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mm/damon/sysfs: support DAMOS stats
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This commit makes DAMON sysfs interface supports the DAMOS stats feature.
Specifically, this commit adds 'stats' directory under each scheme
directory, and update the contents of the files under the directory
according to the latest monitoring results, when the user writes special
keyword, 'update_schemes_stats' to the 'state' file of the kdamond.

As a result, the files hierarchy becomes as below:

    /sys/kernel/mm/damon/admin
    │ kdamonds/nr_kdamonds
    │ │ 0/state,pid
    │ │ │ contexts/nr_contexts
    │ │ │ │ 0/operations
    │ │ │ │ │ monitoring_attrs/intervals/sample_us,aggr_us,update_us
    │ │ │ │ │ │ nr_regions/min,max
    │ │ │ │ │ targets/nr_targets
    │ │ │ │ │ │ 0/pid_target
    │ │ │ │ │ │ │ regions/nr_regions
    │ │ │ │ │ │ │ │ 0/start,end
    │ │ │ │ │ │ │ │ ...
    │ │ │ │ │ │ ...
    │ │ │ │ │ schemes/nr_schemes
    │ │ │ │ │ │ 0/action
    │ │ │ │ │ │ │ access_pattern/
    │ │ │ │ │ │ │ │ sz/min,max
    │ │ │ │ │ │ │ │ nr_accesses/min,max
    │ │ │ │ │ │ │ │ age/min,max
    │ │ │ │ │ │ │ quotas/ms,sz,reset_interval_ms
    │ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil
    │ │ │ │ │ │ │ watermarks/metric,interval_us,high,mid,low
    │ │ │ │ │ │ │ stats/    <- NEW DIRECTORY
    │ │ │ │ │ │ │ │ nr_tried,sz_tried,nr_applied,sz_applied,qt_exceeds
    │ │ │ │ │ │ ...
    │ │ │ │ ...
    │ │ ...

Link: https://lkml.kernel.org/r/20220228081314.5770-11-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Xin Hao <xhao@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored and Linus Torvalds committed Mar 22, 2022
1 parent 1b32234 commit 0ac32b8
Showing 1 changed file with 150 additions and 0 deletions.
150 changes: 150 additions & 0 deletions mm/damon/sysfs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -113,6 +113,105 @@ static struct kobj_type damon_sysfs_ul_range_ktype = {
.default_groups = damon_sysfs_ul_range_groups,
};

/*
* schemes/stats directory
*/

struct damon_sysfs_stats {
struct kobject kobj;
unsigned long nr_tried;
unsigned long sz_tried;
unsigned long nr_applied;
unsigned long sz_applied;
unsigned long qt_exceeds;
};

static struct damon_sysfs_stats *damon_sysfs_stats_alloc(void)
{
return kzalloc(sizeof(struct damon_sysfs_stats), GFP_KERNEL);
}

static ssize_t nr_tried_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_stats *stats = container_of(kobj,
struct damon_sysfs_stats, kobj);

return sysfs_emit(buf, "%lu\n", stats->nr_tried);
}

static ssize_t sz_tried_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_stats *stats = container_of(kobj,
struct damon_sysfs_stats, kobj);

return sysfs_emit(buf, "%lu\n", stats->sz_tried);
}

static ssize_t nr_applied_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_stats *stats = container_of(kobj,
struct damon_sysfs_stats, kobj);

return sysfs_emit(buf, "%lu\n", stats->nr_applied);
}

static ssize_t sz_applied_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_stats *stats = container_of(kobj,
struct damon_sysfs_stats, kobj);

return sysfs_emit(buf, "%lu\n", stats->sz_applied);
}

static ssize_t qt_exceeds_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_stats *stats = container_of(kobj,
struct damon_sysfs_stats, kobj);

return sysfs_emit(buf, "%lu\n", stats->qt_exceeds);
}

static void damon_sysfs_stats_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_stats, kobj));
}

static struct kobj_attribute damon_sysfs_stats_nr_tried_attr =
__ATTR_RO_MODE(nr_tried, 0400);

static struct kobj_attribute damon_sysfs_stats_sz_tried_attr =
__ATTR_RO_MODE(sz_tried, 0400);

static struct kobj_attribute damon_sysfs_stats_nr_applied_attr =
__ATTR_RO_MODE(nr_applied, 0400);

static struct kobj_attribute damon_sysfs_stats_sz_applied_attr =
__ATTR_RO_MODE(sz_applied, 0400);

static struct kobj_attribute damon_sysfs_stats_qt_exceeds_attr =
__ATTR_RO_MODE(qt_exceeds, 0400);

static struct attribute *damon_sysfs_stats_attrs[] = {
&damon_sysfs_stats_nr_tried_attr.attr,
&damon_sysfs_stats_sz_tried_attr.attr,
&damon_sysfs_stats_nr_applied_attr.attr,
&damon_sysfs_stats_sz_applied_attr.attr,
&damon_sysfs_stats_qt_exceeds_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_stats);

static struct kobj_type damon_sysfs_stats_ktype = {
.release = damon_sysfs_stats_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_stats_groups,
};

/*
* watermarks directory
*/
Expand Down Expand Up @@ -653,6 +752,7 @@ struct damon_sysfs_scheme {
struct damon_sysfs_access_pattern *access_pattern;
struct damon_sysfs_quotas *quotas;
struct damon_sysfs_watermarks *watermarks;
struct damon_sysfs_stats *stats;
};

/* This should match with enum damos_action */
Expand Down Expand Up @@ -743,6 +843,22 @@ static int damon_sysfs_scheme_set_watermarks(struct damon_sysfs_scheme *scheme)
return err;
}

static int damon_sysfs_scheme_set_stats(struct damon_sysfs_scheme *scheme)
{
struct damon_sysfs_stats *stats = damon_sysfs_stats_alloc();
int err;

if (!stats)
return -ENOMEM;
err = kobject_init_and_add(&stats->kobj, &damon_sysfs_stats_ktype,
&scheme->kobj, "stats");
if (err)
kobject_put(&stats->kobj);
else
scheme->stats = stats;
return err;
}

static int damon_sysfs_scheme_add_dirs(struct damon_sysfs_scheme *scheme)
{
int err;
Expand All @@ -756,8 +872,14 @@ static int damon_sysfs_scheme_add_dirs(struct damon_sysfs_scheme *scheme)
err = damon_sysfs_scheme_set_watermarks(scheme);
if (err)
goto put_quotas_access_pattern_out;
err = damon_sysfs_scheme_set_stats(scheme);
if (err)
goto put_watermarks_quotas_access_pattern_out;
return 0;

put_watermarks_quotas_access_pattern_out:
kobject_put(&scheme->watermarks->kobj);
scheme->watermarks = NULL;
put_quotas_access_pattern_out:
kobject_put(&scheme->quotas->kobj);
scheme->quotas = NULL;
Expand All @@ -774,6 +896,7 @@ static void damon_sysfs_scheme_rm_dirs(struct damon_sysfs_scheme *scheme)
damon_sysfs_quotas_rm_dirs(scheme->quotas);
kobject_put(&scheme->quotas->kobj);
kobject_put(&scheme->watermarks->kobj);
kobject_put(&scheme->stats->kobj);
}

static ssize_t action_show(struct kobject *kobj, struct kobj_attribute *attr,
Expand Down Expand Up @@ -2141,6 +2264,31 @@ static int damon_sysfs_turn_damon_off(struct damon_sysfs_kdamond *kdamond)
*/
}

static int damon_sysfs_update_schemes_stats(struct damon_sysfs_kdamond *kdamond)
{
struct damon_ctx *ctx = kdamond->damon_ctx;
struct damos *scheme;
int schemes_idx = 0;

if (!ctx)
return -EINVAL;
mutex_lock(&ctx->kdamond_lock);
damon_for_each_scheme(scheme, ctx) {
struct damon_sysfs_schemes *sysfs_schemes;
struct damon_sysfs_stats *sysfs_stats;

sysfs_schemes = kdamond->contexts->contexts_arr[0]->schemes;
sysfs_stats = sysfs_schemes->schemes_arr[schemes_idx++]->stats;
sysfs_stats->nr_tried = scheme->stat.nr_tried;
sysfs_stats->sz_tried = scheme->stat.sz_tried;
sysfs_stats->nr_applied = scheme->stat.nr_applied;
sysfs_stats->sz_applied = scheme->stat.sz_applied;
sysfs_stats->qt_exceeds = scheme->stat.qt_exceeds;
}
mutex_unlock(&ctx->kdamond_lock);
return 0;
}

static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
Expand All @@ -2154,6 +2302,8 @@ static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
ret = damon_sysfs_turn_damon_on(kdamond);
else if (sysfs_streq(buf, "off"))
ret = damon_sysfs_turn_damon_off(kdamond);
else if (sysfs_streq(buf, "update_schemes_stats"))
ret = damon_sysfs_update_schemes_stats(kdamond);
else
ret = -EINVAL;
mutex_unlock(&damon_sysfs_lock);
Expand Down

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