()
Date: Mon, 23 Mar 2015 00:54:45 -0400
Message-ID: <1427086499-15657-35-git-send-email-tj@kernel.org> (raw)
In-Reply-To: <1427086499-15657-1-git-send-email-tj@kernel.org>

This will be used to implement bdi-wide operations which should be
distributed across all its cgroup bdi_writebacks.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
---
 include/linux/backing-dev.h | 63 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 433b308..9dc4eea 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -384,6 +384,61 @@ static inline struct bdi_writeback *inode_to_wb(struct inode *inode)
 	return inode->i_wb;
 }
 
+struct wb_iter {
+	int			start_blkcg_id;
+	struct radix_tree_iter	tree_iter;
+	void			**slot;
+};
+
+static inline struct bdi_writeback *__wb_iter_next(struct wb_iter *iter,
+						   struct backing_dev_info *bdi)
+{
+	struct radix_tree_iter *titer = &iter->tree_iter;
+
+	WARN_ON_ONCE(!rcu_read_lock_held());
+
+	if (iter->start_blkcg_id >= 0) {
+		iter->slot = radix_tree_iter_init(titer, iter->start_blkcg_id);
+		iter->start_blkcg_id = -1;
+	} else {
+		iter->slot = radix_tree_next_slot(iter->slot, titer, 0);
+	}
+
+	if (!iter->slot)
+		iter->slot = radix_tree_next_chunk(&bdi->cgwb_tree, titer, 0);
+	if (iter->slot)
+		return *iter->slot;
+	return NULL;
+}
+
+static inline struct bdi_writeback *__wb_iter_init(struct wb_iter *iter,
+						   struct backing_dev_info *bdi,
+						   int start_blkcg_id)
+{
+	iter->start_blkcg_id = start_blkcg_id;
+
+	if (start_blkcg_id)
+		return __wb_iter_next(iter, bdi);
+	else
+		return &bdi->wb;
+}
+
+/**
+ * bdi_for_each_wb - walk all wb's of a bdi in ascending blkcg ID order
+ * @wb_cur: cursor struct bdi_writeback pointer
+ * @bdi: bdi to walk wb's of
+ * @iter: pointer to struct wb_iter to be used as iteration buffer
+ * @start_blkcg_id: blkcg ID to start iteration from
+ *
+ * Iterate @wb_cur through the wb's (bdi_writeback's) of @bdi in ascending
+ * blkcg ID order starting from @start_blkcg_id.  @iter is struct wb_iter
+ * to be used as temp storage during iteration.  rcu_read_lock() must be
+ * held throughout iteration.
+ */
+#define bdi_for_each_wb(wb_cur, bdi, iter, start_blkcg_id)		\
+	for ((wb_cur) = __wb_iter_init(iter, bdi, start_blkcg_id);	\
+	     (wb_cur); (wb_cur) = __wb_iter_next(iter, bdi))
+
 #else	/* CONFIG_CGROUP_WRITEBACK */
 
 static inline bool inode_cgwb_enabled(struct inode *inode)
@@ -446,6 +501,14 @@ static inline void wb_blkcg_offline(struct blkcg *blkcg)
 {
 }
 
+struct wb_iter {
+	int		next_id;
+};
+
+#define bdi_for_each_wb(wb_cur, bdi, iter, start_blkcg_id)		\
+	for ((iter)->next_id = (start_blkcg_id);			\
+	     ({	(wb_cur) = !(iter)->next_id++ ? &(bdi)->wb : NULL; }); )
+
 static inline int mapping_congested(struct address_space *mapping,
 				    struct task_struct *task, int cong_bits)
 {
-- 
2.1.0


  parent reply index

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-23  4:54 [PATCHSET 1/3 v2 block/for-4.1/core] writeback: cgroup writeback support Tejun Heo
2015-03-23  4:54 ` [PATCH 01/48] memcg: add per cgroup dirty page accounting Tejun Heo
2015-03-23  4:54 ` [PATCH 02/48] blkcg: move block/blk-cgroup.h to include/linux/blk-cgroup.h Tejun Heo
2015-03-23  4:54 ` [PATCH 04/48] memcg: add mem_cgroup_root_css Tejun Heo
2015-03-23  4:54 ` [PATCH 05/48] blkcg: add blkcg_root_css Tejun Heo
2015-03-23  4:54 ` [PATCH 06/48] cgroup, block: implement task_get_css() and use it in bio_associate_current() Tejun Heo
2015-03-23  4:54 ` [PATCH 07/48] blkcg: implement task_get_blkcg_css() Tejun Heo
2015-03-23  4:54 ` [PATCH 08/48] blkcg: implement bio_associate_blkcg() Tejun Heo
2015-03-23  4:54 ` [PATCH 09/48] memcg: implement mem_cgroup_css_from_page() Tejun Heo
2015-03-23  4:54 ` [PATCH 10/48] writeback: move backing_dev_info->state into bdi_writeback Tejun Heo
2015-03-23  4:54 ` [PATCH 11/48] writeback: move backing_dev_info->bdi_stat[] " Tejun Heo
2015-03-23  4:54 ` [PATCH 12/48] writeback: move bandwidth related fields from backing_dev_info " Tejun Heo
2015-03-23  4:54 ` [PATCH 13/48] writeback: s/bdi/wb/ in mm/page-writeback.c Tejun Heo
2015-03-23  4:54 ` [PATCH 14/48] writeback: move backing_dev_info->wb_lock and ->worklist into bdi_writeback Tejun Heo
2015-03-23  4:54 ` [PATCH 15/48] writeback: reorganize mm/backing-dev.c Tejun Heo
2015-03-23  4:54 ` [PATCH 16/48] writeback: separate out include/linux/backing-dev-defs.h Tejun Heo
2015-03-23  4:54 ` [PATCH 17/48] bdi: make inode_to_bdi() inline Tejun Heo
2015-03-23  4:54 ` [PATCH 18/48] writeback: add @gfp to wb_init() Tejun Heo
2015-03-23  4:54 ` [PATCH 19/48] bdi: separate out congested state into a separate struct Tejun Heo
2015-03-23  4:54 ` [PATCH 20/48] writeback: add {CONFIG|BDI_CAP|FS}_CGROUP_WRITEBACK Tejun Heo
2015-03-23  4:54 ` [PATCH 21/48] writeback: make backing_dev_info host cgroup-specific bdi_writebacks Tejun Heo
2015-03-27 21:06   ` Vivek Goyal
2015-03-27 21:41     ` Tejun Heo
2015-03-23  4:54 ` [PATCH 22/48] writeback, blkcg: associate each blkcg_gq with the corresponding bdi_writeback_congested Tejun Heo
2015-03-23  4:54 ` [PATCH 24/48] writeback: let balance_dirty_pages() work on the matching cgroup bdi_writeback Tejun Heo
2015-03-23  4:54 ` [PATCH 25/48] writeback: make congestion functions per bdi_writeback Tejun Heo
2015-03-23  4:54 ` [PATCH 26/48] writeback, blkcg: restructure blk_{set|clear}_queue_congested() Tejun Heo
2015-03-23  4:54 ` [PATCH 28/48] writeback: implement and use mapping_congested() Tejun Heo
     [not found]   ` <1427086499-15657-29-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-03-27 18:06     ` Vivek Goyal
2015-03-27 21:46       ` Tejun Heo
2015-03-23  4:54 ` [PATCH 29/48] writeback: implement WB_has_dirty_io wb_state flag Tejun Heo
2015-03-23  4:54 ` [PATCH 30/48] writeback: implement backing_dev_info->tot_write_bandwidth Tejun Heo
2015-03-23  4:54 ` [PATCH 31/48] writeback: make bdi_has_dirty_io() take multiple bdi_writeback's into account Tejun Heo
2015-03-23  4:54 ` [PATCH 32/48] writeback: don't issue wb_writeback_work if clean Tejun Heo
2015-03-23  4:54 ` [PATCH 33/48] writeback: make bdi->min/max_ratio handling cgroup writeback aware Tejun Heo
2015-03-23  4:54 ` Tejun Heo [this message]
2015-03-23  4:54 ` [PATCH 35/48] writeback: remove bdi_start_writeback() Tejun Heo
2015-03-23  4:54 ` [PATCH 36/48] writeback: make laptop_mode_timer_fn() handle multiple bdi_writeback's Tejun Heo
2015-03-23  4:54 ` [PATCH 37/48] writeback: make writeback_in_progress() take bdi_writeback instead of backing_dev_info Tejun Heo
2015-03-23  4:54 ` [PATCH 38/48] writeback: make bdi_start_background_writeback() " Tejun Heo
2015-03-23  4:54 ` [PATCH 39/48] writeback: make wakeup_flusher_threads() handle multiple bdi_writeback's Tejun Heo
2015-03-23  4:54 ` [PATCH 40/48] writeback: add wb_writeback_work->auto_free Tejun Heo
2015-03-23  4:54 ` [PATCH 41/48] writeback: implement bdi_wait_for_completion() Tejun Heo
2015-03-23  4:54 ` [PATCH 42/48] writeback: implement wb_wait_for_single_work() Tejun Heo
2015-03-23  4:54 ` [PATCH 44/48] writeback: make writeback initiation functions handle multiple bdi_writeback's Tejun Heo
2015-03-23  4:54 ` [PATCH 45/48] writeback: dirty inodes against their matching cgroup bdi_writeback's Tejun Heo
2015-03-23  4:54 ` [PATCH 46/48] buffer, writeback: make __block_write_full_page() honor cgroup writeback Tejun Heo
2015-03-23  4:54 ` [PATCH 47/48] mpage: make __mpage_writepage() " Tejun Heo
2015-03-23  4:54 ` [PATCH 48/48] ext2: enable cgroup writeback support Tejun Heo
     [not found] ` <1427086499-15657-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-03-23  4:54   ` [PATCH 03/48] update !CONFIG_BLK_CGROUP dummies in include/linux/blk-cgroup.h Tejun Heo
2015-03-23  4:54   ` [PATCH 23/48] writeback: attribute stats to the matching per-cgroup bdi_writeback Tejun Heo
2015-03-23  4:54   ` [PATCH 27/48] writeback, blkcg: propagate non-root blkcg congestion state Tejun Heo
2015-03-23  4:54   ` [PATCH 43/48] writeback: restructure try_writeback_inodes_sb[_nr]() Tejun Heo
2015-03-25 15:40   ` [PATCHSET 1/3 v2 block/for-4.1/core] writeback: cgroup writeback support Vivek Goyal
     [not found]     ` <20150325154022.GC29728-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-03-25 16:01       ` Tejun Heo
2015-03-31 15:26 ` Tejun Heo

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