leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

mm/page_alloc: add __free_pages() documentation

Browse Source 
Provide some guidance towards when this might not be the right interface
to use.

Link: https://lkml.kernel.org/r/20201027025523.3235-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2020-12-14 19:11:09 -08:00 committed by Linus Torvalds
parent 3b12da6d1d
commit 7f194fbb2d
1 changed files with 20 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
mm/page_alloc.c
View File

@ -5043,6 +5043,26 @@ static inline void free_the_page(struct page *page, unsigned int order)
__free_pages_ok(page, order, FPI_NONE);
}
/**
* __free_pages - Free pages allocated with alloc_pages().
* @page: The page pointer returned from alloc_pages().
* @order: The order of the allocation.
*
* This function can free multi-page allocations that are not compound
* pages. It does not check that the @order passed in matches that of
* the allocation, so it is easy to leak memory. Freeing more memory
* than was allocated will probably emit a warning.
*
* If the last reference to this page is speculative, it will be released
* by put_page() which only frees the first page of a non-compound
* allocation. To prevent the remaining pages from being leaked, we free
* the subsequent pages here. If you want to use the page's reference
* count to decide when to free the allocation, you should allocate a
* compound page, and use put_page() instead of __free_pages().
*
* Context: May be called in interrupt context or while holding a normal
* spinlock, but not in NMI context or while holding a raw spinlock.
*/
void __free_pages(struct page *page, unsigned int order)
{
if (put_page_testzero(page))