The patch titled
Subject: mm: page-writeback: kill get_writeback_state() comments
has been added to the -mm tree. Its filename is
mm-page-writeback-kill-get_writeback_state-comments.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-page-writeback-kill-get_writeback_state-comments.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-page-writeback-kill-get_writeback_state-comments.patch
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------------------------------------------------------
From: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Subject: mm: page-writeback: kill get_writeback_state() comments
The get_writeback_state() has gone since 2006, kill related comments.
Link: https://lkml.kernel.org/r/20210508125026.56600-1-wangkefeng.wang@xxxxxxxxxx
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page-writeback.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
--- a/mm/page-writeback.c~mm-page-writeback-kill-get_writeback_state-comments
+++ a/mm/page-writeback.c
@@ -1869,10 +1869,9 @@ DEFINE_PER_CPU(int, dirty_throttle_leaks
* which was newly dirtied. The function will periodically check the system's
* dirty state and will initiate writeback if needed.
*
- * On really big machines, get_writeback_state is expensive, so try to avoid
- * calling it too often (ratelimiting). But once we're over the dirty memory
- * limit we decrease the ratelimiting by a lot, to prevent individual processes
- * from overshooting the limit by (ratelimit_pages) each.
+ * Once we're over the dirty memory limit we decrease the ratelimiting
+ * by a lot, to prevent individual processes from overshooting the limit
+ * by (ratelimit_pages) each.
*/
void balance_dirty_pages_ratelimited(struct address_space *mapping)
{
@@ -2045,8 +2044,6 @@ void laptop_sync_completion(void)
/*
* If ratelimit_pages is too high then we can get into dirty-data overload
* if a large number of processes all perform writes at the same time.
- * If it is too low then SMP machines will call the (expensive)
- * get_writeback_state too often.
*
* Here we set ratelimit_pages to a level which ensures that when all CPUs are
* dirtying in parallel, we cannot go more than 3% (1/32) over the dirty memory
_
Patches currently in -mm which might be from wangkefeng.wang@xxxxxxxxxx are
mm-page-writeback-kill-get_writeback_state-comments.patch
