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 _
