Add a sample DAMON application kernel module, namely damon_sample_prcl. It is same to the one of the example kernel modules that presented at kernel summit 2021 with 10 minutes live coding[1] but updated for the latest DAMON interface. The sample module receives a pid of a process to monitor the access, monitors the access to the virtual address space of the process, find regions that not accessed and proactively reclaim those using DAMOS. [1] https://linuxplumbersconf.org/event/11/contributions/984/ Signed-off-by: SeongJae Park <sj@xxxxxxxxxx> --- samples/damon/Kconfig | 13 ++++ samples/damon/Makefile | 1 + samples/damon/damon_sample_prcl.c | 102 ++++++++++++++++++++++++++++++ 3 files changed, 116 insertions(+) create mode 100644 samples/damon/damon_sample_prcl.c diff --git a/samples/damon/Kconfig b/samples/damon/Kconfig index f8b9a73717f9..459042ce5958 100644 --- a/samples/damon/Kconfig +++ b/samples/damon/Kconfig @@ -14,4 +14,17 @@ config SAMPLE_DAMON_WSSE If unsure, say N. +config SAMPLE_DAMON_PRCL + tristate "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 pid of a process, 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 diff --git a/samples/damon/Makefile b/samples/damon/Makefile index 1ace3ad4aff0..509f6a619dc4 100644 --- a/samples/damon/Makefile +++ b/samples/damon/Makefile @@ -1,2 +1,3 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_SAMPLE_DAMON_WSSE) += damon_sample_wsse.o +obj-$(CONFIG_SAMPLE_DAMON_PRCL) += damon_sample_prcl.o diff --git a/samples/damon/damon_sample_prcl.c b/samples/damon/damon_sample_prcl.c new file mode 100644 index 000000000000..487196f18864 --- /dev/null +++ b/samples/damon/damon_sample_prcl.c @@ -0,0 +1,102 @@ +// 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 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 __init damon_sample_prcl_init(void) +{ + struct damon_target *target; + struct damos *scheme; + + pr_info("Hello\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; + + scheme = damon_new_scheme( + &(struct damos_access_pattern) { + .min_sz_region = PAGE_SIZE, + .max_sz_region = ULONG_MAX, + .min_nr_accesses = 0, + .max_nr_accesses = 0}, + DAMOS_PAGEOUT, + 0, + &(struct damos_quota){}, + &(struct damos_watermarks){}); + if (!scheme) { + damon_destroy_ctx(ctx); + return -ENOMEM; + } + damon_set_schemes(ctx, &scheme, 1); + + return damon_start(&ctx, 1, true); +} + +static void __exit damon_sample_prcl_exit(void) +{ + pr_info("Goodbye\n"); + if (ctx) { + damon_stop(&ctx, 1); + damon_destroy_ctx(ctx); + } + if (target_pidp) + put_pid(target_pidp); +} + +module_init(damon_sample_prcl_init); +module_exit(damon_sample_prcl_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("SeongJae Park"); +MODULE_DESCRIPTION("DAMON sample module for proactive reclamation"); -- 2.34.1
