This is a note to let you know that I've just added the patch titled
mm/damon/lru_sort: fix quota status loss due to online tunings
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-damon-lru_sort-fix-quota-status-loss-due-to-online-tunings.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 13d0599ab3b2ff17f798353f24bcbef1659d3cfc Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj@xxxxxxxxxx>
Date: Fri, 16 Feb 2024 11:40:25 -0800
Subject: mm/damon/lru_sort: fix quota status loss due to online tunings
From: SeongJae Park <sj@xxxxxxxxxx>
commit 13d0599ab3b2ff17f798353f24bcbef1659d3cfc upstream.
For online parameters change, DAMON_LRU_SORT creates new schemes based on
latest values of the parameters and replaces the old schemes with the new
one. When creating it, the internal status of the quotas of the old
schemes is not preserved. As a result, charging of the quota starts from
zero after the online tuning. The data that collected to estimate the
throughput of the scheme's action is also reset, and therefore the
estimation should start from the scratch again. Because the throughput
estimation is being used to convert the time quota to the effective size
quota, this could result in temporal time quota inaccuracy. It would be
recovered over time, though. In short, the quota accuracy could be
temporarily degraded after online parameters update.
Fix the problem by checking the case and copying the internal fields for
the status.
Link: https://lkml.kernel.org/r/20240216194025.9207-3-sj@xxxxxxxxxx
Fixes: 40e983cca927 ("mm/damon: introduce DAMON-based LRU-lists Sorting")
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [6.0+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/damon/lru_sort.c | 43 ++++++++++++++++++++++++++++++++++++-------
1 file changed, 36 insertions(+), 7 deletions(-)
--- a/mm/damon/lru_sort.c
+++ b/mm/damon/lru_sort.c
@@ -183,9 +183,21 @@ static struct damos *damon_lru_sort_new_
return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_DEPRIO);
}
+static void damon_lru_sort_copy_quota_status(struct damos_quota *dst,
+ struct damos_quota *src)
+{
+ dst->total_charged_sz = src->total_charged_sz;
+ dst->total_charged_ns = src->total_charged_ns;
+ dst->charged_sz = src->charged_sz;
+ dst->charged_from = src->charged_from;
+ dst->charge_target_from = src->charge_target_from;
+ dst->charge_addr_from = src->charge_addr_from;
+}
+
static int damon_lru_sort_apply_parameters(void)
{
- struct damos *scheme;
+ struct damos *scheme, *hot_scheme, *cold_scheme;
+ struct damos *old_hot_scheme = NULL, *old_cold_scheme = NULL;
unsigned int hot_thres, cold_thres;
int err = 0;
@@ -193,18 +205,35 @@ static int damon_lru_sort_apply_paramete
if (err)
return err;
+ damon_for_each_scheme(scheme, ctx) {
+ if (!old_hot_scheme) {
+ old_hot_scheme = scheme;
+ continue;
+ }
+ old_cold_scheme = scheme;
+ }
+
hot_thres = damon_max_nr_accesses(&damon_lru_sort_mon_attrs) *
hot_thres_access_freq / 1000;
- scheme = damon_lru_sort_new_hot_scheme(hot_thres);
- if (!scheme)
+ hot_scheme = damon_lru_sort_new_hot_scheme(hot_thres);
+ if (!hot_scheme)
return -ENOMEM;
- damon_set_schemes(ctx, &scheme, 1);
+ if (old_hot_scheme)
+ damon_lru_sort_copy_quota_status(&hot_scheme->quota,
+ &old_hot_scheme->quota);
cold_thres = cold_min_age / damon_lru_sort_mon_attrs.aggr_interval;
- scheme = damon_lru_sort_new_cold_scheme(cold_thres);
- if (!scheme)
+ cold_scheme = damon_lru_sort_new_cold_scheme(cold_thres);
+ if (!cold_scheme) {
+ damon_destroy_scheme(hot_scheme);
return -ENOMEM;
- damon_add_scheme(ctx, scheme);
+ }
+ if (old_cold_scheme)
+ damon_lru_sort_copy_quota_status(&cold_scheme->quota,
+ &old_cold_scheme->quota);
+
+ damon_set_schemes(ctx, &hot_scheme, 1);
+ damon_add_scheme(ctx, cold_scheme);
return damon_set_region_biggest_system_ram_default(target,
&monitor_region_start,
Patches currently in stable-queue which might be from sj@xxxxxxxxxx are
queue-6.6/mm-damon-lru_sort-fix-quota-status-loss-due-to-online-tunings.patch
queue-6.6/mm-damon-reclaim-fix-quota-stauts-loss-due-to-online-tunings.patch
queue-6.6/mm-swap-fix-race-when-skipping-swapcache.patch
