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Message-Id: <20240512193657.79298-6-sj@kernel.org>
Date: Sun, 12 May 2024 12:36:56 -0700
From: SeongJae Park <sj@...nel.org>
To:
Cc: SeongJae Park <sj@...nel.org>,
damon@...ts.linux.dev,
linux-mm@...ck.org,
linux-kernel@...r.kernel.org
Subject: [RFC IDEA v2 5/6] mm/damon/acma: implement scale up feature
Implement the memory scale up feature of Access/Contiguity-aware Memory
Auto-scaling module. It runs DAMOS_FREE action scheme with
user-acceptable level of memory pressure stall as its target, in 512
contig pages base granularity. For minimizing DAMON-internal
DAMOS_ALLOC-ed region management overhead, the scheme is applied to only
128 MiB not-completely-allocated contiguous memory region of lowest
address.
Note that it does nothing with free_callback() since the host will
notify in-guest use of the page via page fault and return it on demand.
Signed-off-by: SeongJae Park <sj@...nel.org>
---
mm/damon/acma.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 90 insertions(+), 4 deletions(-)
diff --git a/mm/damon/acma.c b/mm/damon/acma.c
index b093b90471dd..32827cbf2fa7 100644
--- a/mm/damon/acma.c
+++ b/mm/damon/acma.c
@@ -54,6 +54,13 @@ module_param(commit_inputs, bool, 0600);
static unsigned long min_mem_kb __read_mostly;
module_param(min_mem, ulong, 0600);
+/*
+ * Maximum amount of memory to be guaranteed to the system. In other words,
+ * the upper limit of the scaling.
+ */
+static unsigned long max_mem_kb __read_mostly;
+module_param(max_mem, ulong, 0600);
+
/*
* Desired level of memory pressure-stall time in microseconds.
*
@@ -144,6 +151,11 @@ DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_acma_scale_down_stat,
acma_scale_down_tried_regions, acma_scale_down_succ_regions,
acma_scale_down_quota_exceeds);
+static struct damos_stat damon_acma_scale_up_stat;
+DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_acma_scale_up_stat,
+ acma_scale_up_tried_regions, acma_scale_up_succ_regions,
+ acma_scale_up_quota_exceeds);
+
static struct damos_access_pattern damon_acma_stub_pattern = {
/* Find regions having PAGE_SIZE or larger size */
.min_sz_region = PAGE_SIZE,
@@ -164,8 +176,8 @@ static struct damos *damon_acma_new_scheme(
{
struct damos_quota quota = damon_acma_quota;
- /* Use 1/2 of total quota for hot/cold pages sorting */
- quota.ms = quota.ms / 2;
+ /* Use 1/3 of total quota for hot/cold pages sorting */
+ quota.ms = quota.ms / 3;
return damon_new_scheme(
pattern,
@@ -246,6 +258,36 @@ static int damon_acma_set_scale_down_region_filter(struct damos *scheme)
return 0;
}
+/*
+ * Similar to damon_acma_set_scale_down_region_filter() but for scaling up.
+ */
+static int damon_acma_set_scale_up_region_filter(struct damos *scheme)
+{
+ struct damos_filter *filter = damos_new_filter(
+ DAMOS_FILTER_TYPE_ADDR, false);
+ unsigned long start;
+ unsigned long start_limit, end_limit;
+
+ if (!filter)
+ return -ENOMEM;
+
+ /* scale up no above max_mem_kb */
+ start_limit = monitor_region_start;
+ end_limit = start_limit + max_mem_kb * KB;
+
+ /* not-completely-free-ed SCALE_WINDOW region of lowest address */
+ for (start = start_limit; start <= end_limit - SCALE_WINDOW;
+ start += SCALE_WINDOW) {
+ if (damon_alloced_bytes(end - SCALE_WINDOW))
+ break;
+ }
+ filter->addr_range.start = start;
+ filter->addr_range.end = min(end_limit, start + SCALE_WINDOW);
+
+ damos_add_filter(scheme, filter);
+ return 0;
+}
+
/*
* Called back from DAMOS for every damos->alloc_order contig pages that
* just successfully DAMOS_ALLOC-ed.
@@ -307,11 +349,40 @@ static struct damos *damon_acma_new_scale_down_scheme(struct damos *old)
return scheme;
}
+/*
+ * Scale up scheme
+ */
+static struct damos *damon_acma_new_scale_up_scheme(void)
+{
+ struct damos_access_pattern pattern = damon_acma_stub_pattern;
+ struct damos *scheme;
+ int err;
+
+ scheme = damon_acma_new_scheme(&pattern, DAMOS_FREE);
+ if (!scheme)
+ return NULL;
+ err = damon_acma_set_scheme_quota(scheme, old,
+ DAMOS_QUOTA_SOME_MEM_PUSI_US);
+ if (err) {
+ damon_destroy_scheme(scheme);
+ return NULL;
+ }
+ scheme->alloc_order = scale_pg_order;
+ scheme->alloc_callback = NULL;
+ err = damon_acma_set_scale_up_region_filter(scale_up_scheme);
+ if (err) {
+ damon_destroy_scheme(scale_down_scheme);
+ return NULL;
+ }
+ return scheme;
+}
+
static int damon_acma_apply_parameters(void)
{
struct damos *scheme, *reclaim_scheme;
- struct damos *scale_down_scheme;
+ struct damos *scale_down_scheme, *scale_up_scheme;
struct damos *old_reclaim_scheme = NULL, *old_scale_down_scheme = NULL;
+ struct damos *old_scale_up_scheme = NULL;
struct damos_quota_goal *goal;
int err = 0;
@@ -324,7 +395,11 @@ static int damon_acma_apply_parameters(void)
old_reclaim_scheme = scheme;
continue;
}
- old_scale_down_scheme = scheme;
+ if (!old_scale_down_scheme) {
+ old_scale_down_scheme = scheme;
+ continue;
+ }
+ old_scale_up_scheme = scheme;
}
reclaim_scheme = damon_acma_new_reclaim_scheme(old_reclaim_scheme);
@@ -340,6 +415,14 @@ static int damon_acma_apply_parameters(void)
}
damon_add_scheme(ctx, scale_down_scheme);
+ scale_up_scheme = damon_acma_new_scale_up_scheme(old_scale_up_scheme);
+ if (!scale_up_scheme) {
+ damon_destroy_scheme(scale_down_scheme);
+ damon_destroy_scheme(reclaim_scheme);
+ return -ENOMEM;
+ }
+ damon_add_scheme(ctx, scale_up_scheme);
+
return damon_set_region_biggest_system_ram_default(target,
&monitor_region_start,
&monitor_region_end);
@@ -428,6 +511,9 @@ static int damon_acma_after_aggregation(struct damon_ctx *c)
case DAMOS_ALLOC:
damon_acma_scale_down_stat = s->stat;
break;
+ case DAMOS_FREE:
+ damon_acma_scale_up_stat = s->stat;
+ break;
default:
break;
}
--
2.39.2
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