--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DAMON-based LRU-lists Sorting
+ *
+ * Author: SeongJae Park <sj@kernel.org>
+ */
+
+#define pr_fmt(fmt) "damon-lru-sort: " fmt
+
+#include <linux/damon.h>
+#include <linux/ioport.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/workqueue.h>
+
+#ifdef MODULE_PARAM_PREFIX
+#undef MODULE_PARAM_PREFIX
+#endif
+#define MODULE_PARAM_PREFIX "damon_lru_sort."
+
+/*
+ * Enable or disable DAMON_LRU_SORT.
+ *
+ * You can enable DAMON_LRU_SORT by setting the value of this parameter as
+ * ``Y``. Setting it as ``N`` disables DAMON_LRU_SORT. Note that
+ * DAMON_LRU_SORT could do no real monitoring and LRU-lists sorting due to the
+ * watermarks-based activation condition. Refer to below descriptions for the
+ * watermarks parameter for this.
+ */
+static bool enabled __read_mostly;
+
+/*
+ * Make DAMON_LRU_SORT reads the input parameters again, except ``enabled``.
+ *
+ * Input parameters that updated while DAMON_LRU_SORT is running are not
+ * applied by default. Once this parameter is set as ``Y``, DAMON_LRU_SORT
+ * reads values of parametrs except ``enabled`` again. Once the re-reading is
+ * done, this parameter is set as ``N``. If invalid parameters are found while
+ * the re-reading, DAMON_LRU_SORT will be disabled.
+ */
+static bool commit_inputs __read_mostly;
+module_param(commit_inputs, bool, 0600);
+
+/*
+ * Access frequency threshold for hot memory regions identification in permil.
+ *
+ * If a memory region is accessed in frequency of this or higher,
+ * DAMON_LRU_SORT identifies the region as hot, and mark it as accessed on the
+ * LRU list, so that it could not be reclaimed under memory pressure. 50% by
+ * default.
+ */
+static unsigned long hot_thres_access_freq = 500;
+module_param(hot_thres_access_freq, ulong, 0600);
+
+/*
+ * Time threshold for cold memory regions identification in microseconds.
+ *
+ * If a memory region is not accessed for this or longer time, DAMON_LRU_SORT
+ * identifies the region as cold, and mark it as unaccessed on the LRU list, so
+ * that it could be reclaimed first under memory pressure. 120 seconds by
+ * default.
+ */
+static unsigned long cold_min_age __read_mostly = 120000000;
+module_param(cold_min_age, ulong, 0600);
+
+/*
+ * Limit of time for trying the LRU lists sorting in milliseconds.
+ *
+ * DAMON_LRU_SORT tries to use only up to this time within a time window
+ * (quota_reset_interval_ms) for trying LRU lists sorting. This can be used
+ * for limiting CPU consumption of DAMON_LRU_SORT. If the value is zero, the
+ * limit is disabled.
+ *
+ * 10 ms by default.
+ */
+static unsigned long quota_ms __read_mostly = 10;
+module_param(quota_ms, ulong, 0600);
+
+/*
+ * The time quota charge reset interval in milliseconds.
+ *
+ * The charge reset interval for the quota of time (quota_ms). That is,
+ * DAMON_LRU_SORT does not try LRU-lists sorting for more than quota_ms
+ * milliseconds or quota_sz bytes within quota_reset_interval_ms milliseconds.
+ *
+ * 1 second by default.
+ */
+static unsigned long quota_reset_interval_ms __read_mostly = 1000;
+module_param(quota_reset_interval_ms, ulong, 0600);
+
+/*
+ * The watermarks check time interval in microseconds.
+ *
+ * Minimal time to wait before checking the watermarks, when DAMON_LRU_SORT is
+ * enabled but inactive due to its watermarks rule. 5 seconds by default.
+ */
+static unsigned long wmarks_interval __read_mostly = 5000000;
+module_param(wmarks_interval, ulong, 0600);
+
+/*
+ * Free memory rate (per thousand) for the high watermark.
+ *
+ * If free memory of the system in bytes per thousand bytes is higher than
+ * this, DAMON_LRU_SORT becomes inactive, so it does nothing but periodically
+ * checks the watermarks. 200 (20%) by default.
+ */
+static unsigned long wmarks_high __read_mostly = 200;
+module_param(wmarks_high, ulong, 0600);
+
+/*
+ * Free memory rate (per thousand) for the middle watermark.
+ *
+ * If free memory of the system in bytes per thousand bytes is between this and
+ * the low watermark, DAMON_LRU_SORT becomes active, so starts the monitoring
+ * and the LRU-lists sorting. 150 (15%) by default.
+ */
+static unsigned long wmarks_mid __read_mostly = 150;
+module_param(wmarks_mid, ulong, 0600);
+
+/*
+ * Free memory rate (per thousand) for the low watermark.
+ *
+ * If free memory of the system in bytes per thousand bytes is lower than this,
+ * DAMON_LRU_SORT becomes inactive, so it does nothing but periodically checks
+ * the watermarks. 50 (5%) by default.
+ */
+static unsigned long wmarks_low __read_mostly = 50;
+module_param(wmarks_low, ulong, 0600);
+
+/*
+ * Sampling interval for the monitoring in microseconds.
+ *
+ * The sampling interval of DAMON for the hot/cold memory monitoring. Please
+ * refer to the DAMON documentation for more detail. 5 ms by default.
+ */
+static unsigned long sample_interval __read_mostly = 5000;
+module_param(sample_interval, ulong, 0600);
+
+/*
+ * Aggregation interval for the monitoring in microseconds.
+ *
+ * The aggregation interval of DAMON for the hot/cold memory monitoring.
+ * Please refer to the DAMON documentation for more detail. 100 ms by default.
+ */
+static unsigned long aggr_interval __read_mostly = 100000;
+module_param(aggr_interval, ulong, 0600);
+
+/*
+ * Minimum number of monitoring regions.
+ *
+ * The minimal number of monitoring regions of DAMON for the hot/cold memory
+ * monitoring. This can be used to set lower-bound of the monitoring quality.
+ * But, setting this too high could result in increased monitoring overhead.
+ * Please refer to the DAMON documentation for more detail. 10 by default.
+ */
+static unsigned long min_nr_regions __read_mostly = 10;
+module_param(min_nr_regions, ulong, 0600);
+
+/*
+ * Maximum number of monitoring regions.
+ *
+ * The maximum number of monitoring regions of DAMON for the hot/cold memory
+ * monitoring. This can be used to set upper-bound of the monitoring overhead.
+ * However, setting this too low could result in bad monitoring quality.
+ * Please refer to the DAMON documentation for more detail. 1000 by default.
+ */
+static unsigned long max_nr_regions __read_mostly = 1000;
+module_param(max_nr_regions, ulong, 0600);
+
+/*
+ * Start of the target memory region in physical address.
+ *
+ * The start physical address of memory region that DAMON_LRU_SORT will do work
+ * against. By default, biggest System RAM is used as the region.
+ */
+static unsigned long monitor_region_start __read_mostly;
+module_param(monitor_region_start, ulong, 0600);
+
+/*
+ * End of the target memory region in physical address.
+ *
+ * The end physical address of memory region that DAMON_LRU_SORT will do work
+ * against. By default, biggest System RAM is used as the region.
+ */
+static unsigned long monitor_region_end __read_mostly;
+module_param(monitor_region_end, ulong, 0600);
+
+/*
+ * PID of the DAMON thread
+ *
+ * If DAMON_LRU_SORT is enabled, this becomes the PID of the worker thread.
+ * Else, -1.
+ */
+static int kdamond_pid __read_mostly = -1;
+module_param(kdamond_pid, int, 0400);
+
+/*
+ * Number of hot memory regions that tried to be LRU-sorted.
+ */
+static unsigned long nr_lru_sort_tried_hot_regions __read_mostly;
+module_param(nr_lru_sort_tried_hot_regions, ulong, 0400);
+
+/*
+ * Total bytes of hot memory regions that tried to be LRU-sorted.
+ */
+static unsigned long bytes_lru_sort_tried_hot_regions __read_mostly;
+module_param(bytes_lru_sort_tried_hot_regions, ulong, 0400);
+
+/*
+ * Number of hot memory regions that successfully be LRU-sorted.
+ */
+static unsigned long nr_lru_sorted_hot_regions __read_mostly;
+module_param(nr_lru_sorted_hot_regions, ulong, 0400);
+
+/*
+ * Total bytes of hot memory regions that successfully be LRU-sorted.
+ */
+static unsigned long bytes_lru_sorted_hot_regions __read_mostly;
+module_param(bytes_lru_sorted_hot_regions, ulong, 0400);
+
+/*
+ * Number of times that the time quota limit for hot regions have exceeded
+ */
+static unsigned long nr_hot_quota_exceeds __read_mostly;
+module_param(nr_hot_quota_exceeds, ulong, 0400);
+
+/*
+ * Number of cold memory regions that tried to be LRU-sorted.
+ */
+static unsigned long nr_lru_sort_tried_cold_regions __read_mostly;
+module_param(nr_lru_sort_tried_cold_regions, ulong, 0400);
+
+/*
+ * Total bytes of cold memory regions that tried to be LRU-sorted.
+ */
+static unsigned long bytes_lru_sort_tried_cold_regions __read_mostly;
+module_param(bytes_lru_sort_tried_cold_regions, ulong, 0400);
+
+/*
+ * Number of cold memory regions that successfully be LRU-sorted.
+ */
+static unsigned long nr_lru_sorted_cold_regions __read_mostly;
+module_param(nr_lru_sorted_cold_regions, ulong, 0400);
+
+/*
+ * Total bytes of cold memory regions that successfully be LRU-sorted.
+ */
+static unsigned long bytes_lru_sorted_cold_regions __read_mostly;
+module_param(bytes_lru_sorted_cold_regions, ulong, 0400);
+
+/*
+ * Number of times that the time quota limit for cold regions have exceeded
+ */
+static unsigned long nr_cold_quota_exceeds __read_mostly;
+module_param(nr_cold_quota_exceeds, ulong, 0400);
+
+static struct damon_ctx *ctx;
+static struct damon_target *target;
+
+struct damon_lru_sort_ram_walk_arg {
+ unsigned long start;
+ unsigned long end;
+};
+
+static int walk_system_ram(struct resource *res, void *arg)
+{
+ struct damon_lru_sort_ram_walk_arg *a = arg;
+
+ if (a->end - a->start < resource_size(res)) {
+ a->start = res->start;
+ a->end = res->end;
+ }
+ return 0;
+}
+
+/*
+ * Find biggest 'System RAM' resource and store its start and end address in
+ * @start and @end, respectively. If no System RAM is found, returns false.
+ */
+static bool get_monitoring_region(unsigned long *start, unsigned long *end)
+{
+ struct damon_lru_sort_ram_walk_arg arg = {};
+
+ walk_system_ram_res(0, ULONG_MAX, &arg, walk_system_ram);
+ if (arg.end <= arg.start)
+ return false;
+
+ *start = arg.start;
+ *end = arg.end;
+ return true;
+}
+
+/* Create a DAMON-based operation scheme for hot memory regions */
+static struct damos *damon_lru_sort_new_hot_scheme(unsigned int hot_thres)
+{
+ struct damos_watermarks wmarks = {
+ .metric = DAMOS_WMARK_FREE_MEM_RATE,
+ .interval = wmarks_interval,
+ .high = wmarks_high,
+ .mid = wmarks_mid,
+ .low = wmarks_low,
+ };
+ struct damos_quota quota = {
+ /*
+ * Do not try LRU-lists sorting of hot pages for more than half
+ * of quota_ms milliseconds within quota_reset_interval_ms.
+ */
+ .ms = quota_ms / 2,
+ .sz = 0,
+ .reset_interval = quota_reset_interval_ms,
+ /* Within the quota, mark hotter regions accessed first. */
+ .weight_sz = 0,
+ .weight_nr_accesses = 1,
+ .weight_age = 0,
+ };
+ struct damos *scheme = damon_new_scheme(
+ /* Find regions having PAGE_SIZE or larger size */
+ PAGE_SIZE, ULONG_MAX,
+ /* and accessed for more than the threshold */
+ hot_thres, UINT_MAX,
+ /* no matter its age */
+ 0, UINT_MAX,
+ /* prioritize those on LRU lists, as soon as found */
+ DAMOS_LRU_PRIO,
+ /* under the quota. */
+ "a,
+ /* (De)activate this according to the watermarks. */
+ &wmarks);
+
+ return scheme;
+}
+
+/* Create a DAMON-based operation scheme for cold memory regions */
+static struct damos *damon_lru_sort_new_cold_scheme(unsigned int cold_thres)
+{
+ struct damos_watermarks wmarks = {
+ .metric = DAMOS_WMARK_FREE_MEM_RATE,
+ .interval = wmarks_interval,
+ .high = wmarks_high,
+ .mid = wmarks_mid,
+ .low = wmarks_low,
+ };
+ struct damos_quota quota = {
+ /*
+ * Do not try LRU-lists sorting of cold pages for more than
+ * half of quota_ms milliseconds within
+ * quota_reset_interval_ms.
+ */
+ .ms = quota_ms / 2,
+ .sz = 0,
+ .reset_interval = quota_reset_interval_ms,
+ /* Within the quota, mark colder regions not accessed first. */
+ .weight_sz = 0,
+ .weight_nr_accesses = 0,
+ .weight_age = 1,
+ };
+ struct damos *scheme = damon_new_scheme(
+ /* Find regions having PAGE_SIZE or larger size */
+ PAGE_SIZE, ULONG_MAX,
+ /* and not accessed at all */
+ 0, 0,
+ /* for cold_thres or more micro-seconds, and */
+ cold_thres, UINT_MAX,
+ /* mark those as not accessed, as soon as found */
+ DAMOS_LRU_DEPRIO,
+ /* under the quota. */
+ "a,
+ /* (De)activate this according to the watermarks. */
+ &wmarks);
+
+ return scheme;
+}
+
+static int damon_lru_sort_apply_parameters(void)
+{
+ struct damos *scheme, *next_scheme;
+ struct damon_addr_range addr_range;
+ unsigned int hot_thres, cold_thres;
+ int err = 0;
+
+ err = damon_set_attrs(ctx, sample_interval, aggr_interval, 0,
+ min_nr_regions, max_nr_regions);
+ if (err)
+ return err;
+
+ /* free previously set schemes */
+ damon_for_each_scheme_safe(scheme, next_scheme, ctx)
+ damon_destroy_scheme(scheme);
+
+ /* aggr_interval / sample_interval is the maximum nr_accesses */
+ hot_thres = aggr_interval / sample_interval * hot_thres_access_freq /
+ 1000;
+ scheme = damon_lru_sort_new_hot_scheme(hot_thres);
+ if (!scheme)
+ return -ENOMEM;
+ damon_add_scheme(ctx, scheme);
+
+ cold_thres = cold_min_age / aggr_interval;
+ scheme = damon_lru_sort_new_cold_scheme(cold_thres);
+ if (!scheme)
+ return -ENOMEM;
+ damon_add_scheme(ctx, scheme);
+
+ if (monitor_region_start > monitor_region_end)
+ return -EINVAL;
+ if (!monitor_region_start && !monitor_region_end &&
+ !get_monitoring_region(&monitor_region_start,
+ &monitor_region_end))
+ return -EINVAL;
+ addr_range.start = monitor_region_start;
+ addr_range.end = monitor_region_end;
+ return damon_set_regions(target, &addr_range, 1);
+}
+
+static int damon_lru_sort_turn(bool on)
+{
+ int err;
+
+ if (!on) {
+ err = damon_stop(&ctx, 1);
+ if (!err)
+ kdamond_pid = -1;
+ return err;
+ }
+
+ err = damon_lru_sort_apply_parameters();
+ if (err)
+ return err;
+
+ err = damon_start(&ctx, 1, true);
+ if (err)
+ return err;
+ kdamond_pid = ctx->kdamond->pid;
+ return 0;
+}
+
+static struct delayed_work damon_lru_sort_timer;
+static void damon_lru_sort_timer_fn(struct work_struct *work)
+{
+ static bool last_enabled;
+ bool now_enabled;
+
+ now_enabled = enabled;
+ if (last_enabled != now_enabled) {
+ if (!damon_lru_sort_turn(now_enabled))
+ last_enabled = now_enabled;
+ else
+ enabled = last_enabled;
+ }
+}
+static DECLARE_DELAYED_WORK(damon_lru_sort_timer, damon_lru_sort_timer_fn);
+
+static bool damon_lru_sort_initialized;
+
+static int damon_lru_sort_enabled_store(const char *val,
+ const struct kernel_param *kp)
+{
+ int rc = param_set_bool(val, kp);
+
+ if (rc < 0)
+ return rc;
+
+ if (!damon_lru_sort_initialized)
+ return rc;
+
+ schedule_delayed_work(&damon_lru_sort_timer, 0);
+
+ return 0;
+}
+
+static const struct kernel_param_ops enabled_param_ops = {
+ .set = damon_lru_sort_enabled_store,
+ .get = param_get_bool,
+};
+
+module_param_cb(enabled, &enabled_param_ops, &enabled, 0600);
+MODULE_PARM_DESC(enabled,
+ "Enable or disable DAMON_LRU_SORT (default: disabled)");
+
+static int damon_lru_sort_handle_commit_inputs(void)
+{
+ int err;
+
+ if (!commit_inputs)
+ return 0;
+
+ err = damon_lru_sort_apply_parameters();
+ commit_inputs = false;
+ return err;
+}
+
+static int damon_lru_sort_after_aggregation(struct damon_ctx *c)
+{
+ struct damos *s;
+
+ /* update the stats parameter */
+ damon_for_each_scheme(s, c) {
+ if (s->action == DAMOS_LRU_PRIO) {
+ nr_lru_sort_tried_hot_regions = s->stat.nr_tried;
+ bytes_lru_sort_tried_hot_regions = s->stat.sz_tried;
+ nr_lru_sorted_hot_regions = s->stat.nr_applied;
+ bytes_lru_sorted_hot_regions = s->stat.sz_applied;
+ nr_hot_quota_exceeds = s->stat.qt_exceeds;
+ } else if (s->action == DAMOS_LRU_DEPRIO) {
+ nr_lru_sort_tried_cold_regions = s->stat.nr_tried;
+ bytes_lru_sort_tried_cold_regions = s->stat.sz_tried;
+ nr_lru_sorted_cold_regions = s->stat.nr_applied;
+ bytes_lru_sorted_cold_regions = s->stat.sz_applied;
+ nr_cold_quota_exceeds = s->stat.qt_exceeds;
+ }
+ }
+
+ return damon_lru_sort_handle_commit_inputs();
+}
+
+static int damon_lru_sort_after_wmarks_check(struct damon_ctx *c)
+{
+ return damon_lru_sort_handle_commit_inputs();
+}
+
+static int __init damon_lru_sort_init(void)
+{
+ ctx = damon_new_ctx();
+ if (!ctx)
+ return -ENOMEM;
+
+ if (damon_select_ops(ctx, DAMON_OPS_PADDR))
+ return -EINVAL;
+
+ ctx->callback.after_wmarks_check = damon_lru_sort_after_wmarks_check;
+ ctx->callback.after_aggregation = damon_lru_sort_after_aggregation;
+
+ target = damon_new_target();
+ if (!target) {
+ damon_destroy_ctx(ctx);
+ return -ENOMEM;
+ }
+ damon_add_target(ctx, target);
+
+ schedule_delayed_work(&damon_lru_sort_timer, 0);
+
+ damon_lru_sort_initialized = true;
+ return 0;
+}
+
+module_init(damon_lru_sort_init);
projects / users / jedix / linux-maple.git / commitdiff