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| author | David Rientjes <rientjes@google.com> | 2020-06-21 13:43:02 -0700 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2020-06-29 10:05:21 +0200 |
| commit | 71cdec4fab76667dabdbb2ca232b039004ebd40f (patch) | |
| tree | d02df4dce811a3f12c8e3ffe27e8e04acbb46f69 /kernel/dma | |
| parent | 9ebcfadb0610322ac537dd7aa5d9cbc2b2894c68 (diff) | |
| download | lwn-71cdec4fab76667dabdbb2ca232b039004ebd40f.tar.gz lwn-71cdec4fab76667dabdbb2ca232b039004ebd40f.zip | |
dma-mapping: warn when coherent pool is depleted
When a DMA coherent pool is depleted, allocation failures may or may not
get reported in the kernel log depending on the allocator.
The admin does have a workaround, however, by using coherent_pool= on the
kernel command line.
Provide some guidance on the failure and a recommended minimum size for
the pools (double the size).
Signed-off-by: David Rientjes <rientjes@google.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'kernel/dma')
| -rw-r--r-- | kernel/dma/pool.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c index 8cfa01243ed2..39ca26fa41b5 100644 --- a/kernel/dma/pool.c +++ b/kernel/dma/pool.c @@ -239,12 +239,16 @@ void *dma_alloc_from_pool(struct device *dev, size_t size, } val = gen_pool_alloc(pool, size); - if (val) { + if (likely(val)) { phys_addr_t phys = gen_pool_virt_to_phys(pool, val); *ret_page = pfn_to_page(__phys_to_pfn(phys)); ptr = (void *)val; memset(ptr, 0, size); + } else { + WARN_ONCE(1, "DMA coherent pool depleted, increase size " + "(recommended min coherent_pool=%zuK)\n", + gen_pool_size(pool) >> 9); } if (gen_pool_avail(pool) < atomic_pool_size) schedule_work(&atomic_pool_work); |