[080/128] mm/memcg: move penalty delay clamping out of calculate_high_delay()

Commit Message

Andrew Morton June 2, 2020, 8:14 p.m. UTC

From: Jakub Kicinski <[e-mail]>
Subject: mm/memcg: move penalty delay clamping out of calculate_high_delay()

We will want to call calculate_high_delay() twice - once for memory and
once for swap, and we should apply the clamp value to sum of the
penalties.  Clamping has to be applied outside of calculate_high_delay().

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>
Reviewed-by: Shakeel Butt <[e-mail]>
Acked-by: Johannes Weiner <[e-mail]>
Cc: Chris Down <[e-mail]>
Cc: Hugh Dickins <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: Tejun Heo <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/memcontrol.c |   16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

Patch

--- a/mm/memcontrol.c~mm-move-penalty-delay-clamping-out-of-calculate_high_delay
+++ a/mm/memcontrol.c
@@ -2386,14 +2386,7 @@  static unsigned long calculate_high_dela
 	 * MEMCG_CHARGE_BATCH pages is nominal, so work out how much smaller or
 	 * larger the current charge patch is than that.
 	 */
-	penalty_jiffies = penalty_jiffies * nr_pages / MEMCG_CHARGE_BATCH;
-
-	/*
-	 * Clamp the max delay per usermode return so as to still keep the
-	 * application moving forwards and also permit diagnostics, albeit
-	 * extremely slowly.
-	 */
-	return min(penalty_jiffies, MEMCG_MAX_HIGH_DELAY_JIFFIES);
+	return penalty_jiffies * nr_pages / MEMCG_CHARGE_BATCH;
 }
 
 /*
@@ -2422,6 +2415,13 @@  void mem_cgroup_handle_over_high(void)
 					       mem_find_max_overage(memcg));
 
 	/*
+	 * Clamp the max delay per usermode return so as to still keep the
+	 * application moving forwards and also permit diagnostics, albeit
+	 * extremely slowly.
+	 */
+	penalty_jiffies = min(penalty_jiffies, MEMCG_MAX_HIGH_DELAY_JIFFIES);
+
+	/*
 	 * Don't sleep if the amount of jiffies this memcg owes us is so low
 	 * that it's not even worth doing, in an attempt to be nice to those who
 	 * go only a small amount over their memory.high value and maybe haven't