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authorTejun Heo <tj@kernel.org>2015-05-22 18:23:31 -0400
committerJens Axboe <axboe@fb.com>2015-06-02 08:38:13 -0600
commitaa661bbe1e61ce80ca4ae98804f673ede94b0827 (patch)
tree43103c366edc05bb598c042ec7afa31fb9106939
parent9fc3a43e1757ab6de0e8ce83b5d5a83083174e3b (diff)
downloadop-kernel-dev-aa661bbe1e61ce80ca4ae98804f673ede94b0827.zip
op-kernel-dev-aa661bbe1e61ce80ca4ae98804f673ede94b0827.tar.gz
writeback: move over_bground_thresh() to mm/page-writeback.c
and rename it to wb_over_bg_thresh(). The function is closely tied to the dirty throttling mechanism implemented in page-writeback.c. This relocation will allow future updates necessary for cgroup writeback support. While at it, add function comment. This is pure reorganization and doesn't introduce any behavioral 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>
-rw-r--r--fs/fs-writeback.c20
-rw-r--r--include/linux/writeback.h1
-rw-r--r--mm/page-writeback.c23
3 files changed, 26 insertions, 18 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 51c8a5b..da35587 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1071,22 +1071,6 @@ static long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages,
return nr_pages - work.nr_pages;
}
-static bool over_bground_thresh(struct bdi_writeback *wb)
-{
- unsigned long background_thresh, dirty_thresh;
-
- global_dirty_limits(&background_thresh, &dirty_thresh);
-
- if (global_page_state(NR_FILE_DIRTY) +
- global_page_state(NR_UNSTABLE_NFS) > background_thresh)
- return true;
-
- if (wb_stat(wb, WB_RECLAIMABLE) > wb_calc_thresh(wb, background_thresh))
- return true;
-
- return false;
-}
-
/*
* Explicit flushing or periodic writeback of "old" data.
*
@@ -1136,7 +1120,7 @@ static long wb_writeback(struct bdi_writeback *wb,
* For background writeout, stop when we are below the
* background dirty threshold
*/
- if (work->for_background && !over_bground_thresh(wb))
+ if (work->for_background && !wb_over_bg_thresh(wb))
break;
/*
@@ -1227,7 +1211,7 @@ static unsigned long get_nr_dirty_pages(void)
static long wb_check_background_flush(struct bdi_writeback *wb)
{
- if (over_bground_thresh(wb)) {
+ if (wb_over_bg_thresh(wb)) {
struct wb_writeback_work work = {
.nr_pages = LONG_MAX,
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 5fdd4e1..b57c2786 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -207,6 +207,7 @@ unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh);
void wb_update_bandwidth(struct bdi_writeback *wb, unsigned long start_time);
void page_writeback_init(void);
void balance_dirty_pages_ratelimited(struct address_space *mapping);
+bool wb_over_bg_thresh(struct bdi_writeback *wb);
typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
void *data);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index c8ac8ce..9d9a896 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1740,6 +1740,29 @@ void balance_dirty_pages_ratelimited(struct address_space *mapping)
}
EXPORT_SYMBOL(balance_dirty_pages_ratelimited);
+/**
+ * wb_over_bg_thresh - does @wb need to be written back?
+ * @wb: bdi_writeback of interest
+ *
+ * Determines whether background writeback should keep writing @wb or it's
+ * clean enough. Returns %true if writeback should continue.
+ */
+bool wb_over_bg_thresh(struct bdi_writeback *wb)
+{
+ unsigned long background_thresh, dirty_thresh;
+
+ global_dirty_limits(&background_thresh, &dirty_thresh);
+
+ if (global_page_state(NR_FILE_DIRTY) +
+ global_page_state(NR_UNSTABLE_NFS) > background_thresh)
+ return true;
+
+ if (wb_stat(wb, WB_RECLAIMABLE) > wb_calc_thresh(wb, background_thresh))
+ return true;
+
+ return false;
+}
+
void throttle_vm_writeout(gfp_t gfp_mask)
{
unsigned long background_thresh;
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