[KVM PATCH v7 0/5] irqfd fixes and enhancements

From: Gregory Haskins
Date: Mon Jun 29 2009 - 14:29:30 EST


(Applies to kvm.git/master:4631e094)

The following is the latest attempt to fix the races in irqfd/eventfd, as
well as restore DEASSIGN support. For more details, please read the patch
headers. I've restored the slow-work variant of the logic as a separate
patch (5/5) so we can get a better idea of the true difference between
the workqueue approach and the slow-work style. I am personally in favor
of the slow-work approach since it doesnt require a mostly-idle+dedicated
thread to hang around. But that is just me. 5/5 can be ignored, folded
in to 3/5+4/5 as appropriate, or merged as is per the whim of Avi et. al.

As always, this series has been tested against the kvm-eventfd unit test
with both 5/5 applied and unapplied, and everything appears to be
functioning properly. You can download this test here:

ftp://ftp.novell.com/dev/ghaskins/kvm-eventfd.tar.bz2

I've included version 4 of Davide's eventfd patch (ported to kvm.git) so
that its a complete reviewable series. Note, however, that there may be
later versions of his patch to consider for merging, so we should
coordinate with him.

-Greg


[Changelog:

v7:
*) Addressed minor-nit feedback from Michael
*) Cleaned up patch headers
*) Re-added separate slow-work feature patch to end for comparison

v6:
*) Removed slow-work in favor of using a dedicated single-thread
workqueue.
*) Condensed cleanup path to always use deferred shutdown
*) Saved about 56 lines over v5, with the following diffstat:

include/linux/kvm_host.h | 2
virt/kvm/eventfd.c | 248 ++++++++++++++++++-----------------------------
2 files changed, 97 insertions(+), 153 deletions(-)
v5:
Untracked..
]

---

Davide Libenzi (1):
eventfd - revised interface and cleanups (4th rev)

Gregory Haskins (4):
KVM: Make irqfd use slow-work for shutdown
KVM: add irqfd DEASSIGN feature
KVM: Fix races in irqfd using new eventfd_kref_get interface
kvm: prepare irqfd for having interrupts disabled during eventfd->release


drivers/lguest/lg.h | 2
drivers/lguest/lguest_user.c | 4 -
fs/aio.c | 24 +---
fs/eventfd.c | 126 ++++++++++++++++++----
include/linux/aio.h | 4 -
include/linux/eventfd.h | 35 +++++-
include/linux/kvm.h | 2
include/linux/kvm_host.h | 7 +
virt/kvm/Kconfig | 1
virt/kvm/eventfd.c | 246 ++++++++++++++++++++++++++++++++----------
10 files changed, 343 insertions(+), 108 deletions(-)

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