Commit 5157b4aa5b7de8787b6318e61bcc285031bb9088
Committed by
Linus Torvalds
Linus Torvalds
1 parent
7ebd467551
raid6: fix recovery performance regression
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. Cc: <stable@kernel.org> 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>
Showing 1 changed file with 13 additions and 8 deletions Side-by-side Diff
crypto/async_tx/async_raid6_recov.c
| ... | ... | @@ -324,6 +324,7 @@ |
| 324 | 324 | async_raid6_2data_recov(int disks, size_t bytes, int faila, int failb, |
| 325 | 325 | struct page **blocks, struct async_submit_ctl *submit) |
| 326 | 326 | { |
| 327 | + void *scribble = submit->scribble; | |
| 327 | 328 | int non_zero_srcs, i; |
| 328 | 329 | |
| 329 | 330 | BUG_ON(faila == failb); |
| 330 | 331 | |
| ... | ... | @@ -332,11 +333,13 @@ |
| 332 | 333 | |
| 333 | 334 | pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes); |
| 334 | 335 | |
| 335 | - /* we need to preserve the contents of 'blocks' for the async | |
| 336 | - * case, so punt to synchronous if a scribble buffer is not available | |
| 336 | + /* if a dma resource is not available or a scribble buffer is not | |
| 337 | + * available punt to the synchronous path. In the 'dma not | |
| 338 | + * available' case be sure to use the scribble buffer to | |
| 339 | + * preserve the content of 'blocks' as the caller intended. | |
| 337 | 340 | */ |
| 338 | - if (!submit->scribble) { | |
| 339 | - void **ptrs = (void **) blocks; | |
| 341 | + if (!async_dma_find_channel(DMA_PQ) || !scribble) { | |
| 342 | + void **ptrs = scribble ? scribble : (void **) blocks; | |
| 340 | 343 | |
| 341 | 344 | async_tx_quiesce(&submit->depend_tx); |
| 342 | 345 | for (i = 0; i < disks; i++) |
| 343 | 346 | |
| ... | ... | @@ -406,11 +409,13 @@ |
| 406 | 409 | |
| 407 | 410 | pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes); |
| 408 | 411 | |
| 409 | - /* we need to preserve the contents of 'blocks' for the async | |
| 410 | - * case, so punt to synchronous if a scribble buffer is not available | |
| 412 | + /* if a dma resource is not available or a scribble buffer is not | |
| 413 | + * available punt to the synchronous path. In the 'dma not | |
| 414 | + * available' case be sure to use the scribble buffer to | |
| 415 | + * preserve the content of 'blocks' as the caller intended. | |
| 411 | 416 | */ |
| 412 | - if (!scribble) { | |
| 413 | - void **ptrs = (void **) blocks; | |
| 417 | + if (!async_dma_find_channel(DMA_PQ) || !scribble) { | |
| 418 | + void **ptrs = scribble ? scribble : (void **) blocks; | |
| 414 | 419 | |
| 415 | 420 | async_tx_quiesce(&submit->depend_tx); |
| 416 | 421 | for (i = 0; i < disks; i++) |