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authorDavid Rientjes <rientjes@google.com>2020-06-21 13:43:02 -0700
committerChristoph Hellwig <hch@lst.de>2020-06-29 10:05:21 +0200
commit71cdec4fab76667dabdbb2ca232b039004ebd40f (patch)
treed02df4dce811a3f12c8e3ffe27e8e04acbb46f69 /kernel/dma
parent9ebcfadb0610322ac537dd7aa5d9cbc2b2894c68 (diff)
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.c6
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);