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| author | Nikolay Borisov <nborisov@suse.com> | 2017-07-12 14:37:51 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-12 16:26:05 -0700 |
| commit | 3e8f399da490e6ac20a3cfd6aa404c9aa961a9a2 (patch) | |
| tree | 1e7ef3c2a6de595ad3d8d7f121b509f2ffeda371 /mm/page-writeback.c | |
| parent | c945dccc80856107f109c36a7d0e29a371b5d1b5 (diff) | |
| download | lwn-3e8f399da490e6ac20a3cfd6aa404c9aa961a9a2.tar.gz lwn-3e8f399da490e6ac20a3cfd6aa404c9aa961a9a2.zip | |
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 <nborisov@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Josef Bacik <jbacik@fb.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page-writeback.c')
| -rw-r--r-- | mm/page-writeback.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 0b60cc7ddac2..96e93b214d31 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -601,7 +601,7 @@ static inline void __wb_writeout_inc(struct bdi_writeback *wb) { struct wb_domain *cgdom; - __inc_wb_stat(wb, WB_WRITTEN); + inc_wb_stat(wb, WB_WRITTEN); wb_domain_writeout_inc(&global_wb_domain, &wb->completions, wb->bdi->max_prop_frac); @@ -2435,8 +2435,8 @@ void account_page_dirtied(struct page *page, struct address_space *mapping) __inc_lruvec_page_state(page, NR_FILE_DIRTY); __inc_zone_page_state(page, NR_ZONE_WRITE_PENDING); __inc_node_page_state(page, NR_DIRTIED); - __inc_wb_stat(wb, WB_RECLAIMABLE); - __inc_wb_stat(wb, WB_DIRTIED); + inc_wb_stat(wb, WB_RECLAIMABLE); + inc_wb_stat(wb, WB_DIRTIED); task_io_account_write(PAGE_SIZE); current->nr_dirtied++; this_cpu_inc(bdp_ratelimits); @@ -2741,7 +2741,7 @@ int test_clear_page_writeback(struct page *page) if (bdi_cap_account_writeback(bdi)) { struct bdi_writeback *wb = inode_to_wb(inode); - __dec_wb_stat(wb, WB_WRITEBACK); + dec_wb_stat(wb, WB_WRITEBACK); __wb_writeout_inc(wb); } } @@ -2786,7 +2786,7 @@ int __test_set_page_writeback(struct page *page, bool keep_write) page_index(page), PAGECACHE_TAG_WRITEBACK); if (bdi_cap_account_writeback(bdi)) - __inc_wb_stat(inode_to_wb(inode), WB_WRITEBACK); + inc_wb_stat(inode_to_wb(inode), WB_WRITEBACK); /* * We can come through here when swapping anonymous |