hi, I cannot possible give any consideration to this caching layer until I'm happy with the code I got from you for stripe batching, and I'm not. I asked: Subject: Re: [PATCH 7/7] md/raid5: fix handling of degraded stripes in batches. Date: Wed, 13 May 2015 10:56:04 +1000 > What exactly do you expect to happen after the stripes in a batch after they > have been split up? and haven't received a reply yet. Did you not get that email? Thanks, NeilBrown On Mon, 18 May 2015 19:57:28 -0700 Shaohua Li <shli@xxxxxx> wrote: > Hi, > > This is the second version of the raid5/6 caching layer patches. The patches add a > caching layer for raid5/6. The caching layer uses a SSD as a cache for a raid > 5/6. It works like the similar way of a hardware raid controller. The purpose > is to improve raid performance (reduce read-modify-write) and fix write hole > issue. The main patch is patch 3 and the description has all details about the > implementation. > > Main changes of V2 are to improve performance. Meta data write doesn't use FUA > any more. Discard request is only dispatched when discard range is big enough. > Also have some bug fixing and code cleanup. Please review! > > Thanks, > Shaohua > > > Shaohua Li (5): > raid5: directly use mddev->queue > raid5: A caching layer for RAID5/6 > raid5: add some sysfs entries > md: don't allow resize/reshape with cache support > raid5: skip resync if caching is enabled > > Song Liu (1): > MD: add a new disk role to present cache device > > drivers/md/Makefile | 2 +- > drivers/md/md.c | 14 +- > drivers/md/md.h | 4 + > drivers/md/raid5-cache.c | 3519 ++++++++++++++++++++++++++++++++++++++++ > drivers/md/raid5.c | 97 +- > drivers/md/raid5.h | 16 +- > include/uapi/linux/raid/md_p.h | 73 + > 7 files changed, 3705 insertions(+), 20 deletions(-) > create mode 100644 drivers/md/raid5-cache.c >
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