* [PATCH] mm/memcontrol: make the slab calculation consistent
@ 2020-12-02 12:14 Muchun Song
2020-12-02 21:16 ` Roman Gushchin
0 siblings, 1 reply; 6+ messages in thread
From: Muchun Song @ 2020-12-02 12:14 UTC (permalink / raw)
To: hannes, mhocko, vdavydov.dev, akpm
Cc: cgroups, linux-mm, linux-kernel, Muchun Song
Although the ratio of the slab is one, we also should read the ratio
from the related memory_stats instead of hard-coding. And the local
variable of size is already the value of slab_unreclaimable. So we
do not need to read again. Simplify the code here.
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
mm/memcontrol.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9922f1510956..03a9c64560f6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1545,12 +1545,22 @@ static int __init memory_stats_init(void)
int i;
for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
+ switch (memory_stats[i].idx) {
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
- if (memory_stats[i].idx == NR_ANON_THPS ||
- memory_stats[i].idx == NR_FILE_THPS ||
- memory_stats[i].idx == NR_SHMEM_THPS)
+ case NR_ANON_THPS:
+ case NR_FILE_THPS:
+ case NR_SHMEM_THPS:
memory_stats[i].ratio = HPAGE_PMD_SIZE;
+ break;
#endif
+ case NR_SLAB_UNRECLAIMABLE_B:
+ VM_BUG_ON(i < 1);
+ VM_BUG_ON(memory_stats[i - 1].idx != NR_SLAB_RECLAIMABLE_B);
+ break;
+ default:
+ break;
+ }
+
VM_BUG_ON(!memory_stats[i].ratio);
VM_BUG_ON(memory_stats[i].idx >= MEMCG_NR_STAT);
}
@@ -1587,8 +1597,10 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
seq_buf_printf(&s, "%s %llu\n", memory_stats[i].name, size);
if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) {
- size = memcg_page_state(memcg, NR_SLAB_RECLAIMABLE_B) +
- memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE_B);
+ int idx = i - 1;
+
+ size += memcg_page_state(memcg, memory_stats[idx].idx) *
+ memory_stats[idx].ratio;
seq_buf_printf(&s, "slab %llu\n", size);
}
}
--
2.11.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] mm/memcontrol: make the slab calculation consistent
2020-12-02 12:14 [PATCH] mm/memcontrol: make the slab calculation consistent Muchun Song
@ 2020-12-02 21:16 ` Roman Gushchin
2020-12-03 2:53 ` [External] " Muchun Song
0 siblings, 1 reply; 6+ messages in thread
From: Roman Gushchin @ 2020-12-02 21:16 UTC (permalink / raw)
To: Muchun Song
Cc: hannes, mhocko, vdavydov.dev, akpm, cgroups, linux-mm, linux-kernel
On Wed, Dec 02, 2020 at 08:14:34PM +0800, Muchun Song wrote:
> Although the ratio of the slab is one, we also should read the ratio
> from the related memory_stats instead of hard-coding. And the local
> variable of size is already the value of slab_unreclaimable. So we
> do not need to read again. Simplify the code here.
>
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> ---
> mm/memcontrol.c | 22 +++++++++++++++++-----
> 1 file changed, 17 insertions(+), 5 deletions(-)
Hi Muchun!
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 9922f1510956..03a9c64560f6 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1545,12 +1545,22 @@ static int __init memory_stats_init(void)
> int i;
>
> for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
> + switch (memory_stats[i].idx) {
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> - if (memory_stats[i].idx == NR_ANON_THPS ||
> - memory_stats[i].idx == NR_FILE_THPS ||
> - memory_stats[i].idx == NR_SHMEM_THPS)
> + case NR_ANON_THPS:
> + case NR_FILE_THPS:
> + case NR_SHMEM_THPS:
> memory_stats[i].ratio = HPAGE_PMD_SIZE;
> + break;
> #endif
> + case NR_SLAB_UNRECLAIMABLE_B:
> + VM_BUG_ON(i < 1);
> + VM_BUG_ON(memory_stats[i - 1].idx != NR_SLAB_RECLAIMABLE_B);
Please, convert these to BUILD_BUG_ON(), they don't have to be runtime checks.
> + break;
> + default:
> + break;
> + }
> +
> VM_BUG_ON(!memory_stats[i].ratio);
> VM_BUG_ON(memory_stats[i].idx >= MEMCG_NR_STAT);
> }
> @@ -1587,8 +1597,10 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
> seq_buf_printf(&s, "%s %llu\n", memory_stats[i].name, size);
>
Can you, please, add a small comment here stating that we're printing
unreclaimable, reclaimable and the sum of both? It will simplify the reading of the code.
> if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) {
> - size = memcg_page_state(memcg, NR_SLAB_RECLAIMABLE_B) +
> - memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE_B);
> + int idx = i - 1;
> +
> + size += memcg_page_state(memcg, memory_stats[idx].idx) *
> + memory_stats[idx].ratio;
> seq_buf_printf(&s, "slab %llu\n", size);
> }
> }
Otherwise the patch looks good to me! Please, feel free to add
Acked-by: Roman Gushchin <guro@fb.com>
after addressing my comments.
Thanks!
> --
> 2.11.0
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [External] Re: [PATCH] mm/memcontrol: make the slab calculation consistent
2020-12-02 21:16 ` Roman Gushchin
@ 2020-12-03 2:53 ` Muchun Song
2020-12-03 3:20 ` Roman Gushchin
0 siblings, 1 reply; 6+ messages in thread
From: Muchun Song @ 2020-12-03 2:53 UTC (permalink / raw)
To: Roman Gushchin
Cc: Johannes Weiner, Michal Hocko, Vladimir Davydov, Andrew Morton,
Cgroups, Linux Memory Management List, LKML
On Thu, Dec 3, 2020 at 5:16 AM Roman Gushchin <guro@fb.com> wrote:
>
> On Wed, Dec 02, 2020 at 08:14:34PM +0800, Muchun Song wrote:
> > Although the ratio of the slab is one, we also should read the ratio
> > from the related memory_stats instead of hard-coding. And the local
> > variable of size is already the value of slab_unreclaimable. So we
> > do not need to read again. Simplify the code here.
> >
> > Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> > ---
> > mm/memcontrol.c | 22 +++++++++++++++++-----
> > 1 file changed, 17 insertions(+), 5 deletions(-)
>
> Hi Muchun!
>
> >
> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > index 9922f1510956..03a9c64560f6 100644
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -1545,12 +1545,22 @@ static int __init memory_stats_init(void)
> > int i;
> >
> > for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
> > + switch (memory_stats[i].idx) {
> > #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> > - if (memory_stats[i].idx == NR_ANON_THPS ||
> > - memory_stats[i].idx == NR_FILE_THPS ||
> > - memory_stats[i].idx == NR_SHMEM_THPS)
> > + case NR_ANON_THPS:
> > + case NR_FILE_THPS:
> > + case NR_SHMEM_THPS:
> > memory_stats[i].ratio = HPAGE_PMD_SIZE;
> > + break;
> > #endif
> > + case NR_SLAB_UNRECLAIMABLE_B:
> > + VM_BUG_ON(i < 1);
> > + VM_BUG_ON(memory_stats[i - 1].idx != NR_SLAB_RECLAIMABLE_B);
>
> Please, convert these to BUILD_BUG_ON(), they don't have to be runtime checks.
Agree. But here we cannot use BUILD_BUG_ON(). The compiler will
complain about it.
>
>
> > + break;
> > + default:
> > + break;
> > + }
> > +
> > VM_BUG_ON(!memory_stats[i].ratio);
> > VM_BUG_ON(memory_stats[i].idx >= MEMCG_NR_STAT);
> > }
> > @@ -1587,8 +1597,10 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
> > seq_buf_printf(&s, "%s %llu\n", memory_stats[i].name, size);
> >
>
> Can you, please, add a small comment here stating that we're printing
> unreclaimable, reclaimable and the sum of both? It will simplify the reading of the code.
Will do.
>
> > if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) {
> > - size = memcg_page_state(memcg, NR_SLAB_RECLAIMABLE_B) +
> > - memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE_B);
> > + int idx = i - 1;
> > +
> > + size += memcg_page_state(memcg, memory_stats[idx].idx) *
> > + memory_stats[idx].ratio;
> > seq_buf_printf(&s, "slab %llu\n", size);
> > }
> > }
>
> Otherwise the patch looks good to me! Please, feel free to add
> Acked-by: Roman Gushchin <guro@fb.com>
> after addressing my comments.
>
> Thanks!
> > --
> > 2.11.0
> >
--
Yours,
Muchun
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [External] Re: [PATCH] mm/memcontrol: make the slab calculation consistent
2020-12-03 2:53 ` [External] " Muchun Song
@ 2020-12-03 3:20 ` Roman Gushchin
2020-12-03 3:36 ` Muchun Song
0 siblings, 1 reply; 6+ messages in thread
From: Roman Gushchin @ 2020-12-03 3:20 UTC (permalink / raw)
To: Muchun Song
Cc: Johannes Weiner, Michal Hocko, Vladimir Davydov, Andrew Morton,
Cgroups, Linux Memory Management List, LKML
On Thu, Dec 03, 2020 at 10:53:33AM +0800, Muchun Song wrote:
> On Thu, Dec 3, 2020 at 5:16 AM Roman Gushchin <guro@fb.com> wrote:
> >
> > On Wed, Dec 02, 2020 at 08:14:34PM +0800, Muchun Song wrote:
> > > Although the ratio of the slab is one, we also should read the ratio
> > > from the related memory_stats instead of hard-coding. And the local
> > > variable of size is already the value of slab_unreclaimable. So we
> > > do not need to read again. Simplify the code here.
> > >
> > > Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> > > ---
> > > mm/memcontrol.c | 22 +++++++++++++++++-----
> > > 1 file changed, 17 insertions(+), 5 deletions(-)
> >
> > Hi Muchun!
> >
> > >
> > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > > index 9922f1510956..03a9c64560f6 100644
> > > --- a/mm/memcontrol.c
> > > +++ b/mm/memcontrol.c
> > > @@ -1545,12 +1545,22 @@ static int __init memory_stats_init(void)
> > > int i;
> > >
> > > for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
> > > + switch (memory_stats[i].idx) {
> > > #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> > > - if (memory_stats[i].idx == NR_ANON_THPS ||
> > > - memory_stats[i].idx == NR_FILE_THPS ||
> > > - memory_stats[i].idx == NR_SHMEM_THPS)
> > > + case NR_ANON_THPS:
> > > + case NR_FILE_THPS:
> > > + case NR_SHMEM_THPS:
> > > memory_stats[i].ratio = HPAGE_PMD_SIZE;
> > > + break;
> > > #endif
> > > + case NR_SLAB_UNRECLAIMABLE_B:
> > > + VM_BUG_ON(i < 1);
> > > + VM_BUG_ON(memory_stats[i - 1].idx != NR_SLAB_RECLAIMABLE_B);
> >
> > Please, convert these to BUILD_BUG_ON(), they don't have to be runtime checks.
>
> Agree. But here we cannot use BUILD_BUG_ON(). The compiler will
> complain about it.
We can!
We just need to change the condition. All we really need to check is that
NR_SLAB_UNRECLAIMABLE_B immediately following NR_SLAB_RECLAIMABLE_B.
Something like BUILD_BUG_ON(NR_SLAB_UNRECLAIMABLE_B != NR_SLAB_RECLAIMABLE_B + 1)
should work (completely untested).
>
> >
> >
> > > + break;
> > > + default:
> > > + break;
> > > + }
> > > +
> > > VM_BUG_ON(!memory_stats[i].ratio);
> > > VM_BUG_ON(memory_stats[i].idx >= MEMCG_NR_STAT);
> > > }
> > > @@ -1587,8 +1597,10 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
> > > seq_buf_printf(&s, "%s %llu\n", memory_stats[i].name, size);
> > >
> >
> > Can you, please, add a small comment here stating that we're printing
> > unreclaimable, reclaimable and the sum of both? It will simplify the reading of the code.
>
> Will do.
Thank you!
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [External] Re: [PATCH] mm/memcontrol: make the slab calculation consistent
2020-12-03 3:20 ` Roman Gushchin
@ 2020-12-03 3:36 ` Muchun Song
2020-12-03 3:49 ` Roman Gushchin
0 siblings, 1 reply; 6+ messages in thread
From: Muchun Song @ 2020-12-03 3:36 UTC (permalink / raw)
To: Roman Gushchin
Cc: Johannes Weiner, Michal Hocko, Vladimir Davydov, Andrew Morton,
Cgroups, Linux Memory Management List, LKML
On Thu, Dec 3, 2020 at 11:21 AM Roman Gushchin <guro@fb.com> wrote:
>
> On Thu, Dec 03, 2020 at 10:53:33AM +0800, Muchun Song wrote:
> > On Thu, Dec 3, 2020 at 5:16 AM Roman Gushchin <guro@fb.com> wrote:
> > >
> > > On Wed, Dec 02, 2020 at 08:14:34PM +0800, Muchun Song wrote:
> > > > Although the ratio of the slab is one, we also should read the ratio
> > > > from the related memory_stats instead of hard-coding. And the local
> > > > variable of size is already the value of slab_unreclaimable. So we
> > > > do not need to read again. Simplify the code here.
> > > >
> > > > Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> > > > ---
> > > > mm/memcontrol.c | 22 +++++++++++++++++-----
> > > > 1 file changed, 17 insertions(+), 5 deletions(-)
> > >
> > > Hi Muchun!
> > >
> > > >
> > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > > > index 9922f1510956..03a9c64560f6 100644
> > > > --- a/mm/memcontrol.c
> > > > +++ b/mm/memcontrol.c
> > > > @@ -1545,12 +1545,22 @@ static int __init memory_stats_init(void)
> > > > int i;
> > > >
> > > > for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
> > > > + switch (memory_stats[i].idx) {
> > > > #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> > > > - if (memory_stats[i].idx == NR_ANON_THPS ||
> > > > - memory_stats[i].idx == NR_FILE_THPS ||
> > > > - memory_stats[i].idx == NR_SHMEM_THPS)
> > > > + case NR_ANON_THPS:
> > > > + case NR_FILE_THPS:
> > > > + case NR_SHMEM_THPS:
> > > > memory_stats[i].ratio = HPAGE_PMD_SIZE;
> > > > + break;
> > > > #endif
> > > > + case NR_SLAB_UNRECLAIMABLE_B:
> > > > + VM_BUG_ON(i < 1);
> > > > + VM_BUG_ON(memory_stats[i - 1].idx != NR_SLAB_RECLAIMABLE_B);
> > >
> > > Please, convert these to BUILD_BUG_ON(), they don't have to be runtime checks.
> >
> > Agree. But here we cannot use BUILD_BUG_ON(). The compiler will
> > complain about it.
>
> We can!
>
> We just need to change the condition. All we really need to check is that
> NR_SLAB_UNRECLAIMABLE_B immediately following NR_SLAB_RECLAIMABLE_B.
But I think that we need to check that memory_stats[i] immediately following
memory_stats[j] where i is the index of NR_SLAB_UNRECLAIMABLE_B and
j is the index of NR_SLAB_RECLAIMABLE_B.
>
> Something like BUILD_BUG_ON(NR_SLAB_UNRECLAIMABLE_B != NR_SLAB_RECLAIMABLE_B + 1)
So this cannot work. Thanks.
> should work (completely untested).
>
> >
> > >
> > >
> > > > + break;
> > > > + default:
> > > > + break;
> > > > + }
> > > > +
> > > > VM_BUG_ON(!memory_stats[i].ratio);
> > > > VM_BUG_ON(memory_stats[i].idx >= MEMCG_NR_STAT);
> > > > }
> > > > @@ -1587,8 +1597,10 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
> > > > seq_buf_printf(&s, "%s %llu\n", memory_stats[i].name, size);
> > > >
> > >
> > > Can you, please, add a small comment here stating that we're printing
> > > unreclaimable, reclaimable and the sum of both? It will simplify the reading of the code.
> >
> > Will do.
>
> Thank you!
--
Yours,
Muchun
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [External] Re: [PATCH] mm/memcontrol: make the slab calculation consistent
2020-12-03 3:36 ` Muchun Song
@ 2020-12-03 3:49 ` Roman Gushchin
0 siblings, 0 replies; 6+ messages in thread
From: Roman Gushchin @ 2020-12-03 3:49 UTC (permalink / raw)
To: Muchun Song
Cc: Johannes Weiner, Michal Hocko, Vladimir Davydov, Andrew Morton,
Cgroups, Linux Memory Management List, LKML
On Thu, Dec 03, 2020 at 11:36:54AM +0800, Muchun Song wrote:
> On Thu, Dec 3, 2020 at 11:21 AM Roman Gushchin <guro@fb.com> wrote:
> >
> > On Thu, Dec 03, 2020 at 10:53:33AM +0800, Muchun Song wrote:
> > > On Thu, Dec 3, 2020 at 5:16 AM Roman Gushchin <guro@fb.com> wrote:
> > > >
> > > > On Wed, Dec 02, 2020 at 08:14:34PM +0800, Muchun Song wrote:
> > > > > Although the ratio of the slab is one, we also should read the ratio
> > > > > from the related memory_stats instead of hard-coding. And the local
> > > > > variable of size is already the value of slab_unreclaimable. So we
> > > > > do not need to read again. Simplify the code here.
> > > > >
> > > > > Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> > > > > ---
> > > > > mm/memcontrol.c | 22 +++++++++++++++++-----
> > > > > 1 file changed, 17 insertions(+), 5 deletions(-)
> > > >
> > > > Hi Muchun!
> > > >
> > > > >
> > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > > > > index 9922f1510956..03a9c64560f6 100644
> > > > > --- a/mm/memcontrol.c
> > > > > +++ b/mm/memcontrol.c
> > > > > @@ -1545,12 +1545,22 @@ static int __init memory_stats_init(void)
> > > > > int i;
> > > > >
> > > > > for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
> > > > > + switch (memory_stats[i].idx) {
> > > > > #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> > > > > - if (memory_stats[i].idx == NR_ANON_THPS ||
> > > > > - memory_stats[i].idx == NR_FILE_THPS ||
> > > > > - memory_stats[i].idx == NR_SHMEM_THPS)
> > > > > + case NR_ANON_THPS:
> > > > > + case NR_FILE_THPS:
> > > > > + case NR_SHMEM_THPS:
> > > > > memory_stats[i].ratio = HPAGE_PMD_SIZE;
> > > > > + break;
> > > > > #endif
> > > > > + case NR_SLAB_UNRECLAIMABLE_B:
> > > > > + VM_BUG_ON(i < 1);
> > > > > + VM_BUG_ON(memory_stats[i - 1].idx != NR_SLAB_RECLAIMABLE_B);
> > > >
> > > > Please, convert these to BUILD_BUG_ON(), they don't have to be runtime checks.
> > >
> > > Agree. But here we cannot use BUILD_BUG_ON(). The compiler will
> > > complain about it.
> >
> > We can!
> >
> > We just need to change the condition. All we really need to check is that
> > NR_SLAB_UNRECLAIMABLE_B immediately following NR_SLAB_RECLAIMABLE_B.
>
> But I think that we need to check that memory_stats[i] immediately following
> memory_stats[j] where i is the index of NR_SLAB_UNRECLAIMABLE_B and
> j is the index of NR_SLAB_RECLAIMABLE_B.
Ok, I see. Thanks!
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-12-03 3:50 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-12-02 12:14 [PATCH] mm/memcontrol: make the slab calculation consistent Muchun Song
2020-12-02 21:16 ` Roman Gushchin
2020-12-03 2:53 ` [External] " Muchun Song
2020-12-03 3:20 ` Roman Gushchin
2020-12-03 3:36 ` Muchun Song
2020-12-03 3:49 ` Roman Gushchin
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).