Deep rework of the xbdback(4) driver; it now uses a thread per instance

Browse Source

instead of continuations directly from shm callbacks or interrupt
handlers. The whole CPS design remains but is adapted to cope with
a thread model.

This patch allows scheduling away I/O requests of domains that behave
abnormally, or even destroy them if there is a need to (without thrashing
dom0 with lots of error messages at IPL_BIO).

I took this opportunity to make the driver MPSAFE, so multiple instances
can run concurrently. Moved from home-grown pool(9) queues to
pool_cache(9), and rework the callback mechanism so that it delegates
I/O processing to thread instead of handling it itself through the
continuation trampoline.

This one fixes the potential DoS many have seen in a dom0 when trying to
suspend a NetBSD domU with a corrupted I/O ring.

Benchmarks (build.sh release runs and bonnie++) do not show any
performance regression, the "new" driver is on-par with the "old" one.

ok bouyer@.

...

This commit is contained in:

jym 2011-11-24 01:47:18 +00:00

parent 408524dea5

commit 54f95b1441

1 changed files with 350 additions and 253 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Show Stats Download Patch File Download Diff File Expand all files Collapse all files

575

sys/arch/xen/xen/xbdback_xenbus.c

View File

File diff suppressed because it is too large Load Diff