2020-12-02 05:26:35

by Pasha Tatashin

[permalink] [raw]
Subject: [PATCH 1/6] mm/gup: perform check_dax_vmas only when FS_DAX is enabled

There is no need to check_dax_vmas() and run through the npage loop of
pinned pages if FS_DAX is not enabled.

Add a stub check_dax_vmas() function for no-FS_DAX case.

Signed-off-by: Pavel Tatashin <[email protected]>
---
mm/gup.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/mm/gup.c b/mm/gup.c
index 98eb8e6d2609..cdb8b9eeb016 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1568,6 +1568,7 @@ struct page *get_dump_page(unsigned long addr)
#endif /* CONFIG_ELF_CORE */

#if defined(CONFIG_FS_DAX) || defined (CONFIG_CMA)
+#ifdef CONFIG_FS_DAX
static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
{
long i;
@@ -1586,6 +1587,12 @@ static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
}
return false;
}
+#else
+static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
+{
+ return false;
+}
+#endif

#ifdef CONFIG_CMA
static long check_and_migrate_cma_pages(struct mm_struct *mm,
--
2.25.1


2020-12-02 16:24:41

by Ira Weiny

[permalink] [raw]
Subject: Re: [PATCH 1/6] mm/gup: perform check_dax_vmas only when FS_DAX is enabled

On Wed, Dec 02, 2020 at 12:23:25AM -0500, Pavel Tatashin wrote:
> There is no need to check_dax_vmas() and run through the npage loop of
> pinned pages if FS_DAX is not enabled.
>
> Add a stub check_dax_vmas() function for no-FS_DAX case.

This looks like a good idea.

>
> Signed-off-by: Pavel Tatashin <[email protected]>
> ---
> mm/gup.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/mm/gup.c b/mm/gup.c
> index 98eb8e6d2609..cdb8b9eeb016 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -1568,6 +1568,7 @@ struct page *get_dump_page(unsigned long addr)
> #endif /* CONFIG_ELF_CORE */
>
> #if defined(CONFIG_FS_DAX) || defined (CONFIG_CMA)

In addition, I think it would make a lot of sense to clean up this config as
well like this:

08:20:10 > git di
diff --git a/mm/gup.c b/mm/gup.c
index 102877ed77a4..92cfda220aeb 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1567,7 +1567,7 @@ struct page *get_dump_page(unsigned long addr)
}
#endif /* CONFIG_ELF_CORE */

-#if defined(CONFIG_FS_DAX) || defined (CONFIG_CMA)
+#ifdef CONFIG_FS_DAX
static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
{
long i;
@@ -1586,6 +1586,12 @@ static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
}
return false;
}
+#else
+static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
+{
+ return false;
+}
+#endif /* CONFIG_FS_DAX */

#ifdef CONFIG_CMA
static long check_and_migrate_cma_pages(struct mm_struct *mm,
@@ -1691,6 +1697,7 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm,
}
#endif /* CONFIG_CMA */

+#if defined(CONFIG_FS_DAX) || defined (CONFIG_CMA)
/*
* __gup_longterm_locked() is a wrapper for __get_user_pages_locked which
* allows us to process the FOLL_LONGTERM flag.


That makes it more clear what is going on with __gup_longterm_locked() and
places both CMA and FS_DAX code within their own blocks.

Ira

> +#ifdef CONFIG_FS_DAX
> static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
> {
> long i;
> @@ -1586,6 +1587,12 @@ static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
> }
> return false;
> }
> +#else
> +static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
> +{
> + return false;
> +}
> +#endif
>
> #ifdef CONFIG_CMA
> static long check_and_migrate_cma_pages(struct mm_struct *mm,
> --
> 2.25.1
>
>

2020-12-02 16:35:10

by Jason Gunthorpe

[permalink] [raw]
Subject: Re: [PATCH 1/6] mm/gup: perform check_dax_vmas only when FS_DAX is enabled

On Wed, Dec 02, 2020 at 12:23:25AM -0500, Pavel Tatashin wrote:
> There is no need to check_dax_vmas() and run through the npage loop of
> pinned pages if FS_DAX is not enabled.
>
> Add a stub check_dax_vmas() function for no-FS_DAX case.
>
> Signed-off-by: Pavel Tatashin <[email protected]>
> ---
> mm/gup.c | 7 +++++++
> 1 file changed, 7 insertions(+)

I have a patch to delete check_dax_vmas that is just waiting on me to
figure out how to test with dax. That makes all this ifdefery much
simpler

Jason

2020-12-02 18:18:22

by Pasha Tatashin

[permalink] [raw]
Subject: Re: [PATCH 1/6] mm/gup: perform check_dax_vmas only when FS_DAX is enabled

On Wed, Dec 2, 2020 at 11:22 AM Ira Weiny <[email protected]> wrote:
>
> On Wed, Dec 02, 2020 at 12:23:25AM -0500, Pavel Tatashin wrote:
> > There is no need to check_dax_vmas() and run through the npage loop of
> > pinned pages if FS_DAX is not enabled.
> >
> > Add a stub check_dax_vmas() function for no-FS_DAX case.
>
> This looks like a good idea.
>
> >
> > Signed-off-by: Pavel Tatashin <[email protected]>
> > ---
> > mm/gup.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/mm/gup.c b/mm/gup.c
> > index 98eb8e6d2609..cdb8b9eeb016 100644
> > --- a/mm/gup.c
> > +++ b/mm/gup.c
> > @@ -1568,6 +1568,7 @@ struct page *get_dump_page(unsigned long addr)
> > #endif /* CONFIG_ELF_CORE */
> >
> > #if defined(CONFIG_FS_DAX) || defined (CONFIG_CMA)
>
> In addition, I think it would make a lot of sense to clean up this config as
> well like this:
>
> 08:20:10 > git di
> diff --git a/mm/gup.c b/mm/gup.c
> index 102877ed77a4..92cfda220aeb 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -1567,7 +1567,7 @@ struct page *get_dump_page(unsigned long addr)
> }
> #endif /* CONFIG_ELF_CORE */
>
> -#if defined(CONFIG_FS_DAX) || defined (CONFIG_CMA)
> +#ifdef CONFIG_FS_DAX
> static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
> {
> long i;
> @@ -1586,6 +1586,12 @@ static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
> }
> return false;
> }
> +#else
> +static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
> +{
> + return false;
> +}
> +#endif /* CONFIG_FS_DAX */
>
> #ifdef CONFIG_CMA
> static long check_and_migrate_cma_pages(struct mm_struct *mm,
> @@ -1691,6 +1697,7 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm,
> }
> #endif /* CONFIG_CMA */
>
> +#if defined(CONFIG_FS_DAX) || defined (CONFIG_CMA)
> /*
> * __gup_longterm_locked() is a wrapper for __get_user_pages_locked which
> * allows us to process the FOLL_LONGTERM flag.
>
>
> That makes it more clear what is going on with __gup_longterm_locked() and
> places both CMA and FS_DAX code within their own blocks.

Hi Ira,

Thank you for your comments. I think the end result of what you are
suggesting is the same for this series when __gup_longterm_locked is
made common. " #if defined(CONFIG_FS_DAX) || defined (CONFIG_CMA)"
mess is removed in that patch.

Pasha

2020-12-02 18:20:15

by Pasha Tatashin

[permalink] [raw]
Subject: Re: [PATCH 1/6] mm/gup: perform check_dax_vmas only when FS_DAX is enabled

On Wed, Dec 2, 2020 at 11:30 AM Jason Gunthorpe <[email protected]> wrote:
>
> On Wed, Dec 02, 2020 at 12:23:25AM -0500, Pavel Tatashin wrote:
> > There is no need to check_dax_vmas() and run through the npage loop of
> > pinned pages if FS_DAX is not enabled.
> >
> > Add a stub check_dax_vmas() function for no-FS_DAX case.
> >
> > Signed-off-by: Pavel Tatashin <[email protected]>
> > ---
> > mm/gup.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
>
> I have a patch to delete check_dax_vmas that is just waiting on me to
> figure out how to test with dax. That makes all this ifdefery much
> simpler

Hi Jason,

Yeap, that would be nice. I made this change as a preparation for
moving __gup_longterm_locked into common code, so when you send your
patch it can remove both versions of check_dax_vmas.

Thank you,
Pasha

>
> Jason

2020-12-03 08:02:47

by John Hubbard

[permalink] [raw]
Subject: Re: [PATCH 1/6] mm/gup: perform check_dax_vmas only when FS_DAX is enabled

On 12/1/20 9:23 PM, Pavel Tatashin wrote:
> There is no need to check_dax_vmas() and run through the npage loop of
> pinned pages if FS_DAX is not enabled.
>
> Add a stub check_dax_vmas() function for no-FS_DAX case.
>
> Signed-off-by: Pavel Tatashin <[email protected]>
> ---
> mm/gup.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/mm/gup.c b/mm/gup.c
> index 98eb8e6d2609..cdb8b9eeb016 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -1568,6 +1568,7 @@ struct page *get_dump_page(unsigned long addr)
> #endif /* CONFIG_ELF_CORE */
>
> #if defined(CONFIG_FS_DAX) || defined (CONFIG_CMA)
> +#ifdef CONFIG_FS_DAX
> static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
> {
> long i;
> @@ -1586,6 +1587,12 @@ static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
> }
> return false;
> }
> +#else
> +static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
> +{
> + return false;
> +}
> +#endif
>
> #ifdef CONFIG_CMA
> static long check_and_migrate_cma_pages(struct mm_struct *mm,
>

Looks obviously correct, and the follow-up simplication is very nice.

Reviewed-by: John Hubbard <[email protected]>

thanks,
--
John Hubbard
NVIDIA

2020-12-03 14:57:27

by Pasha Tatashin

[permalink] [raw]
Subject: Re: [PATCH 1/6] mm/gup: perform check_dax_vmas only when FS_DAX is enabled

> Looks obviously correct, and the follow-up simplication is very nice.
>
> Reviewed-by: John Hubbard <[email protected]>

Thank you,
Pasha