| Message ID | 20220328114144.53389-1-linmiaohe@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/memcg: remove unneeded nr_scanned | expand |
On Mon 28-03-22 19:41:44, Miaohe Lin wrote: > The local variable nr_scanned is unneeded as mem_cgroup_soft_reclaim always > does *total_scanned += nr_scanned. So we can pass total_scanned directly to > the mem_cgroup_soft_reclaim to simplify the code and save some cpu cycles > of adding nr_scanned to total_scanned. Maybe the compiler could be clever enough to generate a good code. mem_cgroup_soft_reclaim doesn't have other caller so it could be inlined. But I do agree that the change makes sense because it makes the code more consistent as mem_cgroup_soft_limit_reclaim already uses total_scanned this way. > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Acked-by: Michal Hocko <mhocko@suse.com> Thanks > --- > mm/memcontrol.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index b686ec4f42c6..79341365ec90 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -3384,7 +3384,6 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, > int loop = 0; > struct mem_cgroup_tree_per_node *mctz; > unsigned long excess; > - unsigned long nr_scanned; > > if (order > 0) > return 0; > @@ -3412,11 +3411,9 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, > if (!mz) > break; > > - nr_scanned = 0; > reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat, > - gfp_mask, &nr_scanned); > + gfp_mask, total_scanned); > nr_reclaimed += reclaimed; > - *total_scanned += nr_scanned; > spin_lock_irq(&mctz->lock); > __mem_cgroup_remove_exceeded(mz, mctz); > > -- > 2.23.0
On 2022/3/28 20:01, Michal Hocko wrote: > On Mon 28-03-22 19:41:44, Miaohe Lin wrote: >> The local variable nr_scanned is unneeded as mem_cgroup_soft_reclaim always >> does *total_scanned += nr_scanned. So we can pass total_scanned directly to >> the mem_cgroup_soft_reclaim to simplify the code and save some cpu cycles >> of adding nr_scanned to total_scanned. > > Maybe the compiler could be clever enough to generate a good code. > mem_cgroup_soft_reclaim doesn't have other caller so it could be > inlined. But I do agree that the change makes sense because it makes the > code more consistent as mem_cgroup_soft_limit_reclaim already uses > total_scanned this way. Many thanks for your comment and Acked-by tag. :) > >> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> > > Acked-by: Michal Hocko <mhocko@suse.com> > > Thanks > >> --- >> mm/memcontrol.c | 5 +---- >> 1 file changed, 1 insertion(+), 4 deletions(-) >> >> diff --git a/mm/memcontrol.c b/mm/memcontrol.c >> index b686ec4f42c6..79341365ec90 100644 >> --- a/mm/memcontrol.c >> +++ b/mm/memcontrol.c >> @@ -3384,7 +3384,6 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, >> int loop = 0; >> struct mem_cgroup_tree_per_node *mctz; >> unsigned long excess; >> - unsigned long nr_scanned; >> >> if (order > 0) >> return 0; >> @@ -3412,11 +3411,9 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, >> if (!mz) >> break; >> >> - nr_scanned = 0; >> reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat, >> - gfp_mask, &nr_scanned); >> + gfp_mask, total_scanned); >> nr_reclaimed += reclaimed; >> - *total_scanned += nr_scanned; >> spin_lock_irq(&mctz->lock); >> __mem_cgroup_remove_exceeded(mz, mctz); >> >> -- >> 2.23.0 >
On 28.03.22 13:41, Miaohe Lin wrote: > The local variable nr_scanned is unneeded as mem_cgroup_soft_reclaim always > does *total_scanned += nr_scanned. So we can pass total_scanned directly to > the mem_cgroup_soft_reclaim to simplify the code and save some cpu cycles > of adding nr_scanned to total_scanned. > > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> > --- > mm/memcontrol.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index b686ec4f42c6..79341365ec90 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -3384,7 +3384,6 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, > int loop = 0; > struct mem_cgroup_tree_per_node *mctz; > unsigned long excess; > - unsigned long nr_scanned; > > if (order > 0) > return 0; > @@ -3412,11 +3411,9 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, > if (!mz) > break; > > - nr_scanned = 0; > reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat, > - gfp_mask, &nr_scanned); > + gfp_mask, total_scanned); > nr_reclaimed += reclaimed; > - *total_scanned += nr_scanned; > spin_lock_irq(&mctz->lock); > __mem_cgroup_remove_exceeded(mz, mctz); > Reviewed-by: David Hildenbrand <david@redhat.com>
On Mon, Mar 28, 2022 at 07:41:44PM +0800, Miaohe Lin wrote: > The local variable nr_scanned is unneeded as mem_cgroup_soft_reclaim always > does *total_scanned += nr_scanned. So we can pass total_scanned directly to > the mem_cgroup_soft_reclaim to simplify the code and save some cpu cycles > of adding nr_scanned to total_scanned. > > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Thanks!
On Mon, Mar 28, 2022 at 07:41:44PM +0800, Miaohe Lin wrote: >The local variable nr_scanned is unneeded as mem_cgroup_soft_reclaim always >does *total_scanned += nr_scanned. So we can pass total_scanned directly to >the mem_cgroup_soft_reclaim to simplify the code and save some cpu cycles >of adding nr_scanned to total_scanned. > >Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> >--- Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Thanks
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b686ec4f42c6..79341365ec90 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3384,7 +3384,6 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, int loop = 0; struct mem_cgroup_tree_per_node *mctz; unsigned long excess; - unsigned long nr_scanned; if (order > 0) return 0; @@ -3412,11 +3411,9 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, if (!mz) break; - nr_scanned = 0; reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat, - gfp_mask, &nr_scanned); + gfp_mask, total_scanned); nr_reclaimed += reclaimed; - *total_scanned += nr_scanned; spin_lock_irq(&mctz->lock); __mem_cgroup_remove_exceeded(mz, mctz);
The local variable nr_scanned is unneeded as mem_cgroup_soft_reclaim always does *total_scanned += nr_scanned. So we can pass total_scanned directly to the mem_cgroup_soft_reclaim to simplify the code and save some cpu cycles of adding nr_scanned to total_scanned. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> --- mm/memcontrol.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)