| Message ID | 20240726203110.1577216-4-roman.gushchin@linux.dev (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: memcg: page counters optimizations | expand |
On Fri, Jul 26, 2024 at 08:31:10PM GMT, Roman Gushchin wrote: > When a page_counter structure is initialized, there is no need to > use an atomic set operation to initialize the usage counter because > at this point the structure is not visible to anybody else. > ATOMIC_LONG_INIT() is what should be used in such cases. > > Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
On Fri, Jul 26, 2024 at 08:31:10PM +0000, Roman Gushchin wrote: > When a page_counter structure is initialized, there is no need to > use an atomic set operation to initialize the usage counter because > at this point the structure is not visible to anybody else. > ATOMIC_LONG_INIT() is what should be used in such cases. > > Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> > --- > include/linux/page_counter.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/page_counter.h b/include/linux/page_counter.h > index cf837d0f8ed1..5da11392b382 100644 > --- a/include/linux/page_counter.h > +++ b/include/linux/page_counter.h > @@ -53,7 +53,7 @@ static inline void page_counter_init(struct page_counter *counter, > struct page_counter *parent, > bool protection_support) > { > - atomic_long_set(&counter->usage, 0); > + counter->usage = (atomic_long_t)ATOMIC_LONG_INIT(0); Pretty cool that ATOMIC_LONG_INIT() return value needs a cast to atomic_long_t! ^_^ Acked-by: Johannes Weiner <hannes@cmpxchg.org>
On Fri, 26 Jul 2024 19:11:10 -0400 Johannes Weiner <hannes@cmpxchg.org> wrote: > On Fri, Jul 26, 2024 at 08:31:10PM +0000, Roman Gushchin wrote: > > When a page_counter structure is initialized, there is no need to > > use an atomic set operation to initialize the usage counter because > > at this point the structure is not visible to anybody else. > > ATOMIC_LONG_INIT() is what should be used in such cases. > > > > Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> > > --- > > include/linux/page_counter.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/include/linux/page_counter.h b/include/linux/page_counter.h > > index cf837d0f8ed1..5da11392b382 100644 > > --- a/include/linux/page_counter.h > > +++ b/include/linux/page_counter.h > > @@ -53,7 +53,7 @@ static inline void page_counter_init(struct page_counter *counter, > > struct page_counter *parent, > > bool protection_support) > > { > > - atomic_long_set(&counter->usage, 0); > > + counter->usage = (atomic_long_t)ATOMIC_LONG_INIT(0); > > Pretty cool that ATOMIC_LONG_INIT() return value needs a cast to > atomic_long_t! ^_^ That's because this wicked patch passed in an `int'. counter->usage = ATOMIC_LONG_INIT((atomic_long_t)0);
diff --git a/include/linux/page_counter.h b/include/linux/page_counter.h index cf837d0f8ed1..5da11392b382 100644 --- a/include/linux/page_counter.h +++ b/include/linux/page_counter.h @@ -53,7 +53,7 @@ static inline void page_counter_init(struct page_counter *counter, struct page_counter *parent, bool protection_support) { - atomic_long_set(&counter->usage, 0); + counter->usage = (atomic_long_t)ATOMIC_LONG_INIT(0); counter->max = PAGE_COUNTER_MAX; counter->parent = parent; counter->protection_support = protection_support;
When a page_counter structure is initialized, there is no need to use an atomic set operation to initialize the usage counter because at this point the structure is not visible to anybody else. ATOMIC_LONG_INIT() is what should be used in such cases. Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> --- include/linux/page_counter.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)