| Message ID | 20240405060858.2818-2-honggyu.kim@sk.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | DAMON based tiered memory management for CXL memory | expand |
On Fri, 5 Apr 2024 15:08:50 +0900 Honggyu Kim <honggyu.kim@sk.com> wrote: > This is a preparation patch that introduces migration modes. > > The damon_pa_pageout is renamed to damon_pa_migrate and it receives an > extra argument for migration_mode. I personally think keeping damon_pa_pageout() as is and adding a new function (damon_pa_migrate()) with some duplicated code is also ok, but this approach also looks fine to me. So I have no strong opinion here, but just letting you know I would have no objection at both approaches. > > No functional changes applied. > > Signed-off-by: Honggyu Kim <honggyu.kim@sk.com> > --- > mm/damon/paddr.c | 18 +++++++++++++++--- > 1 file changed, 15 insertions(+), 3 deletions(-) > > diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c > index 081e2a325778..277a1c4d833c 100644 > --- a/mm/damon/paddr.c > +++ b/mm/damon/paddr.c > @@ -224,7 +224,12 @@ static bool damos_pa_filter_out(struct damos *scheme, struct folio *folio) > return false; > } > > -static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s) > +enum migration_mode { > + MIG_PAGEOUT, > +}; To avoid name conflicts, what about renaming to 'damos_migration_mode' and 'DAMOS_MIG_PAGEOUT'? > + > +static unsigned long damon_pa_migrate(struct damon_region *r, struct damos *s, > + enum migration_mode mm) My poor brain has a bit confused with the name. What about calling it 'mode'? > { > unsigned long addr, applied; > LIST_HEAD(folio_list); > @@ -249,7 +254,14 @@ static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s) > put_folio: > folio_put(folio); > } > - applied = reclaim_pages(&folio_list); > + switch (mm) { > + case MIG_PAGEOUT: > + applied = reclaim_pages(&folio_list); > + break; > + default: > + /* Unexpected migration mode. */ > + return 0; > + } > cond_resched(); > return applied * PAGE_SIZE; > } > @@ -297,7 +309,7 @@ static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx, > { > switch (scheme->action) { > case DAMOS_PAGEOUT: > - return damon_pa_pageout(r, scheme); > + return damon_pa_migrate(r, scheme, MIG_PAGEOUT); > case DAMOS_LRU_PRIO: > return damon_pa_mark_accessed(r, scheme); > case DAMOS_LRU_DEPRIO: > -- > 2.34.1 Thanks, SJ
On Fri, 5 Apr 2024 12:19:07 -0700 SeongJae Park <sj@kernel.org> wrote: > On Fri, 5 Apr 2024 15:08:50 +0900 Honggyu Kim <honggyu.kim@sk.com> wrote: > > > This is a preparation patch that introduces migration modes. > > > > The damon_pa_pageout is renamed to damon_pa_migrate and it receives an > > extra argument for migration_mode. > > I personally think keeping damon_pa_pageout() as is and adding a new function > (damon_pa_migrate()) with some duplicated code is also ok, but this approach > also looks fine to me. So I have no strong opinion here, but just letting you > know I would have no objection at both approaches. Meanwhile, we added one more logic in damon_pa_pageout() for doing page idleness double check on its own[1]. It makes reusing damon_pa_pageout() for multiple reason a bit complex. I think the complexity added a problem in this patch that I also missed before due to the complexity. Show below comment in line. Hence now I think it would be better to do the suggested way. If we use the approach, this patch is no more necessary, and therefore can be dropped. [1] https://lore.kernel.org/20240426195247.100306-1-sj@kernel.org Thanks, SJ [...] > > > > > No functional changes applied. > > > > Signed-off-by: Honggyu Kim <honggyu.kim@sk.com> > > --- > > mm/damon/paddr.c | 18 +++++++++++++++--- > > 1 file changed, 15 insertions(+), 3 deletions(-) > > > > diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c > > index 081e2a325778..277a1c4d833c 100644 > > --- a/mm/damon/paddr.c > > +++ b/mm/damon/paddr.c > > @@ -224,7 +224,12 @@ static bool damos_pa_filter_out(struct damos *scheme, struct folio *folio) > > return false; > > } > > > > -static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s) > > +enum migration_mode { > > + MIG_PAGEOUT, > > +}; > > To avoid name conflicts, what about renaming to 'damos_migration_mode' and > 'DAMOS_MIG_PAGEOUT'? > > > + > > +static unsigned long damon_pa_migrate(struct damon_region *r, struct damos *s, > > + enum migration_mode mm) > > My poor brain has a bit confused with the name. What about calling it 'mode'? > > > { > > unsigned long addr, applied; > > LIST_HEAD(folio_list); > > @@ -249,7 +254,14 @@ static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s) Before this line, damon_pa_pageout() calls folio_clear_referenced() and folio_test_clear_young() for the folio, because this is pageout code. Changed function, damon_pa_migrate() is not only for cold pages but general migrations. Hence it should also be handled based on the migration mode, but not handled. I think this problem came from the increased complexity of this function. Hence I think it is better to keep damon_pa_pageout() as is and adding a new function for migration. Thanks, SJ [...]
On Sat, 11 May 2024 13:16:17 -0700 SeongJae Park <sj@kernel.org> wrote: > On Fri, 5 Apr 2024 12:19:07 -0700 SeongJae Park <sj@kernel.org> wrote: > > > On Fri, 5 Apr 2024 15:08:50 +0900 Honggyu Kim <honggyu.kim@sk.com> wrote: > > > > > This is a preparation patch that introduces migration modes. > > > > > > The damon_pa_pageout is renamed to damon_pa_migrate and it receives an > > > extra argument for migration_mode. > > > > I personally think keeping damon_pa_pageout() as is and adding a new function > > (damon_pa_migrate()) with some duplicated code is also ok, but this approach > > also looks fine to me. So I have no strong opinion here, but just letting you > > know I would have no objection at both approaches. > > Meanwhile, we added one more logic in damon_pa_pageout() for doing page > idleness double check on its own[1]. It makes reusing damon_pa_pageout() for > multiple reason a bit complex. I think the complexity added a problem in this > patch that I also missed before due to the complexity. Show below comment in > line. Hence now I think it would be better to do the suggested way. > > If we use the approach, this patch is no more necessary, and therefore can be > dropped. > > [1] https://lore.kernel.org/20240426195247.100306-1-sj@kernel.org I updated this patchset to address comments on this thread, and posted it as RFC patchset v4 on behalf of Honggyu under his approval: https://lore.kernel.org/20240512175447.75943-1-sj@kernel.org Thanks, SJ [...]
diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c index 081e2a325778..277a1c4d833c 100644 --- a/mm/damon/paddr.c +++ b/mm/damon/paddr.c @@ -224,7 +224,12 @@ static bool damos_pa_filter_out(struct damos *scheme, struct folio *folio) return false; } -static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s) +enum migration_mode { + MIG_PAGEOUT, +}; + +static unsigned long damon_pa_migrate(struct damon_region *r, struct damos *s, + enum migration_mode mm) { unsigned long addr, applied; LIST_HEAD(folio_list); @@ -249,7 +254,14 @@ static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s) put_folio: folio_put(folio); } - applied = reclaim_pages(&folio_list); + switch (mm) { + case MIG_PAGEOUT: + applied = reclaim_pages(&folio_list); + break; + default: + /* Unexpected migration mode. */ + return 0; + } cond_resched(); return applied * PAGE_SIZE; } @@ -297,7 +309,7 @@ static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx, { switch (scheme->action) { case DAMOS_PAGEOUT: - return damon_pa_pageout(r, scheme); + return damon_pa_migrate(r, scheme, MIG_PAGEOUT); case DAMOS_LRU_PRIO: return damon_pa_mark_accessed(r, scheme); case DAMOS_LRU_DEPRIO:
This is a preparation patch that introduces migration modes. The damon_pa_pageout is renamed to damon_pa_migrate and it receives an extra argument for migration_mode. No functional changes applied. Signed-off-by: Honggyu Kim <honggyu.kim@sk.com> --- mm/damon/paddr.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-)