linux-kernel - [PATCH] mm: page-writeback: Kill get_writeback

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Message-ID: <20210508125026.56600-1-wangkefeng.wang@huawei.com>
Date:   Sat, 8 May 2021 20:50:26 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     Andrew Morton <akpm@...ux-foundation.org>, <linux-mm@...ck.org>
CC:     <linux-kernel@...r.kernel.org>,
        Kefeng Wang <wangkefeng.wang@...wei.com>
Subject: [PATCH] mm: page-writeback: Kill get_writeback_state() comments

The get_writeback_state() has gone since 2006, kill related comments.

Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
---
 mm/page-writeback.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 0062d5c57d41..1bbe185a6524 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1869,10 +1869,9 @@ DEFINE_PER_CPU(int, dirty_throttle_leaks) = 0;
  * 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
-- 
2.26.2