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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // 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. */
             &quota,
             /* (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. */
             &quota,
             /* (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);

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