diff options
Diffstat (limited to 'mm/damon/lru_sort.c')
| -rw-r--r-- | mm/damon/lru_sort.c | 548 |
1 files changed, 548 insertions, 0 deletions
diff --git a/mm/damon/lru_sort.c b/mm/damon/lru_sort.c new file mode 100644 index 000000000000..9de6f00a71c5 --- /dev/null +++ b/mm/damon/lru_sort.c @@ -0,0 +1,548 @@ +// 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)) { + damon_destroy_ctx(ctx); + 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); |