[PATCH 15/19] writeback: update wb_over_bg_thresh() to use wb_domain aware operations
From: Tejun Heo <tj@kernel.org>
Date: 2015-05-22 22:23:32
Also in:
linux-fsdevel, linux-mm, lkml
Subsystem:
memory management, page cache, the rest · Maintainers:
Andrew Morton, Matthew Wilcox, Linus Torvalds
wb_over_bg_thresh() currently uses global_dirty_limits() and wb_dirty_limit() both of which are wrappers around operations which take dirty_throttle_control. For cgroup writeback support, the function will be updated to also consider memcg wb_domains which requires the context information carried in dirty_throttle_control. This patch updates wb_over_bg_thresh() so that it uses the underlying wb_domain aware operations directly and builds the global dirty_throttle_control in the process. This patch 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 <redacted> Cc: Greg Thelen <redacted> --- mm/page-writeback.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 9d9a896..a7ba5ce 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c@@ -1749,15 +1749,22 @@ EXPORT_SYMBOL(balance_dirty_pages_ratelimited); */ bool wb_over_bg_thresh(struct bdi_writeback *wb) { - unsigned long background_thresh, dirty_thresh; + struct dirty_throttle_control gdtc_stor = { GDTC_INIT(wb) }; + struct dirty_throttle_control * const gdtc = &gdtc_stor; - global_dirty_limits(&background_thresh, &dirty_thresh); + /* + * Similar to balance_dirty_pages() but ignores pages being written + * as we're trying to decide whether to put more under writeback. + */ + gdtc->avail = global_dirtyable_memory(); + gdtc->dirty = global_page_state(NR_FILE_DIRTY) + + global_page_state(NR_UNSTABLE_NFS); + domain_dirty_limits(gdtc); - if (global_page_state(NR_FILE_DIRTY) + - global_page_state(NR_UNSTABLE_NFS) > background_thresh) + if (gdtc->dirty > gdtc->bg_thresh) return true; - if (wb_stat(wb, WB_RECLAIMABLE) > wb_calc_thresh(wb, background_thresh)) + if (wb_stat(wb, WB_RECLAIMABLE) > __wb_calc_thresh(gdtc)) return true; return false;
--
2.4.0
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