Hi Linus, On Friday, November 10, 2017 11:01:31 AM Linus Walleij wrote: > This is the fifth iteration of this patch set. > > I *HOPE* that we can scrap this patch set and merge Adrian's > patches instead, because they also bring CQE support which is > nice. I had some review comments on his series, mainly that > it needs to kill off the legacy block layer code path that > noone likes anyway. > > So this is mainly an academic and inspirational exercise. > Whatever remains of this refactoring, if anything, I can > certainly do on top of Adrian's patches as well. > > What changed since v4 is the error path, since Adrian pointed > out that the error handling seems to be fragile. It was indeed > fragile... To make sure things work properly I have run long > test rounds with fault injection, essentially: > > Enable FAULT_INJECTION, FAULT_INJECTION_DEBUG_FS, > FAIL_MMC_REQUEST > cd /debug/mmc3/fail_mmc_request/ > echo 1 > probability > echo -1 > times > > Then running a dd to the card, also increased the error rate > to 10% and completed tests successfully, but at this error > rate the MMC stack sometimes exceeds the retry limit and the > dd command fails (as is appropriate). > > Removing a card during I/O does not work well however :/ > So I guess I would need to work on that if this series should > continue. (Hopefully unlikely.) > > > Linus Walleij (12): > mmc: core: move the asynchronous post-processing > mmc: core: add a workqueue for completing requests > mmc: core: replace waitqueue with worker > mmc: core: do away with is_done_rcv > mmc: core: do away with is_new_req > mmc: core: kill off the context info > mmc: queue: simplify queue logic > mmc: block: shuffle retry and error handling > mmc: queue: stop flushing the pipeline with NULL > mmc: queue/block: pass around struct mmc_queue_req*s > mmc: block: issue requests in massive parallel > mmc: switch MMC/SD to use blk-mq multiqueueing v5 > > drivers/mmc/core/block.c | 557 +++++++++++++++++++++++--------------------- > drivers/mmc/core/block.h | 5 +- > drivers/mmc/core/bus.c | 1 - > drivers/mmc/core/core.c | 217 ++++++++++------- > drivers/mmc/core/core.h | 11 +- > drivers/mmc/core/host.c | 1 - > drivers/mmc/core/mmc_test.c | 31 +-- > drivers/mmc/core/queue.c | 252 ++++++++------------ > drivers/mmc/core/queue.h | 16 +- > include/linux/mmc/core.h | 3 +- > include/linux/mmc/host.h | 31 +-- > 11 files changed, 557 insertions(+), 568 deletions(-) This works much better than initial version and a simple dd read test shows more consistent results than with vanilla kernel. However there are still some issues: 1. 30 seconds delay on "Waiting for /dev to be fully populated..." during boot 2. reboot command no longer works (there is a livelock after "The system is going down for reboot NOW!" message) Full log (together with SysRq-l & SysRq-t outputs) attached. Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics
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