* [PATCH] mm/swap: Fix release_pages() when releasing devmap pages
@ 2019-05-23 22:37 ira.weiny
2019-05-24 1:05 ` John Hubbard
2019-05-24 3:58 ` Dan Williams
0 siblings, 2 replies; 6+ messages in thread
From: ira.weiny @ 2019-05-23 22:37 UTC (permalink / raw)
To: Andrew Morton
Cc: Michal Hocko, linux-mm, linux-kernel, John Hubbard, Ira Weiny,
Jérôme Glisse, Dan Williams
From: Ira Weiny <ira.weiny@intel.com>
Device pages can be more than type MEMORY_DEVICE_PUBLIC.
Handle all device pages within release_pages()
This was found via code inspection while determining if release_pages()
and the new put_user_pages() could be interchangeable.
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
---
mm/swap.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/mm/swap.c b/mm/swap.c
index 3a75722e68a9..d1e8122568d0 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -739,15 +739,14 @@ void release_pages(struct page **pages, int nr)
if (is_huge_zero_page(page))
continue;
- /* Device public page can not be huge page */
- if (is_device_public_page(page)) {
+ if (is_zone_device_page(page)) {
if (locked_pgdat) {
spin_unlock_irqrestore(&locked_pgdat->lru_lock,
flags);
locked_pgdat = NULL;
}
- put_devmap_managed_page(page);
- continue;
+ if (put_devmap_managed_page(page))
+ continue;
}
page = compound_head(page);
--
2.20.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] mm/swap: Fix release_pages() when releasing devmap pages
2019-05-23 22:37 [PATCH] mm/swap: Fix release_pages() when releasing devmap pages ira.weiny
@ 2019-05-24 1:05 ` John Hubbard
2019-05-24 3:58 ` Dan Williams
1 sibling, 0 replies; 6+ messages in thread
From: John Hubbard @ 2019-05-24 1:05 UTC (permalink / raw)
To: ira.weiny, Andrew Morton
Cc: Michal Hocko, linux-mm, linux-kernel, Jérôme Glisse,
Dan Williams
On 5/23/19 3:37 PM, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
>
> Device pages can be more than type MEMORY_DEVICE_PUBLIC.
>
> Handle all device pages within release_pages()
>
> This was found via code inspection while determining if release_pages()
> and the new put_user_pages() could be interchangeable.
>
> Cc: Jérôme Glisse <jglisse@redhat.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> ---
> mm/swap.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/mm/swap.c b/mm/swap.c
> index 3a75722e68a9..d1e8122568d0 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -739,15 +739,14 @@ void release_pages(struct page **pages, int nr)
> if (is_huge_zero_page(page))
> continue;
>
> - /* Device public page can not be huge page */
> - if (is_device_public_page(page)) {
> + if (is_zone_device_page(page)) {
> if (locked_pgdat) {
> spin_unlock_irqrestore(&locked_pgdat->lru_lock,
> flags);
> locked_pgdat = NULL;
> }
> - put_devmap_managed_page(page);
> - continue;
> + if (put_devmap_managed_page(page))
> + continue;
> }
>
> page = compound_head(page);
>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
thanks,
--
John Hubbard
NVIDIA
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] mm/swap: Fix release_pages() when releasing devmap pages
2019-05-23 22:37 [PATCH] mm/swap: Fix release_pages() when releasing devmap pages ira.weiny
2019-05-24 1:05 ` John Hubbard
@ 2019-05-24 3:58 ` Dan Williams
2019-05-24 15:36 ` Ira Weiny
2019-05-24 21:03 ` Dan Williams
1 sibling, 2 replies; 6+ messages in thread
From: Dan Williams @ 2019-05-24 3:58 UTC (permalink / raw)
To: Weiny, Ira
Cc: Andrew Morton, Michal Hocko, Linux MM, Linux Kernel Mailing List,
John Hubbard, Jérôme Glisse
On Thu, May 23, 2019 at 3:37 PM <ira.weiny@intel.com> wrote:
>
> From: Ira Weiny <ira.weiny@intel.com>
>
> Device pages can be more than type MEMORY_DEVICE_PUBLIC.
>
> Handle all device pages within release_pages()
>
> This was found via code inspection while determining if release_pages()
> and the new put_user_pages() could be interchangeable.
>
> Cc: Jérôme Glisse <jglisse@redhat.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> ---
> mm/swap.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/mm/swap.c b/mm/swap.c
> index 3a75722e68a9..d1e8122568d0 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -739,15 +739,14 @@ void release_pages(struct page **pages, int nr)
> if (is_huge_zero_page(page))
> continue;
>
> - /* Device public page can not be huge page */
> - if (is_device_public_page(page)) {
> + if (is_zone_device_page(page)) {
> if (locked_pgdat) {
> spin_unlock_irqrestore(&locked_pgdat->lru_lock,
> flags);
> locked_pgdat = NULL;
> }
> - put_devmap_managed_page(page);
> - continue;
> + if (put_devmap_managed_page(page))
This "shouldn't" fail, and if it does the code that follows might get
confused by a ZONE_DEVICE page. If anything I would make this a
WARN_ON_ONCE(!put_devmap_managed_page(page)), but always continue
unconditionally.
Other than that you can add:
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] mm/swap: Fix release_pages() when releasing devmap pages
2019-05-24 3:58 ` Dan Williams
@ 2019-05-24 15:36 ` Ira Weiny
2019-05-24 15:48 ` Dan Williams
2019-05-24 21:03 ` Dan Williams
1 sibling, 1 reply; 6+ messages in thread
From: Ira Weiny @ 2019-05-24 15:36 UTC (permalink / raw)
To: Dan Williams
Cc: Andrew Morton, Michal Hocko, Linux MM, Linux Kernel Mailing List,
John Hubbard, Jérôme Glisse
On Thu, May 23, 2019 at 08:58:12PM -0700, Dan Williams wrote:
> On Thu, May 23, 2019 at 3:37 PM <ira.weiny@intel.com> wrote:
> >
> > From: Ira Weiny <ira.weiny@intel.com>
> >
> > Device pages can be more than type MEMORY_DEVICE_PUBLIC.
> >
> > Handle all device pages within release_pages()
> >
> > This was found via code inspection while determining if release_pages()
> > and the new put_user_pages() could be interchangeable.
> >
> > Cc: Jérôme Glisse <jglisse@redhat.com>
> > Cc: Dan Williams <dan.j.williams@intel.com>
> > Cc: Michal Hocko <mhocko@suse.com>
> > Cc: John Hubbard <jhubbard@nvidia.com>
> > Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> > ---
> > mm/swap.c | 7 +++----
> > 1 file changed, 3 insertions(+), 4 deletions(-)
> >
> > diff --git a/mm/swap.c b/mm/swap.c
> > index 3a75722e68a9..d1e8122568d0 100644
> > --- a/mm/swap.c
> > +++ b/mm/swap.c
> > @@ -739,15 +739,14 @@ void release_pages(struct page **pages, int nr)
> > if (is_huge_zero_page(page))
> > continue;
> >
> > - /* Device public page can not be huge page */
> > - if (is_device_public_page(page)) {
> > + if (is_zone_device_page(page)) {
> > if (locked_pgdat) {
> > spin_unlock_irqrestore(&locked_pgdat->lru_lock,
> > flags);
> > locked_pgdat = NULL;
> > }
> > - put_devmap_managed_page(page);
> > - continue;
> > + if (put_devmap_managed_page(page))
>
> This "shouldn't" fail, and if it does the code that follows might get
I agree it shouldn't based on the check. However...
> confused by a ZONE_DEVICE page. If anything I would make this a
> WARN_ON_ONCE(!put_devmap_managed_page(page)), but always continue
> unconditionally.
I was trying to follow the pattern from put_page() Where if fails it indicated
it was not a devmap page and so "regular" processing should continue.
Since I'm unsure I'll just ask what does this check do?
if (!static_branch_unlikely(&devmap_managed_key))
return false;
... In put_devmap_managed_page()?
>
> Other than that you can add:
>
> Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Thanks v2 to follow.
Ira
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] mm/swap: Fix release_pages() when releasing devmap pages
2019-05-24 15:36 ` Ira Weiny
@ 2019-05-24 15:48 ` Dan Williams
0 siblings, 0 replies; 6+ messages in thread
From: Dan Williams @ 2019-05-24 15:48 UTC (permalink / raw)
To: Ira Weiny
Cc: Andrew Morton, Michal Hocko, Linux MM, Linux Kernel Mailing List,
John Hubbard, Jérôme Glisse
On Fri, May 24, 2019 at 8:35 AM Ira Weiny <ira.weiny@intel.com> wrote:
>
> On Thu, May 23, 2019 at 08:58:12PM -0700, Dan Williams wrote:
> > On Thu, May 23, 2019 at 3:37 PM <ira.weiny@intel.com> wrote:
> > >
> > > From: Ira Weiny <ira.weiny@intel.com>
> > >
> > > Device pages can be more than type MEMORY_DEVICE_PUBLIC.
> > >
> > > Handle all device pages within release_pages()
> > >
> > > This was found via code inspection while determining if release_pages()
> > > and the new put_user_pages() could be interchangeable.
> > >
> > > Cc: Jérôme Glisse <jglisse@redhat.com>
> > > Cc: Dan Williams <dan.j.williams@intel.com>
> > > Cc: Michal Hocko <mhocko@suse.com>
> > > Cc: John Hubbard <jhubbard@nvidia.com>
> > > Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> > > ---
> > > mm/swap.c | 7 +++----
> > > 1 file changed, 3 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/mm/swap.c b/mm/swap.c
> > > index 3a75722e68a9..d1e8122568d0 100644
> > > --- a/mm/swap.c
> > > +++ b/mm/swap.c
> > > @@ -739,15 +739,14 @@ void release_pages(struct page **pages, int nr)
> > > if (is_huge_zero_page(page))
> > > continue;
> > >
> > > - /* Device public page can not be huge page */
> > > - if (is_device_public_page(page)) {
> > > + if (is_zone_device_page(page)) {
> > > if (locked_pgdat) {
> > > spin_unlock_irqrestore(&locked_pgdat->lru_lock,
> > > flags);
> > > locked_pgdat = NULL;
> > > }
> > > - put_devmap_managed_page(page);
> > > - continue;
> > > + if (put_devmap_managed_page(page))
> >
> > This "shouldn't" fail, and if it does the code that follows might get
>
> I agree it shouldn't based on the check. However...
>
> > confused by a ZONE_DEVICE page. If anything I would make this a
> > WARN_ON_ONCE(!put_devmap_managed_page(page)), but always continue
> > unconditionally.
>
> I was trying to follow the pattern from put_page() Where if fails it indicated
> it was not a devmap page and so "regular" processing should continue.
In this case that regular continuation already happened by not taking
the if (is_zone_device_page(page)) branch
>
> Since I'm unsure I'll just ask what does this check do?
>
> if (!static_branch_unlikely(&devmap_managed_key))
> return false;
That attempts to skip the overhead imposed by device-pages, i.e.
->page_free() callback and other extras, if there are no device-page
producers in the system. I.e. use the old simple put_page() path when
there is no hmm or pmem.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mm/swap: Fix release_pages() when releasing devmap pages
2019-05-24 3:58 ` Dan Williams
2019-05-24 15:36 ` Ira Weiny
@ 2019-05-24 21:03 ` Dan Williams
1 sibling, 0 replies; 6+ messages in thread
From: Dan Williams @ 2019-05-24 21:03 UTC (permalink / raw)
To: Weiny, Ira
Cc: Andrew Morton, Michal Hocko, Linux MM, Linux Kernel Mailing List,
John Hubbard, Jérôme Glisse
On Thu, May 23, 2019 at 8:58 PM Dan Williams <dan.j.williams@intel.com> wrote:
>
> On Thu, May 23, 2019 at 3:37 PM <ira.weiny@intel.com> wrote:
> >
> > From: Ira Weiny <ira.weiny@intel.com>
> >
> > Device pages can be more than type MEMORY_DEVICE_PUBLIC.
> >
> > Handle all device pages within release_pages()
> >
> > This was found via code inspection while determining if release_pages()
> > and the new put_user_pages() could be interchangeable.
> >
> > Cc: Jérôme Glisse <jglisse@redhat.com>
> > Cc: Dan Williams <dan.j.williams@intel.com>
> > Cc: Michal Hocko <mhocko@suse.com>
> > Cc: John Hubbard <jhubbard@nvidia.com>
> > Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> > ---
> > mm/swap.c | 7 +++----
> > 1 file changed, 3 insertions(+), 4 deletions(-)
> >
> > diff --git a/mm/swap.c b/mm/swap.c
> > index 3a75722e68a9..d1e8122568d0 100644
> > --- a/mm/swap.c
> > +++ b/mm/swap.c
> > @@ -739,15 +739,14 @@ void release_pages(struct page **pages, int nr)
> > if (is_huge_zero_page(page))
> > continue;
> >
> > - /* Device public page can not be huge page */
> > - if (is_device_public_page(page)) {
> > + if (is_zone_device_page(page)) {
> > if (locked_pgdat) {
> > spin_unlock_irqrestore(&locked_pgdat->lru_lock,
> > flags);
> > locked_pgdat = NULL;
> > }
> > - put_devmap_managed_page(page);
> > - continue;
> > + if (put_devmap_managed_page(page))
>
> This "shouldn't" fail, and if it does the code that follows might get
> confused by a ZONE_DEVICE page. If anything I would make this a
> WARN_ON_ONCE(!put_devmap_managed_page(page)), but always continue
> unconditionally.
As discussed offline, I'm wrong here. It needs to fall through to
put_page_testzero() for the device-dax case, but perhaps a comment for
the next time I forget that subtlety.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2019-05-24 21:04 UTC | newest]
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2019-05-23 22:37 [PATCH] mm/swap: Fix release_pages() when releasing devmap pages ira.weiny
2019-05-24 1:05 ` John Hubbard
2019-05-24 3:58 ` Dan Williams
2019-05-24 15:36 ` Ira Weiny
2019-05-24 15:48 ` Dan Williams
2019-05-24 21:03 ` Dan Williams
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