On Mon, Oct 19, 2020 at 8:31 PM Michal Hocko <[email protected]> wrote:
>
> On Mon 19-10-20 18:15:20, Muchun Song wrote:
> > For the exclusive reference page, the non-atomic operations is enough,
> > so replace them to non-atomic operations.
>
> I do expect you do not see any difference in runtime and this is mostly
> driven by the code reading, right? Being explicit about this in the code
> would be preferred.
Yeah, just code reading.And the set_bit and __set_bit is actually different
on some architectures. Thanks.
>
> No objection to the change.
>
> > Signed-off-by: Muchun Song <[email protected]>
>
> With an improved changelog
> Acked-by: Michal Hocko <[email protected]>
>
> > ---
> > include/linux/page-flags.h | 2 ++
> > mm/memory.c | 4 ++--
> > 2 files changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
> > index fbbb841a9346..ec039dde5e4b 100644
> > --- a/include/linux/page-flags.h
> > +++ b/include/linux/page-flags.h
> > @@ -401,6 +401,8 @@ static __always_inline int PageSwapCache(struct page *page)
> > }
> > SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
> > CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
> > +__SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
> > +__CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
> > #else
> > PAGEFLAG_FALSE(SwapCache)
> > #endif
> > diff --git a/mm/memory.c b/mm/memory.c
> > index 2d267ef6621a..02dd62da26e0 100644
> > --- a/mm/memory.c
> > +++ b/mm/memory.c
> > @@ -3128,10 +3128,10 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
> > set_page_private(page, entry.val);
> >
> > /* Tell memcg to use swap ownership records */
> > - SetPageSwapCache(page);
> > + __SetPageSwapCache(page);
> > err = mem_cgroup_charge(page, vma->vm_mm,
> > GFP_KERNEL);
> > - ClearPageSwapCache(page);
> > + __ClearPageSwapCache(page);
> > if (err) {
> > ret = VM_FAULT_OOM;
> > goto out_page;
> > --
> > 2.20.1
> >
>
> --
> Michal Hocko
> SUSE Labs
--
Yours,
Muchun
On 10/19/20 10:58 PM, Muchun Song wrote:
> On Mon, Oct 19, 2020 at 8:31 PM Michal Hocko <[email protected]> wrote:
>>
>> On Mon 19-10-20 18:15:20, Muchun Song wrote:
>>> For the exclusive reference page, the non-atomic operations is enough,
>>> so replace them to non-atomic operations.
>>
>> I do expect you do not see any difference in runtime and this is mostly
>> driven by the code reading, right? Being explicit about this in the code
>> would be preferred.
>
> Yeah, just code reading.And the set_bit and __set_bit is actually different
> on some architectures. Thanks.
>
>>
>> No objection to the change.
>>
>>> Signed-off-by: Muchun Song <[email protected]>
>>
>> With an improved changelog
>> Acked-by: Michal Hocko <[email protected]>
>>
>>> ---
>>> include/linux/page-flags.h | 2 ++
>>> mm/memory.c | 4 ++--
>>> 2 files changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
>>> index fbbb841a9346..ec039dde5e4b 100644
>>> --- a/include/linux/page-flags.h
>>> +++ b/include/linux/page-flags.h
>>> @@ -401,6 +401,8 @@ static __always_inline int PageSwapCache(struct page *page)
>>> }
>>> SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
>>> CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
>>> +__SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
>>> +__CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
>>> #else
>>> PAGEFLAG_FALSE(SwapCache)
>>> #endif
>>> diff --git a/mm/memory.c b/mm/memory.c
>>> index 2d267ef6621a..02dd62da26e0 100644
>>> --- a/mm/memory.c
>>> +++ b/mm/memory.c
>>> @@ -3128,10 +3128,10 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
>>> set_page_private(page, entry.val);
>>>
>>> /* Tell memcg to use swap ownership records */
>>> - SetPageSwapCache(page);
>>> + __SetPageSwapCache(page);
Good evening, Muchun. I found there are still some places could be
replaced with __SetPageSwapCache（）. Such as shmem_replace_page（）, why
PG_locked has been set before SetPageSwapCache（） is involved.
Would you please to check the rest places? :)
Thanks
Acked-by: Yanfei Xu <[email protected]>
>>> err = mem_cgroup_charge(page, vma->vm_mm,
>>> GFP_KERNEL);
>>> - ClearPageSwapCache(page);
>>> + __ClearPageSwapCache(page);
>>> if (err) {
>>> ret = VM_FAULT_OOM;
>>> goto out_page;
>>> --
>>> 2.20.1
>>>
>>
>> --
>> Michal Hocko
>> SUSE Labs
>
>
>
On Tue, Oct 20, 2020 at 7:51 PM Xu, Yanfei <[email protected]> wrote:
>
>
>
> On 10/19/20 10:58 PM, Muchun Song wrote:
> > On Mon, Oct 19, 2020 at 8:31 PM Michal Hocko <[email protected]> wrote:
> >>
> >> On Mon 19-10-20 18:15:20, Muchun Song wrote:
> >>> For the exclusive reference page, the non-atomic operations is enough,
> >>> so replace them to non-atomic operations.
> >>
> >> I do expect you do not see any difference in runtime and this is mostly
> >> driven by the code reading, right? Being explicit about this in the code
> >> would be preferred.
> >
> > Yeah, just code reading.And the set_bit and __set_bit is actually different
> > on some architectures. Thanks.
> >
> >>
> >> No objection to the change.
> >>
> >>> Signed-off-by: Muchun Song <[email protected]>
> >>
> >> With an improved changelog
> >> Acked-by: Michal Hocko <[email protected]>
> >>
> >>> ---
> >>> include/linux/page-flags.h | 2 ++
> >>> mm/memory.c | 4 ++--
> >>> 2 files changed, 4 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
> >>> index fbbb841a9346..ec039dde5e4b 100644
> >>> --- a/include/linux/page-flags.h
> >>> +++ b/include/linux/page-flags.h
> >>> @@ -401,6 +401,8 @@ static __always_inline int PageSwapCache(struct page *page)
> >>> }
> >>> SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
> >>> CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
> >>> +__SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
> >>> +__CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
> >>> #else
> >>> PAGEFLAG_FALSE(SwapCache)
> >>> #endif
> >>> diff --git a/mm/memory.c b/mm/memory.c
> >>> index 2d267ef6621a..02dd62da26e0 100644
> >>> --- a/mm/memory.c
> >>> +++ b/mm/memory.c
> >>> @@ -3128,10 +3128,10 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
> >>> set_page_private(page, entry.val);
> >>>
> >>> /* Tell memcg to use swap ownership records */
> >>> - SetPageSwapCache(page);
> >>> + __SetPageSwapCache(page);
>
> Good evening, Muchun. I found there are still some places could be
> replaced with __SetPageSwapCache（）. Such as shmem_replace_page（）, why
Yeah, thanks for your suggestion.
> PG_locked has been set before SetPageSwapCache（） is involved.
In this case, It doesn't matter whether PG_locked is set before
SetPageSwapCache.
>
> Would you please to check the rest places? :)
Ok, I'll take a look. Thanks.
>
> Thanks
>
> Acked-by: Yanfei Xu <[email protected]>
>
> >>> err = mem_cgroup_charge(page, vma->vm_mm,
> >>> GFP_KERNEL);
> >>> - ClearPageSwapCache(page);
> >>> + __ClearPageSwapCache(page);
> >>> if (err) {
> >>> ret = VM_FAULT_OOM;
> >>> goto out_page;
> >>> --
> >>> 2.20.1
> >>>
> >>
> >> --
> >> Michal Hocko
> >> SUSE Labs
> >
> >
> >
--
Yours,
Muchun
On 10/20/20 9:08 PM, Muchun Song wrote:
> On Tue, Oct 20, 2020 at 7:51 PM Xu, Yanfei <[email protected]> wrote:
>>
>>
>>
>> On 10/19/20 10:58 PM, Muchun Song wrote:
>>> On Mon, Oct 19, 2020 at 8:31 PM Michal Hocko <[email protected]> wrote:
>>>>
>>>> On Mon 19-10-20 18:15:20, Muchun Song wrote:
>>>>> For the exclusive reference page, the non-atomic operations is enough,
>>>>> so replace them to non-atomic operations.
>>>>
>>>> I do expect you do not see any difference in runtime and this is mostly
>>>> driven by the code reading, right? Being explicit about this in the code
>>>> would be preferred.
>>>
>>> Yeah, just code reading.And the set_bit and __set_bit is actually different
>>> on some architectures. Thanks.
>>>
>>>>
>>>> No objection to the change.
>>>>
>>>>> Signed-off-by: Muchun Song <[email protected]>
>>>>
>>>> With an improved changelog
>>>> Acked-by: Michal Hocko <[email protected]>
>>>>
>>>>> ---
>>>>> include/linux/page-flags.h | 2 ++
>>>>> mm/memory.c | 4 ++--
>>>>> 2 files changed, 4 insertions(+), 2 deletions(-)
>>>>>
>>>>> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
>>>>> index fbbb841a9346..ec039dde5e4b 100644
>>>>> --- a/include/linux/page-flags.h
>>>>> +++ b/include/linux/page-flags.h
>>>>> @@ -401,6 +401,8 @@ static __always_inline int PageSwapCache(struct page *page)
>>>>> }
>>>>> SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
>>>>> CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
>>>>> +__SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
>>>>> +__CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
>>>>> #else
>>>>> PAGEFLAG_FALSE(SwapCache)
>>>>> #endif
>>>>> diff --git a/mm/memory.c b/mm/memory.c
>>>>> index 2d267ef6621a..02dd62da26e0 100644
>>>>> --- a/mm/memory.c
>>>>> +++ b/mm/memory.c
>>>>> @@ -3128,10 +3128,10 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
>>>>> set_page_private(page, entry.val);
>>>>>
>>>>> /* Tell memcg to use swap ownership records */
>>>>> - SetPageSwapCache(page);
>>>>> + __SetPageSwapCache(page);
>>
>> Good evening, Muchun. I found there are still some places could be
>> replaced with __SetPageSwapCache（）. Such as shmem_replace_page（）, why
>
> Yeah, thanks for your suggestion.
>
>> PG_locked has been set before SetPageSwapCache（） is involved.
>
> In this case, It doesn't matter whether PG_locked is set before
> SetPageSwapCache.
>
Sorry for this mistake. PG_locked is used for disk I/O.
>>
>> Would you please to check the rest places? :)
>
> Ok, I'll take a look. Thanks.
>
>>
>> Thanks
>>
>> Acked-by: Yanfei Xu <[email protected]>
>>
>>>>> err = mem_cgroup_charge(page, vma->vm_mm,
>>>>> GFP_KERNEL);
>>>>> - ClearPageSwapCache(page);
>>>>> + __ClearPageSwapCache(page);
>>>>> if (err) {
>>>>> ret = VM_FAULT_OOM;
>>>>> goto out_page;
>>>>> --
>>>>> 2.20.1
>>>>>
>>>>
>>>> --
>>>> Michal Hocko
>>>> SUSE Labs
>>>
>>>
>>>
>
>
>
> --
> Yours,
> Muchun
>