| Message ID | 78b49fc7e0302be282b4fcbd3f71fa4ae38e2d5f.1725941415.git-series.apopple@nvidia.com |
|---|---|
| State | New |
| Headers | show |
| Series | fs/dax: Fix FS DAX page reference counts | expand |
Alistair Popple wrote: > Longterm pinning of FS DAX pages should already be disallowed by > various pXX_devmap checks. However a future change will cause these > checks to be invalid for FS DAX pages so make > folio_is_longterm_pinnable() return false for FS DAX pages. > > Signed-off-by: Alistair Popple <apopple@nvidia.com> > --- > include/linux/memremap.h | 11 +++++++++++ > include/linux/mm.h | 4 ++++ > 2 files changed, 15 insertions(+) > > diff --git a/include/linux/memremap.h b/include/linux/memremap.h > index 14273e6..6a1406a 100644 > --- a/include/linux/memremap.h > +++ b/include/linux/memremap.h > @@ -187,6 +187,17 @@ static inline bool folio_is_device_coherent(const struct folio *folio) > return is_device_coherent_page(&folio->page); > } > > +static inline bool is_device_dax_page(const struct page *page) > +{ > + return is_zone_device_page(page) && > + page_dev_pagemap(page)->type == MEMORY_DEVICE_FS_DAX; > +} > + > +static inline bool folio_is_device_dax(const struct folio *folio) > +{ > + return is_device_dax_page(&folio->page); > +} > + > #ifdef CONFIG_ZONE_DEVICE > void zone_device_page_init(struct page *page); > void *memremap_pages(struct dev_pagemap *pgmap, int nid); > diff --git a/include/linux/mm.h b/include/linux/mm.h > index ae6d713..935e493 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1989,6 +1989,10 @@ static inline bool folio_is_longterm_pinnable(struct folio *folio) > if (folio_is_device_coherent(folio)) > return false; > > + /* DAX must also always allow eviction. */ > + if (folio_is_device_dax(folio)) Why is this called "folio_is_device_dax()" when the check is for fsdax? I would expect: if (folio_is_fsdax(folio)) return false; ...and s/device_dax/fsdax/ for the rest of the helpers.
Dan Williams wrote: > Alistair Popple wrote: > > Longterm pinning of FS DAX pages should already be disallowed by > > various pXX_devmap checks. However a future change will cause these > > checks to be invalid for FS DAX pages so make > > folio_is_longterm_pinnable() return false for FS DAX pages. > > > > Signed-off-by: Alistair Popple <apopple@nvidia.com> > > --- > > include/linux/memremap.h | 11 +++++++++++ > > include/linux/mm.h | 4 ++++ > > 2 files changed, 15 insertions(+) > > > > diff --git a/include/linux/memremap.h b/include/linux/memremap.h > > index 14273e6..6a1406a 100644 > > --- a/include/linux/memremap.h > > +++ b/include/linux/memremap.h > > @@ -187,6 +187,17 @@ static inline bool folio_is_device_coherent(const struct folio *folio) > > return is_device_coherent_page(&folio->page); > > } > > > > +static inline bool is_device_dax_page(const struct page *page) > > +{ > > + return is_zone_device_page(page) && > > + page_dev_pagemap(page)->type == MEMORY_DEVICE_FS_DAX; > > +} > > + > > +static inline bool folio_is_device_dax(const struct folio *folio) > > +{ > > + return is_device_dax_page(&folio->page); > > +} > > + > > #ifdef CONFIG_ZONE_DEVICE > > void zone_device_page_init(struct page *page); > > void *memremap_pages(struct dev_pagemap *pgmap, int nid); > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > index ae6d713..935e493 100644 > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -1989,6 +1989,10 @@ static inline bool folio_is_longterm_pinnable(struct folio *folio) > > if (folio_is_device_coherent(folio)) > > return false; > > > > + /* DAX must also always allow eviction. */ > > + if (folio_is_device_dax(folio)) > > Why is this called "folio_is_device_dax()" when the check is for fsdax? > > I would expect: > > if (folio_is_fsdax(folio)) > return false; > > ...and s/device_dax/fsdax/ for the rest of the helpers. Specifically devdax is ok to allow longterm pinning since it is statically allocated. fsdax is the only ZONE_DEVICE mode where there is a higher-level allocator that does not support a 3rd party the block its operations indefinitely with a pin. So this needs to be explicit for that case.
Dan Williams <dan.j.williams@intel.com> writes: > Dan Williams wrote: >> Alistair Popple wrote: >> > Longterm pinning of FS DAX pages should already be disallowed by >> > various pXX_devmap checks. However a future change will cause these >> > checks to be invalid for FS DAX pages so make >> > folio_is_longterm_pinnable() return false for FS DAX pages. >> > >> > Signed-off-by: Alistair Popple <apopple@nvidia.com> >> > --- >> > include/linux/memremap.h | 11 +++++++++++ >> > include/linux/mm.h | 4 ++++ >> > 2 files changed, 15 insertions(+) >> > >> > diff --git a/include/linux/memremap.h b/include/linux/memremap.h >> > index 14273e6..6a1406a 100644 >> > --- a/include/linux/memremap.h >> > +++ b/include/linux/memremap.h >> > @@ -187,6 +187,17 @@ static inline bool folio_is_device_coherent(const struct folio *folio) >> > return is_device_coherent_page(&folio->page); >> > } >> > >> > +static inline bool is_device_dax_page(const struct page *page) >> > +{ >> > + return is_zone_device_page(page) && >> > + page_dev_pagemap(page)->type == MEMORY_DEVICE_FS_DAX; >> > +} >> > + >> > +static inline bool folio_is_device_dax(const struct folio *folio) >> > +{ >> > + return is_device_dax_page(&folio->page); >> > +} >> > + >> > #ifdef CONFIG_ZONE_DEVICE >> > void zone_device_page_init(struct page *page); >> > void *memremap_pages(struct dev_pagemap *pgmap, int nid); >> > diff --git a/include/linux/mm.h b/include/linux/mm.h >> > index ae6d713..935e493 100644 >> > --- a/include/linux/mm.h >> > +++ b/include/linux/mm.h >> > @@ -1989,6 +1989,10 @@ static inline bool folio_is_longterm_pinnable(struct folio *folio) >> > if (folio_is_device_coherent(folio)) >> > return false; >> > >> > + /* DAX must also always allow eviction. */ >> > + if (folio_is_device_dax(folio)) >> >> Why is this called "folio_is_device_dax()" when the check is for fsdax? >> >> I would expect: >> >> if (folio_is_fsdax(folio)) >> return false; >> >> ...and s/device_dax/fsdax/ for the rest of the helpers. > > Specifically devdax is ok to allow longterm pinning since it is > statically allocated. fsdax is the only ZONE_DEVICE mode where there is > a higher-level allocator that does not support a 3rd party the block its > operations indefinitely with a pin. So this needs to be explicit for > that case. Yeah, that all makes sense. I see what I did - was thinking in terms of is this a zone device page - is_device - and if so what type _(fs)dax. folio_is_fsdax() is much clearer though, thanks!
diff --git a/include/linux/memremap.h b/include/linux/memremap.h index 14273e6..6a1406a 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -187,6 +187,17 @@ static inline bool folio_is_device_coherent(const struct folio *folio) return is_device_coherent_page(&folio->page); } +static inline bool is_device_dax_page(const struct page *page) +{ + return is_zone_device_page(page) && + page_dev_pagemap(page)->type == MEMORY_DEVICE_FS_DAX; +} + +static inline bool folio_is_device_dax(const struct folio *folio) +{ + return is_device_dax_page(&folio->page); +} + #ifdef CONFIG_ZONE_DEVICE void zone_device_page_init(struct page *page); void *memremap_pages(struct dev_pagemap *pgmap, int nid); diff --git a/include/linux/mm.h b/include/linux/mm.h index ae6d713..935e493 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1989,6 +1989,10 @@ static inline bool folio_is_longterm_pinnable(struct folio *folio) if (folio_is_device_coherent(folio)) return false; + /* DAX must also always allow eviction. */ + if (folio_is_device_dax(folio)) + return false; + /* Otherwise, non-movable zone folios can be pinned. */ return !folio_is_zone_movable(folio);
Longterm pinning of FS DAX pages should already be disallowed by various pXX_devmap checks. However a future change will cause these checks to be invalid for FS DAX pages so make folio_is_longterm_pinnable() return false for FS DAX pages. Signed-off-by: Alistair Popple <apopple@nvidia.com> --- include/linux/memremap.h | 11 +++++++++++ include/linux/mm.h | 4 ++++ 2 files changed, 15 insertions(+)