Ticket #1103 (new enhancement)

Opened 10 years ago

Last modified 10 years ago

Qemu gadgetfs needs to use asynchronous IO

Reported by: balrogg@… Owned by: balrogg@…
Priority: lowest Milestone:
Component: qemu-neo1973 Version: current svn head
Severity: minor Keywords:
Cc: buglog@… Blocked By:
Blocking: Estimated Completion (week):
HasPatchForReview: PatchReviewResult:
Reproducible:

Description

Qemu currently uses blocking calls to talk to gadgetfs. Gadgetfs under linux is
poorly written and perhaps unused by anyone for a at least a couple of years
before we started using it in qemu, so it doesn't support any kind of polling.
As a result qemu sometimes blocks waiting for usbnet to respond on the host.
Another side effect is qemu relies on the blocking calls getting interrupted by
signals, which is ok when using "unix" clocksource but rules out "dynticks", so
currently I'm disabling dynticks every time usbgadget is used, it's a hack.
Before upstreaming gadgetfs needs to be rewritten to use AIO. Otherwise low
priority.

Change History

comment:1 Changed 10 years ago by balrogg@…

  • blocked set to 1102
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