p71924506
/
linux_old1
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

mm: Add folio_get() 

If we know we have a folio, we can call folio_get() instead
of get_page() and save the overhead of calling compound_head().
No change to generated code.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jeff Layton <jlayton@kernel.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
This commit is contained in:
Matthew Wilcox (Oracle) 2020-12-06 23:04:57 -05:00
parent b620f63358
commit 86d234cb04
1 changed files with 17 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
include/linux/mm.h
View File

@ -1224,18 +1224,26 @@ static inline bool is_pci_p2pdma_page(const struct page *page)
}
/* 127: arbitrary random number, small enough to assemble well */
#define page_ref_zero_or_close_to_overflow(page) \
((unsigned int) page_ref_count(page) + 127u <= 127u)
#define folio_ref_zero_or_close_to_overflow(folio) \
((unsigned int) folio_ref_count(folio) + 127u <= 127u)
/**
* folio_get - Increment the reference count on a folio.
* @folio: The folio.
*
* Context: May be called in any context, as long as you know that
* you have a refcount on the folio. If you do not already have one,
* folio_try_get() may be the right interface for you to use.
*/
static inline void folio_get(struct folio *folio)
{
VM_BUG_ON_FOLIO(folio_ref_zero_or_close_to_overflow(folio), folio);
folio_ref_inc(folio);
}
static inline void get_page(struct page *page)
{
page = compound_head(page);
/*
* Getting a normal page or the head of a compound page
* requires to already have an elevated page->_refcount.
*/
VM_BUG_ON_PAGE(page_ref_zero_or_close_to_overflow(page), page);
page_ref_inc(page);
folio_get(page_folio(page));
}
bool __must_check try_grab_page(struct page *page, unsigned int flags);