* Re: [PATCH V3 1/9] mm/gup: folio_add_pins [not found] ` <1728067700-32092-2-git-send-email-steven.sistare@oracle.com> @ 2024-10-04 18:52 ` Steven Sistare 2024-10-04 20:20 ` David Hildenbrand 0 siblings, 1 reply; 2+ messages in thread From: Steven Sistare @ 2024-10-04 18:52 UTC (permalink / raw) To: linux-mm Cc: Jason Gunthorpe, Kevin Tian, Nicolin Chen, iommu, Andrew Morton, David Hildenbrand, Matthew Wilcox cc mm folks. On 10/4/2024 2:48 PM, Steve Sistare wrote: > Export a function that adds pins to an already-pinned huge-page folio. > This allows any range of small pages within the folio to be unpinned later. > For example, pages pinned via memfd_pin_folios and modified by > folio_add_pins could be unpinned via unpin_user_page(s). > > Suggested-by: Jason Gunthorpe <jgg@nvidia.com> > Suggested-by: David Hildenbrand <david@redhat.com> > Signed-off-by: Steve Sistare <steven.sistare@oracle.com> > --- > include/linux/mm.h | 1 + > mm/gup.c | 24 ++++++++++++++++++++++++ > 2 files changed, 25 insertions(+) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 13bff7c..70d5293 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -2521,6 +2521,7 @@ long pin_user_pages_unlocked(unsigned long start, unsigned long nr_pages, > long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end, > struct folio **folios, unsigned int max_folios, > pgoff_t *offset); > +int folio_add_pins(struct folio *folio, unsigned int pins); > > int get_user_pages_fast(unsigned long start, int nr_pages, > unsigned int gup_flags, struct page **pages); > diff --git a/mm/gup.c b/mm/gup.c > index fcd602b..11c5f27 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -3733,3 +3733,27 @@ long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end, > return ret; > } > EXPORT_SYMBOL_GPL(memfd_pin_folios); > + > +/** > + * folio_add_pins() - add pins to an already-pinned folio > + * @folio: the folio to add more pins to > + * @pins: number of pins to add > + * > + * Try to add more pins to an already-pinned folio. The semantics > + * of the pin (e.g., FOLL_WRITE) follow any existing pin and cannot > + * be changed. > + * > + * This function is helpful when having obtained a pin on a large folio > + * using memfd_pin_folios(), but wanting to logically unpin parts > + * (e.g., individual pages) of the folio later, for example, using > + * unpin_user_page_range_dirty_lock(). > + * > + * This is not the right interface to initially pin a folio. > + */ > +int folio_add_pins(struct folio *folio, unsigned int pins) > +{ > + VM_WARN_ON_ONCE(!folio_maybe_dma_pinned(folio)); > + > + return try_grab_folio(folio, pins, FOLL_PIN); > +} > +EXPORT_SYMBOL_GPL(folio_add_pins); ^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH V3 1/9] mm/gup: folio_add_pins 2024-10-04 18:52 ` [PATCH V3 1/9] mm/gup: folio_add_pins Steven Sistare @ 2024-10-04 20:20 ` David Hildenbrand 0 siblings, 0 replies; 2+ messages in thread From: David Hildenbrand @ 2024-10-04 20:20 UTC (permalink / raw) To: Steven Sistare, linux-mm Cc: Jason Gunthorpe, Kevin Tian, Nicolin Chen, iommu, Andrew Morton, Matthew Wilcox, Nico Pache On 04.10.24 20:52, Steven Sistare wrote: > cc mm folks. > > On 10/4/2024 2:48 PM, Steve Sistare wrote: >> Export a function that adds pins to an already-pinned huge-page folio. >> This allows any range of small pages within the folio to be unpinned later. >> For example, pages pinned via memfd_pin_folios and modified by >> folio_add_pins could be unpinned via unpin_user_page(s). >> >> Suggested-by: Jason Gunthorpe <jgg@nvidia.com> >> Suggested-by: David Hildenbrand <david@redhat.com> >> Signed-off-by: Steve Sistare <steven.sistare@oracle.com> >> --- >> include/linux/mm.h | 1 + >> mm/gup.c | 24 ++++++++++++++++++++++++ >> 2 files changed, 25 insertions(+) >> >> diff --git a/include/linux/mm.h b/include/linux/mm.h >> index 13bff7c..70d5293 100644 >> --- a/include/linux/mm.h >> +++ b/include/linux/mm.h >> @@ -2521,6 +2521,7 @@ long pin_user_pages_unlocked(unsigned long start, unsigned long nr_pages, >> long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end, >> struct folio **folios, unsigned int max_folios, >> pgoff_t *offset); >> +int folio_add_pins(struct folio *folio, unsigned int pins); >> >> int get_user_pages_fast(unsigned long start, int nr_pages, >> unsigned int gup_flags, struct page **pages); >> diff --git a/mm/gup.c b/mm/gup.c >> index fcd602b..11c5f27 100644 >> --- a/mm/gup.c >> +++ b/mm/gup.c >> @@ -3733,3 +3733,27 @@ long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end, >> return ret; >> } >> EXPORT_SYMBOL_GPL(memfd_pin_folios); >> + >> +/** >> + * folio_add_pins() - add pins to an already-pinned folio >> + * @folio: the folio to add more pins to >> + * @pins: number of pins to add >> + * >> + * Try to add more pins to an already-pinned folio. The semantics >> + * of the pin (e.g., FOLL_WRITE) follow any existing pin and cannot >> + * be changed. >> + * >> + * This function is helpful when having obtained a pin on a large folio >> + * using memfd_pin_folios(), but wanting to logically unpin parts >> + * (e.g., individual pages) of the folio later, for example, using >> + * unpin_user_page_range_dirty_lock(). >> + * >> + * This is not the right interface to initially pin a folio. >> + */ >> +int folio_add_pins(struct folio *folio, unsigned int pins) >> +{ >> + VM_WARN_ON_ONCE(!folio_maybe_dma_pinned(folio)); >> + >> + return try_grab_folio(folio, pins, FOLL_PIN); >> +} >> +EXPORT_SYMBOL_GPL(folio_add_pins); > Acked-by: David Hildenbrand <david@redhat.com> -- Cheers, David / dhildenb ^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2024-10-04 20:20 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
[not found] <1728067700-32092-1-git-send-email-steven.sistare@oracle.com>
[not found] ` <1728067700-32092-2-git-send-email-steven.sistare@oracle.com>
2024-10-04 18:52 ` [PATCH V3 1/9] mm/gup: folio_add_pins Steven Sistare
2024-10-04 20:20 ` David Hildenbrand
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox