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authorTejun Heo <tj@kernel.org>2015-05-28 14:50:49 -0400
committerJens Axboe <axboe@fb.com>2015-06-02 08:39:08 -0600
commit21c6321fbb3a3787af07f1bc031d713a707fb69c (patch)
treede5489853b7f0d82adfd74da30d3945aba45e366 /fs/fs-writeback.c
parent97c9341f727105c29478da19f1687b0e0a917256 (diff)
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writeback: relocate wb[_try]_get(), wb_put(), inode_{attach|detach}_wb()
Currently, majority of cgroup writeback support including all the above functions are implemented in include/linux/backing-dev.h and mm/backing-dev.c; however, the portion closely related to writeback logic implemented in include/linux/writeback.h and mm/page-writeback.c will expand to support foreign writeback detection and correction. This patch moves wb[_try]_get() and wb_put() to include/linux/backing-dev-defs.h so that they can be used from writeback.h and inode_{attach|detach}_wb() to writeback.h and page-writeback.c. This is pure reorganization and doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'fs/fs-writeback.c')
-rw-r--r--fs/fs-writeback.c31
1 files changed, 31 insertions, 0 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index da355879ba7c..cf6ccfb01e03 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -27,6 +27,7 @@
#include <linux/backing-dev.h>
#include <linux/tracepoint.h>
#include <linux/device.h>
+#include <linux/memcontrol.h>
#include "internal.h"
/*
@@ -213,6 +214,36 @@ static void wb_wait_for_completion(struct backing_dev_info *bdi,
#ifdef CONFIG_CGROUP_WRITEBACK
+void __inode_attach_wb(struct inode *inode, struct page *page)
+{
+ struct backing_dev_info *bdi = inode_to_bdi(inode);
+ struct bdi_writeback *wb = NULL;
+
+ if (inode_cgwb_enabled(inode)) {
+ struct cgroup_subsys_state *memcg_css;
+
+ if (page) {
+ memcg_css = mem_cgroup_css_from_page(page);
+ wb = wb_get_create(bdi, memcg_css, GFP_ATOMIC);
+ } else {
+ /* must pin memcg_css, see wb_get_create() */
+ memcg_css = task_get_css(current, memory_cgrp_id);
+ wb = wb_get_create(bdi, memcg_css, GFP_ATOMIC);
+ css_put(memcg_css);
+ }
+ }
+
+ if (!wb)
+ wb = &bdi->wb;
+
+ /*
+ * There may be multiple instances of this function racing to
+ * update the same inode. Use cmpxchg() to tell the winner.
+ */
+ if (unlikely(cmpxchg(&inode->i_wb, NULL, wb)))
+ wb_put(wb);
+}
+
/**
* inode_congested - test whether an inode is congested
* @inode: inode to test for congestion