From 3e8f399da490e6ac20a3cfd6aa404c9aa961a9a2 Mon Sep 17 00:00:00 2001 From: Nikolay Borisov Date: Wed, 12 Jul 2017 14:37:51 -0700 Subject: writeback: rework wb_[dec|inc]_stat family of functions Currently the writeback statistics code uses a percpu counters to hold various statistics. Furthermore we have 2 families of functions - those which disable local irq and those which doesn't and whose names begin with double underscore. However, they both end up calling __add_wb_stats which in turn calls percpu_counter_add_batch which is already irq-safe. Exploiting this fact allows to eliminated the __wb_* functions since they don't add any further protection than we already have. Furthermore, refactor the wb_* function to call __add_wb_stat directly without the irq-disabling dance. This will likely result in better runtime of code which deals with modifying the stat counters. While at it also document why percpu_counter_add_batch is in fact preempt and irq-safe since at least 3 people got confused. Link: http://lkml.kernel.org/r/1498029937-27293-1-git-send-email-nborisov@suse.com Signed-off-by: Nikolay Borisov Acked-by: Tejun Heo Reviewed-by: Jan Kara Cc: Josef Bacik Cc: Mel Gorman Cc: Jeff Layton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/fs-writeback.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'fs/fs-writeback.c') diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 8b426f83909f..245c430a2e41 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -380,8 +380,8 @@ static void inode_switch_wbs_work_fn(struct work_struct *work) struct page *page = radix_tree_deref_slot_protected(slot, &mapping->tree_lock); if (likely(page) && PageDirty(page)) { - __dec_wb_stat(old_wb, WB_RECLAIMABLE); - __inc_wb_stat(new_wb, WB_RECLAIMABLE); + dec_wb_stat(old_wb, WB_RECLAIMABLE); + inc_wb_stat(new_wb, WB_RECLAIMABLE); } } @@ -391,8 +391,8 @@ static void inode_switch_wbs_work_fn(struct work_struct *work) &mapping->tree_lock); if (likely(page)) { WARN_ON_ONCE(!PageWriteback(page)); - __dec_wb_stat(old_wb, WB_WRITEBACK); - __inc_wb_stat(new_wb, WB_WRITEBACK); + dec_wb_stat(old_wb, WB_WRITEBACK); + inc_wb_stat(new_wb, WB_WRITEBACK); } } -- cgit v1.2.3