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author | Robin Murphy <robin.murphy@arm.com> | 2018-12-10 17:00:30 +0300 |
---|---|---|
committer | Christoph Hellwig <hch@lst.de> | 2018-12-11 16:31:18 +0300 |
commit | ceb51173b2b5bd7af0d99079f6bbacdcfc58fe08 (patch) | |
tree | bc9245f7e98c8e07a1d203d143da808330c244fd /kernel/dma/debug.c | |
parent | 2b9d9ac02b9d8d32c515c82bb17401c429f160ab (diff) | |
download | linux-ceb51173b2b5bd7af0d99079f6bbacdcfc58fe08.tar.xz |
dma-debug: Make leak-like behaviour apparent
Now that we can dynamically allocate DMA debug entries to cope with
drivers maintaining excessively large numbers of live mappings, a driver
which *does* actually have a bug leaking mappings (and is not unloaded)
will no longer trigger the "DMA-API: debugging out of memory - disabling"
message until it gets to actual kernel OOM conditions, which means it
could go unnoticed for a while. To that end, let's inform the user each
time the pool has grown to a multiple of its initial size, which should
make it apparent that they either have a leak or might want to increase
the preallocation size.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Qian Cai <cai@lca.pw>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'kernel/dma/debug.c')
-rw-r--r-- | kernel/dma/debug.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c index ef7c90b7a346..912c23f4c177 100644 --- a/kernel/dma/debug.c +++ b/kernel/dma/debug.c @@ -691,6 +691,18 @@ static struct dma_debug_entry *__dma_entry_alloc(void) return entry; } +void __dma_entry_alloc_check_leak(void) +{ + u32 tmp = nr_total_entries % nr_prealloc_entries; + + /* Shout each time we tick over some multiple of the initial pool */ + if (tmp < DMA_DEBUG_DYNAMIC_ENTRIES) { + pr_info("dma_debug_entry pool grown to %u (%u00%%)\n", + nr_total_entries, + (nr_total_entries / nr_prealloc_entries)); + } +} + /* struct dma_entry allocator * * The next two functions implement the allocator for @@ -710,6 +722,7 @@ static struct dma_debug_entry *dma_entry_alloc(void) pr_err("debugging out of memory - disabling\n"); return NULL; } + __dma_entry_alloc_check_leak(); } entry = __dma_entry_alloc(); |