From aa661bbe1e61ce80ca4ae98804f673ede94b0827 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 18:23:31 -0400 Subject: [PATCH] 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 Cc: Jens Axboe Cc: Jan Kara Cc: Wu Fengguang Cc: Greg Thelen Signed-off-by: Jens Axboe --- fs/fs-writeback.c | 20 ++------------------ include/linux/writeback.h | 1 + mm/page-writeback.c | 23 +++++++++++++++++++++++ 3 files changed, 26 insertions(+), 18 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 51c8a5b14cdf..da355879ba7c 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 5fdd4e1805e6..b57c2786b5aa 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 c8ac8cea67dc..9d9a896fa7b5 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;