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| author | Dan Williams <dan.j.williams@intel.com> | 2010-05-04 20:41:56 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-05-12 14:57:05 -0700 |
| commit | b228f7fdef669dbcefbf0414b89583c8422f0e19 (patch) | |
| tree | da84c762a72f8b9ae917d1a5bdb8b3898d0482d4 | |
| parent | ef0c64308b5dfa779b0c22508ad755abe49938ac (diff) | |
| download | lwn-b228f7fdef669dbcefbf0414b89583c8422f0e19.tar.gz lwn-b228f7fdef669dbcefbf0414b89583c8422f0e19.zip | |
raid6: fix recovery performance regression
commit 5157b4aa5b7de8787b6318e61bcc285031bb9088 upstream.
The raid6 recovery code should immediately drop back to the optimized
synchronous path when a p+q dma resource is not available. Otherwise we
run the non-optimized/multi-pass async code in sync mode.
Verified with raid6test (NDISKS=255)
Applies to kernels >= 2.6.32.
Acked-by: NeilBrown <neilb@suse.de>
Reported-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | crypto/async_tx/async_raid6_recov.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/crypto/async_tx/async_raid6_recov.c b/crypto/async_tx/async_raid6_recov.c index 943f2abac9b4..ce038d861eb9 100644 --- a/crypto/async_tx/async_raid6_recov.c +++ b/crypto/async_tx/async_raid6_recov.c @@ -324,6 +324,7 @@ struct dma_async_tx_descriptor * async_raid6_2data_recov(int disks, size_t bytes, int faila, int failb, struct page **blocks, struct async_submit_ctl *submit) { + void *scribble = submit->scribble; int non_zero_srcs, i; BUG_ON(faila == failb); @@ -332,11 +333,13 @@ async_raid6_2data_recov(int disks, size_t bytes, int faila, int failb, pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes); - /* we need to preserve the contents of 'blocks' for the async - * case, so punt to synchronous if a scribble buffer is not available + /* if a dma resource is not available or a scribble buffer is not + * available punt to the synchronous path. In the 'dma not + * available' case be sure to use the scribble buffer to + * preserve the content of 'blocks' as the caller intended. */ - if (!submit->scribble) { - void **ptrs = (void **) blocks; + if (!async_dma_find_channel(DMA_PQ) || !scribble) { + void **ptrs = scribble ? scribble : (void **) blocks; async_tx_quiesce(&submit->depend_tx); for (i = 0; i < disks; i++) @@ -406,11 +409,13 @@ async_raid6_datap_recov(int disks, size_t bytes, int faila, pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes); - /* we need to preserve the contents of 'blocks' for the async - * case, so punt to synchronous if a scribble buffer is not available + /* if a dma resource is not available or a scribble buffer is not + * available punt to the synchronous path. In the 'dma not + * available' case be sure to use the scribble buffer to + * preserve the content of 'blocks' as the caller intended. */ - if (!scribble) { - void **ptrs = (void **) blocks; + if (!async_dma_find_channel(DMA_PQ) || !scribble) { + void **ptrs = scribble ? scribble : (void **) blocks; async_tx_quiesce(&submit->depend_tx); for (i = 0; i < disks; i++) |