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mm/gup: add a range variant of unpin_user_pages_dirty_lock() 

Add an unpin_user_page_range_dirty_lock() API which takes a starting page
and how many consecutive pages we want to unpin and optionally dirty.

To that end, define another iterator for_each_compound_range() that
operates in page ranges as opposed to page array.

For users (like RDMA mr_dereg) where each sg represents a contiguous set
of pages, we're able to more efficiently unpin pages without having to
supply an array of pages much of what happens today with
unpin_user_pages().

Link: https://lkml.kernel.org/r/20210212130843.13865-4-joao.m.martins@oracle.com
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joao Martins 2021-04-29 22:55:50 -07:00 committed by Linus Torvalds
parent 31b912de13
commit 458a4f788f
2 changed files with 64 additions and 0 deletions
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2
include/linux/mm.h
View File

@ -1265,6 +1265,8 @@ static inline void put_page(struct page *page)
void unpin_user_page(struct page *page);
void unpin_user_pages_dirty_lock(struct page **pages, unsigned long npages,
bool make_dirty);
void unpin_user_page_range_dirty_lock(struct page *page, unsigned long npages,
bool make_dirty);
void unpin_user_pages(struct page **pages, unsigned long npages);
/**

62
mm/gup.c
View File

@ -213,6 +213,32 @@ void unpin_user_page(struct page *page)
}
EXPORT_SYMBOL(unpin_user_page);
static inline void compound_range_next(unsigned long i, unsigned long npages,
struct page **list, struct page **head,
unsigned int *ntails)
{
struct page *next, *page;
unsigned int nr = 1;
if (i >= npages)
return;
next = *list + i;
page = compound_head(next);
if (PageCompound(page) && compound_order(page) >= 1)
nr = min_t(unsigned int,
page + compound_nr(page) - next, npages - i);
*head = page;
*ntails = nr;
}
#define for_each_compound_range(__i, __list, __npages, __head, __ntails) \
for (__i = 0, \
compound_range_next(__i, __npages, __list, &(__head), &(__ntails)); \
__i < __npages; __i += __ntails, \
compound_range_next(__i, __npages, __list, &(__head), &(__ntails)))
static inline void compound_next(unsigned long i, unsigned long npages,
struct page **list, struct page **head,
unsigned int *ntails)
@ -301,6 +327,42 @@ void unpin_user_pages_dirty_lock(struct page **pages, unsigned long npages,
}
EXPORT_SYMBOL(unpin_user_pages_dirty_lock);
/**
* unpin_user_page_range_dirty_lock() - release and optionally dirty
* gup-pinned page range
*
* @page: the starting page of a range maybe marked dirty, and definitely released.
* @npages: number of consecutive pages to release.
* @make_dirty: whether to mark the pages dirty
*
* "gup-pinned page range" refers to a range of pages that has had one of the
* pin_user_pages() variants called on that page.
*
* For the page ranges defined by [page .. page+npages], make that range (or
* its head pages, if a compound page) dirty, if @make_dirty is true, and if the
* page range was previously listed as clean.
*
* set_page_dirty_lock() is used internally. If instead, set_page_dirty() is
* required, then the caller should a) verify that this is really correct,
* because _lock() is usually required, and b) hand code it:
* set_page_dirty_lock(), unpin_user_page().
*
*/
void unpin_user_page_range_dirty_lock(struct page *page, unsigned long npages,
bool make_dirty)
{
unsigned long index;
struct page *head;
unsigned int ntails;
for_each_compound_range(index, &page, npages, head, ntails) {
if (make_dirty && !PageDirty(head))
set_page_dirty_lock(head);
put_compound_head(head, ntails, FOLL_PIN);
}
}
EXPORT_SYMBOL(unpin_user_page_range_dirty_lock);
/**
* unpin_user_pages() - release an array of gup-pinned pages.
* @pages: array of pages to be marked dirty and released.