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ARM: 8337/1: mm: Do not invoke OOM for higher order IOMMU DMA allocations 

IOMMU should be able to use single pages as well as bigger blocks, so if
higher order allocations fail, we should not affect state of the system,
with events such as OOM killer, but rather fall back to order 0
allocations.

This patch changes the behavior of ARM IOMMU DMA allocator to use
__GFP_NORETRY, which bypasses OOM invocation, for orders higher than
zero and, only if that fails, fall back to normal order 0 allocation
which might invoke OOM killer.

Signed-off-by: Tomasz Figa <tfiga@chromium.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Tomasz Figa 2015-04-01 07:26:33 +01:00 committed by Russell King
parent 8defb3367f
commit 49f28aa6b0
1 changed files with 21 additions and 6 deletions
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27
arch/arm/mm/dma-mapping.c
View File

@ -1135,13 +1135,28 @@ static struct page **__iommu_alloc_buffer(struct device *dev, size_t size,
gfp |= __GFP_NOWARN | __GFP_HIGHMEM;
while (count) {
int j, order = __fls(count);
int j, order;
pages[i] = alloc_pages(gfp, order);
while (!pages[i] && order)
pages[i] = alloc_pages(gfp, --order);
if (!pages[i])
goto error;
for (order = __fls(count); order > 0; --order) {
/*
* We do not want OOM killer to be invoked as long
* as we can fall back to single pages, so we force
* __GFP_NORETRY for orders higher than zero.
*/
pages[i] = alloc_pages(gfp | __GFP_NORETRY, order);
if (pages[i])
break;
}
if (!pages[i]) {
/*
* Fall back to single page allocation.
* Might invoke OOM killer as last resort.
*/
pages[i] = alloc_pages(gfp, 0);
if (!pages[i])
goto error;
}
if (order) {
split_page(pages[i], order);