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Message-Id: <20220908184356.103133-1-sj@kernel.org>
Date: Thu, 8 Sep 2022 18:43:56 +0000
From: SeongJae Park <sj@...nel.org>
To: Yajun Deng <yajun.deng@...ux.dev>
Cc: sj@...nel.org, akpm@...ux-foundation.org, damon@...ts.linux.dev,
linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] mm/damon: introduce struct damos_access_pattern
Hi Yajun,
On Thu, 8 Sep 2022 11:26:11 +0800 Yajun Deng <yajun.deng@...ux.dev> wrote:
> The damon_new_scheme() has too many parameters, we can introduce struct
> damos_access_pattern to simplify it.
>
> In additon, we couldn't use bpf trace kprobe that more than 5 parameters.
>
> v2:
> - make the name of structure more sense.
Let's not put the change log here, but three lines after, after the marker line
('---')[1].
Also, providing the lore link to the previous version, e.g.,
https://lore.kernel.org/damon/20220907092626.3013765-1-yajun.deng@linux.dev/
for this case, in the change log would be a good practice.
[1] https://docs.kernel.org/process/submitting-patches.html#the-canonical-patch-format
>
> Signed-off-by: Yajun Deng <yajun.deng@...ux.dev>
> ---
> include/linux/damon.h | 38 +++++++++++++++++++----------------
> mm/damon/core.c | 31 ++++++++++++++---------------
> mm/damon/dbgfs.c | 22 +++++++++++----------
> mm/damon/lru_sort.c | 46 ++++++++++++++++++++++++++-----------------
> mm/damon/reclaim.c | 23 +++++++++++++---------
> mm/damon/sysfs.c | 16 ++++++++++-----
> 6 files changed, 101 insertions(+), 75 deletions(-)
>
> diff --git a/include/linux/damon.h b/include/linux/damon.h
> index 7b1f4a488230..7ddfb4551a13 100644
> --- a/include/linux/damon.h
> +++ b/include/linux/damon.h
> @@ -216,13 +216,27 @@ struct damos_stat {
> };
>
> /**
> - * struct damos - Represents a Data Access Monitoring-based Operation Scheme.
> + * struct damos_access_pattern - Specify the access pattern of target regions.
> * @min_sz_region: Minimum size of target regions.
> * @max_sz_region: Maximum size of target regions.
> * @min_nr_accesses: Minimum ``->nr_accesses`` of target regions.
> * @max_nr_accesses: Maximum ``->nr_accesses`` of target regions.
> * @min_age_region: Minimum age of target regions.
> * @max_age_region: Maximum age of target regions.
> + */
> +
Unnecessary new line. Let's remove it.
> +struct damos_access_pattern {
> + unsigned long min_sz_region;
> + unsigned long max_sz_region;
> + unsigned int min_nr_accesses;
> + unsigned int max_nr_accesses;
> + unsigned int min_age_region;
> + unsigned int max_age_region;
> +};
> +
> +/**
> + * struct damos - Represents a Data Access Monitoring-based Operation Scheme.
> + * @pattern: Access pattern of target regions.
> * @action: &damo_action to be applied to the target regions.
> * @quota: Control the aggressiveness of this scheme.
> * @wmarks: Watermarks for automated (in)activation of this scheme.
> @@ -230,10 +244,8 @@ struct damos_stat {
> * @list: List head for siblings.
> *
> * For each aggregation interval, DAMON finds regions which fit in the
> - * condition (&min_sz_region, &max_sz_region, &min_nr_accesses,
> - * &max_nr_accesses, &min_age_region, &max_age_region) and applies &action to
> - * those. To avoid consuming too much CPU time or IO resources for the
> - * &action, "a is used.
> + * &pattern and applies &action to those. To avoid consuming too much
> + * CPU time or IO resources for the &action, "a is used.
> *
> * To do the work only when needed, schemes can be activated for specific
> * system situations using &wmarks. If all schemes that registered to the
> @@ -248,12 +260,7 @@ struct damos_stat {
> * &action is applied.
> */
> struct damos {
> - unsigned long min_sz_region;
> - unsigned long max_sz_region;
> - unsigned int min_nr_accesses;
> - unsigned int max_nr_accesses;
> - unsigned int min_age_region;
> - unsigned int max_age_region;
> + struct damos_access_pattern pattern;
> enum damos_action action;
> struct damos_quota quota;
> struct damos_watermarks wmarks;
> @@ -501,12 +508,9 @@ void damon_destroy_region(struct damon_region *r, struct damon_target *t);
> int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges,
> unsigned int nr_ranges);
>
> -struct damos *damon_new_scheme(
> - unsigned long min_sz_region, unsigned long max_sz_region,
> - unsigned int min_nr_accesses, unsigned int max_nr_accesses,
> - unsigned int min_age_region, unsigned int max_age_region,
> - enum damos_action action, struct damos_quota *quota,
> - struct damos_watermarks *wmarks);
> +struct damos *damon_new_scheme(struct damos_access_pattern *pattern,
> + enum damos_action action, struct damos_quota *quota,
> + struct damos_watermarks *wmarks);
> void damon_add_scheme(struct damon_ctx *ctx, struct damos *s);
> void damon_destroy_scheme(struct damos *s);
>
> diff --git a/mm/damon/core.c b/mm/damon/core.c
> index 9964b9d00768..57450a0160ab 100644
> --- a/mm/damon/core.c
> +++ b/mm/damon/core.c
> @@ -230,24 +230,21 @@ int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges,
> return 0;
> }
>
> -struct damos *damon_new_scheme(
> - unsigned long min_sz_region, unsigned long max_sz_region,
> - unsigned int min_nr_accesses, unsigned int max_nr_accesses,
> - unsigned int min_age_region, unsigned int max_age_region,
> - enum damos_action action, struct damos_quota *quota,
> - struct damos_watermarks *wmarks)
> +struct damos *damon_new_scheme(struct damos_access_pattern *pattern,
> + enum damos_action action, struct damos_quota *quota,
> + struct damos_watermarks *wmarks)
> {
> struct damos *scheme;
>
> scheme = kmalloc(sizeof(*scheme), GFP_KERNEL);
> if (!scheme)
> return NULL;
> - scheme->min_sz_region = min_sz_region;
> - scheme->max_sz_region = max_sz_region;
> - scheme->min_nr_accesses = min_nr_accesses;
> - scheme->max_nr_accesses = max_nr_accesses;
> - scheme->min_age_region = min_age_region;
> - scheme->max_age_region = max_age_region;
> + scheme->pattern.min_sz_region = pattern->min_sz_region;
> + scheme->pattern.max_sz_region = pattern->max_sz_region;
> + scheme->pattern.min_nr_accesses = pattern->min_nr_accesses;
> + scheme->pattern.max_nr_accesses = pattern->max_nr_accesses;
> + scheme->pattern.min_age_region = pattern->min_age_region;
> + scheme->pattern.max_age_region = pattern->max_age_region;
> scheme->action = action;
> scheme->stat = (struct damos_stat){};
> INIT_LIST_HEAD(&scheme->list);
> @@ -666,10 +663,12 @@ static bool __damos_valid_target(struct damon_region *r, struct damos *s)
> unsigned long sz;
>
> sz = r->ar.end - r->ar.start;
> - return s->min_sz_region <= sz && sz <= s->max_sz_region &&
> - s->min_nr_accesses <= r->nr_accesses &&
> - r->nr_accesses <= s->max_nr_accesses &&
> - s->min_age_region <= r->age && r->age <= s->max_age_region;
> + return s->pattern.min_sz_region <= sz &&
> + sz <= s->pattern.max_sz_region &&
> + s->pattern.min_nr_accesses <= r->nr_accesses &&
> + r->nr_accesses <= s->pattern.max_nr_accesses &&
> + s->pattern.min_age_region <= r->age &&
> + r->age <= s->pattern.max_age_region;
> }
>
> static bool damos_valid_target(struct damon_ctx *c, struct damon_target *t,
> diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
> index 652a94deafe3..5624e1805bb3 100644
> --- a/mm/damon/dbgfs.c
> +++ b/mm/damon/dbgfs.c
> @@ -131,9 +131,9 @@ static ssize_t sprint_schemes(struct damon_ctx *c, char *buf, ssize_t len)
> damon_for_each_scheme(s, c) {
> rc = scnprintf(&buf[written], len - written,
> "%lu %lu %u %u %u %u %d %lu %lu %lu %u %u %u %d %lu %lu %lu %lu %lu %lu %lu %lu %lu\n",
> - s->min_sz_region, s->max_sz_region,
> - s->min_nr_accesses, s->max_nr_accesses,
> - s->min_age_region, s->max_age_region,
> + s->pattern.min_sz_region, s->pattern.max_sz_region,
> + s->pattern.min_nr_accesses, s->pattern.max_nr_accesses,
> + s->pattern.min_age_region, s->pattern.max_age_region,
Sorry, I prefer 80 columns rule:
https://docs.kernel.org/process/coding-style.html#breaking-long-lines-and-strings
> damos_action_to_dbgfs_scheme_action(s->action),
> s->quota.ms, s->quota.sz,
> s->quota.reset_interval,
> @@ -221,8 +221,6 @@ static struct damos **str_to_schemes(const char *str, ssize_t len,
> struct damos *scheme, **schemes;
> const int max_nr_schemes = 256;
> int pos = 0, parsed, ret;
> - unsigned long min_sz, max_sz;
> - unsigned int min_nr_a, max_nr_a, min_age, max_age;
> unsigned int action_input;
> enum damos_action action;
>
> @@ -233,13 +231,16 @@ static struct damos **str_to_schemes(const char *str, ssize_t len,
>
> *nr_schemes = 0;
> while (pos < len && *nr_schemes < max_nr_schemes) {
> + struct damos_access_pattern pattern = {};
> struct damos_quota quota = {};
> struct damos_watermarks wmarks;
>
> ret = sscanf(&str[pos],
> "%lu %lu %u %u %u %u %u %lu %lu %lu %u %u %u %u %lu %lu %lu %lu%n",
> - &min_sz, &max_sz, &min_nr_a, &max_nr_a,
> - &min_age, &max_age, &action_input, "a.ms,
> + &pattern.min_sz_region, &pattern.max_sz_region,
> + &pattern.min_nr_accesses, &pattern.max_nr_accesses,
> + &pattern.min_age_region, &pattern.max_age_region,
80 columns, again.
> + &action_input, "a.ms,
> "a.sz, "a.reset_interval,
> "a.weight_sz, "a.weight_nr_accesses,
> "a.weight_age, &wmarks.metric,
> @@ -251,7 +252,9 @@ static struct damos **str_to_schemes(const char *str, ssize_t len,
> if ((int)action < 0)
> goto fail;
>
> - if (min_sz > max_sz || min_nr_a > max_nr_a || min_age > max_age)
> + if (pattern.min_sz_region > pattern.max_sz_region ||
> + pattern.min_nr_accesses > pattern.max_nr_accesses ||
> + pattern.min_age_region > pattern.max_age_region)
> goto fail;
>
> if (wmarks.high < wmarks.mid || wmarks.high < wmarks.low ||
> @@ -259,8 +262,7 @@ static struct damos **str_to_schemes(const char *str, ssize_t len,
> goto fail;
>
> pos += parsed;
> - scheme = damon_new_scheme(min_sz, max_sz, min_nr_a, max_nr_a,
> - min_age, max_age, action, "a, &wmarks);
> + scheme = damon_new_scheme(&pattern, action, "a, &wmarks);
> if (!scheme)
> goto fail;
>
> diff --git a/mm/damon/lru_sort.c b/mm/damon/lru_sort.c
> index 9de6f00a71c5..59f6115e59de 100644
> --- a/mm/damon/lru_sort.c
> +++ b/mm/damon/lru_sort.c
> @@ -293,6 +293,17 @@ static bool get_monitoring_region(unsigned long *start, unsigned long *end)
> /* 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_access_pattern pattern = {
> + /* Find regions having PAGE_SIZE or larger size */
> + .min_sz_region = PAGE_SIZE,
> + .max_sz_region = ULONG_MAX,
> + /* and accessed for more than the threshold */
> + .min_nr_accesses = hot_thres,
> + .max_nr_accesses = UINT_MAX,
> + /* no matter its age*/
Let's add one space before closing the comment.
> + .min_age_region = 0,
> + .max_age_region = UINT_MAX,
> + };
> struct damos_watermarks wmarks = {
> .metric = DAMOS_WMARK_FREE_MEM_RATE,
> .interval = wmarks_interval,
> @@ -313,26 +324,31 @@ static struct damos *damon_lru_sort_new_hot_scheme(unsigned int hot_thres)
> .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,
> +
> + return damon_new_scheme(
> + &pattern,
> /* 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_access_pattern pattern = {
> + /* Find regions having PAGE_SIZE or larger size */
> + .min_sz_region = PAGE_SIZE,
> + .max_sz_region = ULONG_MAX,
> + /* and not accessed at all */
> + .min_nr_accesses = 0,
> + .max_nr_accesses = 0,
> + /* for min_age or more micro-seconds*/
One space before closing the comment.
> + .min_age_region = cold_thres,
> + .max_age_region = UINT_MAX,
> + };
> struct damos_watermarks wmarks = {
> .metric = DAMOS_WMARK_FREE_MEM_RATE,
> .interval = wmarks_interval,
> @@ -354,21 +370,15 @@ static struct damos *damon_lru_sort_new_cold_scheme(unsigned int cold_thres)
> .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,
> +
> + return damon_new_scheme(
> + &pattern,
> /* 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)
> diff --git a/mm/damon/reclaim.c b/mm/damon/reclaim.c
> index a7faf51b4bd4..3d78dcca1701 100644
> --- a/mm/damon/reclaim.c
> +++ b/mm/damon/reclaim.c
> @@ -264,6 +264,17 @@ static bool get_monitoring_region(unsigned long *start, unsigned long *end)
>
> static struct damos *damon_reclaim_new_scheme(void)
> {
> + struct damos_access_pattern pattern = {
> + /* Find regions having PAGE_SIZE or larger size */
> + .min_sz_region = PAGE_SIZE,
> + .max_sz_region = ULONG_MAX,
> + /* and not accessed at all */
> + .min_nr_accesses = 0,
> + .max_nr_accesses = 0,
> + /* for min_age or more micro-seconds*/
One space before closing the comment.
> + .min_age_region = min_age / aggr_interval,
> + .max_age_region = UINT_MAX,
> + };
> struct damos_watermarks wmarks = {
> .metric = DAMOS_WMARK_FREE_MEM_RATE,
> .interval = wmarks_interval,
> @@ -284,21 +295,15 @@ static struct damos *damon_reclaim_new_scheme(void)
> .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 min_age or more micro-seconds, and */
> - min_age / aggr_interval, UINT_MAX,
> +
> + return damon_new_scheme(
> + &pattern,
> /* page out those, as soon as found */
> DAMOS_PAGEOUT,
> /* under the quota. */
> "a,
> /* (De)activate this according to the watermarks. */
> &wmarks);
> -
> - return scheme;
> }
>
> static int damon_reclaim_apply_parameters(void)
> diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
> index fe6c6870cf86..012b5e9476bc 100644
> --- a/mm/damon/sysfs.c
> +++ b/mm/damon/sysfs.c
> @@ -2259,11 +2259,20 @@ static int damon_sysfs_set_targets(struct damon_ctx *ctx,
> static struct damos *damon_sysfs_mk_scheme(
> struct damon_sysfs_scheme *sysfs_scheme)
> {
> - struct damon_sysfs_access_pattern *pattern =
> + struct damon_sysfs_access_pattern *access_pattern =
> sysfs_scheme->access_pattern;
> struct damon_sysfs_quotas *sysfs_quotas = sysfs_scheme->quotas;
> struct damon_sysfs_weights *sysfs_weights = sysfs_quotas->weights;
> struct damon_sysfs_watermarks *sysfs_wmarks = sysfs_scheme->watermarks;
> +
> + struct damos_access_pattern pattern = {
> + .min_sz_region = access_pattern->sz->min,
> + .max_sz_region = access_pattern->sz->max,
> + .min_nr_accesses = access_pattern->nr_accesses->min,
> + .max_nr_accesses = access_pattern->nr_accesses->max,
> + .min_age_region = access_pattern->age->min,
> + .max_age_region = access_pattern->age->max,
> + };
> struct damos_quota quota = {
> .ms = sysfs_quotas->ms,
> .sz = sysfs_quotas->sz,
> @@ -2280,10 +2289,7 @@ static struct damos *damon_sysfs_mk_scheme(
> .low = sysfs_wmarks->low,
> };
>
> - return damon_new_scheme(pattern->sz->min, pattern->sz->max,
> - pattern->nr_accesses->min, pattern->nr_accesses->max,
> - pattern->age->min, pattern->age->max,
> - sysfs_scheme->action, "a, &wmarks);
> + return damon_new_scheme(&pattern, sysfs_scheme->action, "a, &wmarks);
80 columns?
> }
>
> static int damon_sysfs_set_schemes(struct damon_ctx *ctx,
> --
> 2.25.1
Thanks,
SJ
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