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Message-Id: <20220919165604.61177-1-sj@kernel.org>
Date: Mon, 19 Sep 2022 16:56:04 +0000
From: SeongJae Park <sj@...nel.org>
To: xiakaixu1987@...il.com
Cc: sj@...nel.org, akpm@...ux-foundation.org, damon@...ts.linux.dev,
linux-mm@...ck.org, linux-kernel@...r.kernel.org,
Kaixu Xia <kaixuxia@...cent.com>
Subject: Re: [PATCH] mm/damon: deduplicate damon_{reclaim,lru_sort}_apply_parameters()
Hi Kaixu,
On Mon, 19 Sep 2022 14:28:09 +0800 xiakaixu1987@...il.com wrote:
> From: Kaixu Xia <kaixuxia@...cent.com>
>
> The bodies of damon_{reclaim,lru_sort}_apply_parameters() contain
> duplicates.
Good finding!
> This commit add a common function
> damon_set_regions_from_system_ram() to removes the duplicates.
>
> Signed-off-by: Kaixu Xia <kaixuxia@...cent.com>
> ---
> include/linux/damon.h | 3 ++-
> mm/damon/core.c | 20 +++++++++++++++++++-
> mm/damon/lru_sort.c | 13 +++----------
> mm/damon/reclaim.c | 13 +++----------
> 4 files changed, 27 insertions(+), 22 deletions(-)
>
> diff --git a/include/linux/damon.h b/include/linux/damon.h
> index e7808a84675f..2fd05568ef45 100644
> --- a/include/linux/damon.h
> +++ b/include/linux/damon.h
> @@ -557,7 +557,8 @@ static inline bool damon_target_has_pid(const struct damon_ctx *ctx)
> int damon_start(struct damon_ctx **ctxs, int nr_ctxs, bool exclusive);
> int damon_stop(struct damon_ctx **ctxs, int nr_ctxs);
>
> -bool damon_find_biggest_system_ram(unsigned long *start, unsigned long *end);
> +int damon_set_regions_from_system_ram(struct damon_target *t,
> + unsigned long *start, unsigned long *end);
>
> #endif /* CONFIG_DAMON */
>
> diff --git a/mm/damon/core.c b/mm/damon/core.c
> index 9c80c6eb00c2..d967b2805a53 100644
> --- a/mm/damon/core.c
> +++ b/mm/damon/core.c
> @@ -1245,7 +1245,8 @@ static int walk_system_ram(struct resource *res, void *arg)
> * 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.
> */
> -bool damon_find_biggest_system_ram(unsigned long *start, unsigned long *end)
> +static bool damon_find_biggest_system_ram(unsigned long *start,
> + unsigned long *end)
>
> {
> struct damon_system_ram_region arg = {};
> @@ -1259,6 +1260,23 @@ bool damon_find_biggest_system_ram(unsigned long *start, unsigned long *end)
> return true;
> }
>
> +int damon_set_regions_from_system_ram(struct damon_target *t,
> + unsigned long *start, unsigned long *end)
> +{
> + struct damon_addr_range addr_range;
> +
> + if (*start > *end)
> + return -EINVAL;
> +
> + if (!*start && !*end &&
> + !damon_find_biggest_system_ram(start, end))
> + return -EINVAL;
This function sets the region as biggest system ram only if both *start and
*end are zero. The name should be changed, and it would better to have a
kernel doc comment as the behavior is not very simple. How about below?
/**
* damon_set_region_biggest_system_ram_default() - Set the region of the given
* monitoring target as requested, or biggest 'System RAM'.
* @t: The monitoring target to set the region.
* @start: The pointer to the start address of the region.
* @end: The pointer to the end address of the region.
*
* This function sets the region of @t as requested by @start and @end. If the
* values of the two pointers are pointing to are zero, however, this function
* finds the biggest 'System RAM' resource and set the region to cover the
* resource. In the latter case, this function saves the start and end address
* of the resource in @start and @end, respectively.
*
* Return: 0 on success, negative error code otherwise.
*/
> +
> + addr_range.start = *start;
> + addr_range.end = *end;
> + return damon_set_regions(t, &addr_range, 1);
> +}
> +
> static int __init damon_init(void)
> {
> damon_region_cache = KMEM_CACHE(damon_region, 0);
> diff --git a/mm/damon/lru_sort.c b/mm/damon/lru_sort.c
> index d7eb72b41cb6..0276cbec632a 100644
> --- a/mm/damon/lru_sort.c
> +++ b/mm/damon/lru_sort.c
> @@ -188,7 +188,6 @@ static struct damos *damon_lru_sort_new_cold_scheme(unsigned int cold_thres)
> static int damon_lru_sort_apply_parameters(void)
> {
> struct damos *scheme;
> - struct damon_addr_range addr_range;
> unsigned int hot_thres, cold_thres;
> int err = 0;
>
> @@ -211,15 +210,9 @@ static int damon_lru_sort_apply_parameters(void)
> return -ENOMEM;
> damon_add_scheme(ctx, scheme);
>
> - if (monitor_region_start > monitor_region_end)
> - return -EINVAL;
> - if (!monitor_region_start && !monitor_region_end &&
> - !damon_find_biggest_system_ram(&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);
> + return damon_set_regions_from_system_ram(target,
> + &monitor_region_start,
> + &monitor_region_end);
> }
>
> static int damon_lru_sort_turn(bool on)
> diff --git a/mm/damon/reclaim.c b/mm/damon/reclaim.c
> index 3d59ab11b7b3..6297e1799190 100644
> --- a/mm/damon/reclaim.c
> +++ b/mm/damon/reclaim.c
> @@ -144,7 +144,6 @@ static struct damos *damon_reclaim_new_scheme(void)
> static int damon_reclaim_apply_parameters(void)
> {
> struct damos *scheme;
> - struct damon_addr_range addr_range;
> int err = 0;
>
> err = damon_set_attrs(ctx, &damon_reclaim_mon_attrs);
> @@ -157,15 +156,9 @@ static int damon_reclaim_apply_parameters(void)
> return -ENOMEM;
> damon_set_schemes(ctx, &scheme, 1);
>
> - if (monitor_region_start > monitor_region_end)
> - return -EINVAL;
> - if (!monitor_region_start && !monitor_region_end &&
> - !damon_find_biggest_system_ram(&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);
> + return damon_set_regions_from_system_ram(target,
> + &monitor_region_start,
> + &monitor_region_end);
> }
>
> static int damon_reclaim_turn(bool on)
> --
> 2.27.0
>
Thanks,
SJ
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