Hi Xin,
On Wed, 14 Sep 2022 19:38:59 +0800 Xin Hao <xhao@xxxxxxxxxxxxxxxxx> wrote:
In damon_lru_sort_new_hot_scheme() and damon_lru_sort_new_cold_scheme(),
they have so much in common, so we can combine them into a single
function, and we just need to distinguish their differences.
Thank you again for patiently waiting for my changes and reworking on this!
Signed-off-by: Xin Hao <xhao@xxxxxxxxxxxxxxxxx>
---
mm/damon/lru_sort.c | 57 ++++++++++++++++++++++-----------------------
1 file changed, 28 insertions(+), 29 deletions(-)
diff --git a/mm/damon/lru_sort.c b/mm/damon/lru_sort.c
index 07a0908963fd..2eac907e866d 100644
--- a/mm/damon/lru_sort.c
+++ b/mm/damon/lru_sort.c
@@ -135,17 +135,40 @@ DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_lru_sort_cold_stat,
static struct damon_ctx *ctx;
static struct damon_target *target;
-static struct damos *damon_lru_sort_new_scheme(
- struct damos_access_pattern *pattern, enum damos_action action)
+static struct damos *damon_lru_sort_new_scheme(unsigned int thres,
+ enum damos_action action)
{
+ 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 */
This comment would be better to be written again?
+ .min_nr_accesses = 0,
+ .max_nr_accesses = 0,
If we're gonna set above two fields anyway later, we could simply remove above
three lines.
+ /* no matter its age */
+ .min_age_region = 0,
+ .max_age_region = UINT_MAX,
+ };
struct damos_quota quota = damon_lru_sort_quota;
/* Use half of total quota for hot/cold pages sorting */
quota.ms = quota.ms / 2;
+ switch (action) {
+ case DAMOS_LRU_PRIO:
+ pattern.min_nr_accesses = thres;
+ pattern.max_nr_accesses = UINT_MAX;
+ break;
+ case DAMOS_LRU_DEPRIO:
+ pattern.min_age_region = thres;
+ break;
+ default:
+ return NULL;
+ }
+
This switch-case makes me wondering if the 'default' case really possible case.
I think it would be clearer to set these from caller.
IMHO, it might be clearer and shorter to define a static global 'struct
damos_access_pattern' stub variable, and make the
damon_lru_sort_new_{hot,cold}_scheme() copies it to their local variable,
update the relevant fields, and pass that to 'damon_new_scheme()'. What do you
think?
return damon_new_scheme(
/* find the pattern, and */
- pattern,
+ &pattern,
/* (de)prioritize on LRU-lists */
action,
/* under the quota. */
@@ -157,37 +180,13 @@ static struct damos *damon_lru_sort_new_scheme(
/* 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 */
- .min_age_region = 0,
- .max_age_region = UINT_MAX,
- };
-
- return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_PRIO);
+ return damon_lru_sort_new_scheme(hot_thres, DAMOS_LRU_PRIO);
If we follow what I suggested above, we could make this like below:
struct damos_access_pattern pattern = damon_lru_sort_stub_access_pattern;
pattern.min_nr_accesses = hot_thres;
return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_PRIO);
