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authorSeongJae Park <sj@kernel.org>2021-11-05 23:47:16 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-06 23:30:45 +0300
commit2b8a248d5873343aa16f6c5ede30517693995f13 (patch)
tree2f752463155c604c8cd52241654fb80c8aa0b040 /mm
parent57223ac295845b1d72ec1bd02b5fab992b77a021 (diff)
downloadlinux-2b8a248d5873343aa16f6c5ede30517693995f13.tar.xz
mm/damon/schemes: implement size quota for schemes application speed control
There could be arbitrarily large memory regions fulfilling the target data access pattern of a DAMON-based operation scheme. In the case, applying the action of the scheme could incur too high overhead. To provide an intuitive way for avoiding it, this implements a feature called size quota. If the quota is set, DAMON tries to apply the action only up to the given amount of memory regions within a given time window. Link: https://lkml.kernel.org/r/20211019150731.16699-3-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Amit Shah <amit@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: David Woodhouse <dwmw@amazon.com> Cc: Greg Thelen <gthelen@google.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Leonard Foerster <foersleo@amazon.de> Cc: Marco Elver <elver@google.com> Cc: Markus Boehme <markubo@amazon.de> Cc: Shakeel Butt <shakeelb@google.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/damon/core.c60
-rw-r--r--mm/damon/dbgfs.c4
2 files changed, 55 insertions, 9 deletions
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 2f6785737902..cce14a0d5c72 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -89,7 +89,7 @@ struct damos *damon_new_scheme(
unsigned long min_sz_region, unsigned long max_sz_region,
unsigned int min_nr_accesses, unsigned int max_nr_accesses,
unsigned int min_age_region, unsigned int max_age_region,
- enum damos_action action)
+ enum damos_action action, struct damos_quota *quota)
{
struct damos *scheme;
@@ -107,6 +107,11 @@ struct damos *damon_new_scheme(
scheme->stat_sz = 0;
INIT_LIST_HEAD(&scheme->list);
+ scheme->quota.sz = quota->sz;
+ scheme->quota.reset_interval = quota->reset_interval;
+ scheme->quota.charged_sz = 0;
+ scheme->quota.charged_from = 0;
+
return scheme;
}
@@ -530,15 +535,25 @@ static void kdamond_reset_aggregated(struct damon_ctx *c)
}
}
+static void damon_split_region_at(struct damon_ctx *ctx,
+ struct damon_target *t, struct damon_region *r,
+ unsigned long sz_r);
+
static void damon_do_apply_schemes(struct damon_ctx *c,
struct damon_target *t,
struct damon_region *r)
{
struct damos *s;
- unsigned long sz;
damon_for_each_scheme(s, c) {
- sz = r->ar.end - r->ar.start;
+ struct damos_quota *quota = &s->quota;
+ unsigned long sz = r->ar.end - r->ar.start;
+
+ /* Check the quota */
+ if (quota->sz && quota->charged_sz >= quota->sz)
+ continue;
+
+ /* Check the target regions condition */
if (sz < s->min_sz_region || s->max_sz_region < sz)
continue;
if (r->nr_accesses < s->min_nr_accesses ||
@@ -546,22 +561,51 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
continue;
if (r->age < s->min_age_region || s->max_age_region < r->age)
continue;
- s->stat_count++;
- s->stat_sz += sz;
- if (c->primitive.apply_scheme)
+
+ /* Apply the scheme */
+ if (c->primitive.apply_scheme) {
+ if (quota->sz && quota->charged_sz + sz > quota->sz) {
+ sz = ALIGN_DOWN(quota->sz - quota->charged_sz,
+ DAMON_MIN_REGION);
+ if (!sz)
+ goto update_stat;
+ damon_split_region_at(c, t, r, sz);
+ }
c->primitive.apply_scheme(c, t, r, s);
+ quota->charged_sz += sz;
+ }
if (s->action != DAMOS_STAT)
r->age = 0;
+
+update_stat:
+ s->stat_count++;
+ s->stat_sz += sz;
}
}
static void kdamond_apply_schemes(struct damon_ctx *c)
{
struct damon_target *t;
- struct damon_region *r;
+ struct damon_region *r, *next_r;
+ struct damos *s;
+
+ damon_for_each_scheme(s, c) {
+ struct damos_quota *quota = &s->quota;
+
+ if (!quota->sz)
+ continue;
+
+ /* New charge window starts */
+ if (time_after_eq(jiffies, quota->charged_from +
+ msecs_to_jiffies(
+ quota->reset_interval))) {
+ quota->charged_from = jiffies;
+ quota->charged_sz = 0;
+ }
+ }
damon_for_each_target(t, c) {
- damon_for_each_region(r, t)
+ damon_for_each_region_safe(r, next_r, t)
damon_do_apply_schemes(c, t, r);
}
}
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
index c90988a20fa4..a04bd50cc4c4 100644
--- a/mm/damon/dbgfs.c
+++ b/mm/damon/dbgfs.c
@@ -188,6 +188,8 @@ static struct damos **str_to_schemes(const char *str, ssize_t len,
*nr_schemes = 0;
while (pos < len && *nr_schemes < max_nr_schemes) {
+ struct damos_quota quota = {};
+
ret = sscanf(&str[pos], "%lu %lu %u %u %u %u %u%n",
&min_sz, &max_sz, &min_nr_a, &max_nr_a,
&min_age, &max_age, &action, &parsed);
@@ -200,7 +202,7 @@ static struct damos **str_to_schemes(const char *str, ssize_t len,
pos += parsed;
scheme = damon_new_scheme(min_sz, max_sz, min_nr_a, max_nr_a,
- min_age, max_age, action);
+ min_age, max_age, action, &quota);
if (!scheme)
goto fail;