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| author | Kevin Hao <haokexin@gmail.com> | 2021-02-04 18:56:35 +0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-02-06 11:57:28 -0800 |
| commit | b358e2122b9d7aa99f681d4edfafd999845d16ff (patch) | |
| tree | 2bb2a9ee6ed3e4766ba90da3da0b8c521fbfe94d /mm | |
| parent | a455fcd7c77046d576dcfe41c1361928dd8b5eaf (diff) | |
| download | linux-b358e2122b9d7aa99f681d4edfafd999845d16ff.tar.bz2 | |
mm: page_frag: Introduce page_frag_alloc_align()
In the current implementation of page_frag_alloc(), it doesn't have
any align guarantee for the returned buffer address. But for some
hardwares they do require the DMA buffer to be aligned correctly,
so we would have to use some workarounds like below if the buffers
allocated by the page_frag_alloc() are used by these hardwares for
DMA.
buf = page_frag_alloc(really_needed_size + align);
buf = PTR_ALIGN(buf, align);
These codes seems ugly and would waste a lot of memories if the buffers
are used in a network driver for the TX/RX. So introduce
page_frag_alloc_align() to make sure that an aligned buffer address is
returned.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/page_alloc.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 519a60d5b6f7..ef5070fed76b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5137,8 +5137,9 @@ void __page_frag_cache_drain(struct page *page, unsigned int count) } EXPORT_SYMBOL(__page_frag_cache_drain); -void *page_frag_alloc(struct page_frag_cache *nc, - unsigned int fragsz, gfp_t gfp_mask) +void *page_frag_alloc_align(struct page_frag_cache *nc, + unsigned int fragsz, gfp_t gfp_mask, + unsigned int align_mask) { unsigned int size = PAGE_SIZE; struct page *page; @@ -5190,11 +5191,12 @@ refill: } nc->pagecnt_bias--; + offset &= align_mask; nc->offset = offset; return nc->va + offset; } -EXPORT_SYMBOL(page_frag_alloc); +EXPORT_SYMBOL(page_frag_alloc_align); /* * Frees a page fragment allocated out of either a compound or order 0 page. |