The patch titled
Subject: samples/damon: introduce a skeleton of a smaple DAMON module for proactive reclamation
has been added to the -mm mm-unstable branch. Its filename is
samples-damon-introduce-a-skeleton-of-a-smaple-damon-module-for-proactive-reclamation.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/samples-damon-introduce-a-skeleton-of-a-smaple-damon-module-for-proactive-reclamation.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: SeongJae Park <sj@xxxxxxxxxx>
Subject: samples/damon: introduce a skeleton of a smaple DAMON module for proactive reclamation
Date: Tue, 10 Dec 2024 13:50:29 -0800
DAMON is not only for monitoring of access patterns, but also for
access-aware system operations. For the system operations, DAMON provides
a feature called DAMOS (Data Access Monitoring-based Operation Schemes).
There is no sample API usage of DAMOS, though. Copy the working set size
estimation sample modules with changed names of the module and symbols, to
use it as a skeleton for a sample module showing the DAMOS API usage. The
following commit will make it proactively reclaim cold memory of the given
process, using DAMOS.
Link: https://lkml.kernel.org/r/20241210215030.85675-5-sj@xxxxxxxxxx
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
samples/Makefile | 1
samples/damon/Kconfig | 13 ++++
samples/damon/Makefile | 1
samples/damon/prcl.c | 116 +++++++++++++++++++++++++++++++++++++++
4 files changed, 131 insertions(+)
--- a/samples/damon/Kconfig~samples-damon-introduce-a-skeleton-of-a-smaple-damon-module-for-proactive-reclamation
+++ a/samples/damon/Kconfig
@@ -14,4 +14,17 @@ config SAMPLE_DAMON_WSSE
If unsure, say N.
+config SAMPLE_DAMON_PRCL
+ bool "DAMON sameple module for access-aware proactive reclamation"
+ depends on DAMON && DAMON_VADDR
+ help
+ This builds DAMON sample module for access-aware proactive
+ reclamation.
+
+ The module receives a pid, monitor access to the virtual address
+ space of the process, find memory regions that not accessed, and
+ proactively reclaim the regions.
+
+ If unsure, say N.
+
endmenu
--- a/samples/damon/Makefile~samples-damon-introduce-a-skeleton-of-a-smaple-damon-module-for-proactive-reclamation
+++ a/samples/damon/Makefile
@@ -1,3 +1,4 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_SAMPLE_DAMON_WSSE) += wsse.o
+obj-$(CONFIG_SAMPLE_DAMON_PRCL) += prcl.o
diff --git a/samples/damon/prcl.c a/samples/damon/prcl.c
new file mode 100644
--- /dev/null
+++ a/samples/damon/prcl.c
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * proactive reclamation: monitor access pattern of a given process, find
+ * regiosn that seems not accessed, and proactively page out the regions.
+ */
+
+#define pr_fmt(fmt) "damon_sample_prcl: " fmt
+
+#include <linux/damon.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+static int target_pid __read_mostly;
+module_param(target_pid, int, 0600);
+
+static int damon_sample_prcl_enable_store(
+ const char *val, const struct kernel_param *kp);
+
+static const struct kernel_param_ops enable_param_ops = {
+ .set = damon_sample_prcl_enable_store,
+ .get = param_get_bool,
+};
+
+static bool enable __read_mostly;
+module_param_cb(enable, &enable_param_ops, &enable, 0600);
+MODULE_PARM_DESC(enable, "Enable of disable DAMON_SAMPLE_WSSE");
+
+static struct damon_ctx *ctx;
+static struct pid *target_pidp;
+
+static int damon_sample_prcl_after_aggregate(struct damon_ctx *c)
+{
+ struct damon_target *t;
+
+ damon_for_each_target(t, c) {
+ struct damon_region *r;
+ unsigned long wss = 0;
+
+ damon_for_each_region(r, t) {
+ if (r->nr_accesses > 0)
+ wss += r->ar.end - r->ar.start;
+ }
+ pr_info("wss: %lu\n", wss);
+ }
+ return 0;
+}
+
+static int damon_sample_prcl_start(void)
+{
+ struct damon_target *target;
+
+ pr_info("start\n");
+
+ ctx = damon_new_ctx();
+ if (!ctx)
+ return -ENOMEM;
+ if (damon_select_ops(ctx, DAMON_OPS_VADDR)) {
+ damon_destroy_ctx(ctx);
+ return -EINVAL;
+ }
+
+ target = damon_new_target();
+ if (!target) {
+ damon_destroy_ctx(ctx);
+ return -ENOMEM;
+ }
+ damon_add_target(ctx, target);
+ target_pidp = find_get_pid(target_pid);
+ if (!target_pidp) {
+ damon_destroy_ctx(ctx);
+ return -EINVAL;
+ }
+ target->pid = target_pidp;
+
+ ctx->callback.after_aggregation = damon_sample_prcl_after_aggregate;
+
+ return damon_start(&ctx, 1, true);
+}
+
+static void damon_sample_prcl_stop(void)
+{
+ pr_info("stop\n");
+ if (ctx) {
+ damon_stop(&ctx, 1);
+ damon_destroy_ctx(ctx);
+ }
+ if (target_pidp)
+ put_pid(target_pidp);
+}
+
+static int damon_sample_prcl_enable_store(
+ const char *val, const struct kernel_param *kp)
+{
+ bool enabled = enable;
+ int err;
+
+ err = kstrtobool(val, &enable);
+ if (err)
+ return err;
+
+ if (enable == enabled)
+ return 0;
+
+ if (enable)
+ return damon_sample_prcl_start();
+ damon_sample_prcl_stop();
+ return 0;
+}
+
+static int __init damon_sample_prcl_init(void)
+{
+ return 0;
+}
+
+module_init(damon_sample_prcl_init);
--- a/samples/Makefile~samples-damon-introduce-a-skeleton-of-a-smaple-damon-module-for-proactive-reclamation
+++ a/samples/Makefile
@@ -40,3 +40,4 @@ obj-$(CONFIG_SAMPLE_CORESIGHT_SYSCFG) +=
obj-$(CONFIG_SAMPLE_FPROBE) += fprobe/
obj-$(CONFIG_SAMPLES_RUST) += rust/
obj-$(CONFIG_SAMPLE_DAMON_WSSE) += damon/
+obj-$(CONFIG_SAMPLE_DAMON_PRCL) += damon/
_
Patches currently in -mm which might be from sj@xxxxxxxxxx are
samples-add-a-skeleton-of-a-sample-damon-module-for-working-set-size-estimation.patch
samples-damon-wsse-start-and-stop-damon-as-the-user-requests.patch
samples-damon-wsse-implement-working-set-size-estimation-and-logging.patch
samples-damon-introduce-a-skeleton-of-a-smaple-damon-module-for-proactive-reclamation.patch
samples-damon-prcl-implement-schemes-setup.patch
