Commit Graph

14 Commits

Author SHA1 Message Date
Christoph Hellwig e7d54ae83c fix asynchronous ioctls
posix_aio_read expect aio requests to return the number of bytes
requests to be successfull, so we need to fake this up for ioctls.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-05-08 15:51:19 -05:00
aliguori ceb42de899 native preadv/pwritev support (Christoph Hellwig)
This ties up the preadv/pwritev syscalls to qemu if they are declared in
unistd.h.  This is the case currently on at least NetBSD and OpenBSD and
will hopefully soon be the case on Linux.

Thanks to Blue Swirl and Gerd Hoffmann for the configure autodetection
of preadv/pwritev.


Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7021 c046a42c-6fe2-441c-8c8c-71466251a162
2009-04-07 18:43:28 +00:00
aliguori f141eafe28 push down vector linearization to posix-aio-compat.c (Christoph Hellwig)
Make all AIO requests vectored and defer linearization until the actual
I/O thread.  This prepares for using native preadv/pwritev.

Also enables asynchronous direct I/O by handling that case in the I/O thread.

Qcow and qcow2 propably want to be adopted to directly deal with multi-segment
requests, but that can be implemented later.


Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7020 c046a42c-6fe2-441c-8c8c-71466251a162
2009-04-07 18:43:24 +00:00
aliguori 221f715d90 new scsi-generic abstraction, use SG_IO (Christoph Hellwig)
Okay, I started looking into how to handle scsi-generic I/O in the
new world order.

I think the best is to use the SG_IO ioctl instead of the read/write
interface as that allows us to support scsi passthrough on disk/cdrom
devices, too.  See Hannes patch on the kvm list from August for an
example.

Now that we always do ioctls we don't need another abstraction than
bdrv_ioctl for the synchronous requests for now, and for asynchronous
requests I've added a aio_ioctl abstraction keeping it simple.

Long-term we might want to move the ops to a higher-level abstraction
and let the low-level code fill out the request header, but I'm lazy
enough to leave that to the people trying to support scsi-passthrough
on a non-Linux OS.

Tested lightly by issuing various sg_ commands from sg3-utils in a guest
to a host CDROM device.


Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6895 c046a42c-6fe2-441c-8c8c-71466251a162
2009-03-28 17:28:41 +00:00
malc 514f7a2774 Properly handle pthread_cond_timedwait timing out
pthread_cond_timedwait is allowed to both consume the signal and
return with the value indicating the timeout, hence predicate should
always be (re)checked before taking an action

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6634 c046a42c-6fe2-441c-8c8c-71466251a162
2009-02-21 05:48:19 +00:00
malc a8227a5a20 Cosmetics
Avoid repeated creation/initalization/destruction of attr and calls to
getpid

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6633 c046a42c-6fe2-441c-8c8c-71466251a162
2009-02-21 05:48:17 +00:00
malc 5d47e3728b Avoid thundering herd problem
Broadcast was used so that the I/O threads would wakeup, reset their
ts values and all but one go to sleep, in other words an optimization
to prevent threads from exiting in presence of continuing I/O
activity. Spurious wakeups make the looping around cond_timedwait with
ever reinitialized ts potentially unsafe and as such ts in no longer
reinitilized inside the loop, hence switch to signal is warranted and
this benefits of this particlaur optimization are lost.

(It's worth noting that timed variants of pthread calls use realtime
clock by default, and therefore can hang "forever" should the host
time be changed. Unfortunatelly not all host systems QEMU runs on
support CLOCK_MONOTONIC and/or pthread_condattr_setclock with this
value)

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6632 c046a42c-6fe2-441c-8c8c-71466251a162
2009-02-21 05:48:15 +00:00
malc 30525aff78 Avoid infinite loop around timed condition variable
This can happen due to spurious wakeups

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6631 c046a42c-6fe2-441c-8c8c-71466251a162
2009-02-21 05:48:13 +00:00
malc 8653c0158c Error checking
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6630 c046a42c-6fe2-441c-8c8c-71466251a162
2009-02-21 05:48:11 +00:00
blueswir1 55f11ca3c2 Rename sigev_signo to avoid FreeBSD problems (Juergen Lock)
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6414 c046a42c-6fe2-441c-8c8c-71466251a162
2009-01-24 11:54:21 +00:00
blueswir1 c9db92fcc1 Use kill instead of sigqueue: re-enables AIO on OpenBSD
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6360 c046a42c-6fe2-441c-8c8c-71466251a162
2009-01-17 06:49:15 +00:00
aliguori f094a78220 Fix race in POSIX AIO emulation (Jan Kiszka)
When we cancel an AIO request that is already being processed by
aio_thread, qemu_paio_cancel should return QEMU_PAIO_NOTCANCELED as long
as aio_thread isn't done with this request. But as the latter currently
updates aiocb->ret after every block of the request, we may report
QEMU_PAIO_ALLDONE too early.

Futhermore, in case some zero-length request should have been queued,
aiocb->ret is never set to != -EINPROGRESS and callers like
raw_aio_cancel could get stuck in an endless loop.

Fix those issues by updating aiocb->ret _after_ the request has been
fully processed. This also simplifies the locking.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6278 c046a42c-6fe2-441c-8c8c-71466251a162
2009-01-13 15:13:53 +00:00
blueswir1 1d6198c3b0 Remove unnecessary trailing newlines
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6000 c046a42c-6fe2-441c-8c8c-71466251a162
2008-12-13 09:32:43 +00:00
aliguori 3c529d9359 Replace posix-aio with custom thread pool
glibc implements posix-aio as a thread pool and imposes a number of limitations.

1) it limits one request per-file descriptor.  we hack around this by dup()'ing
file descriptors which is hideously ugly

2) it's impossible to add new interfaces and we need a vectored read/write
operation to properly support a zero-copy API.

What has been suggested to me by glibc folks, is to implement whatever new
interfaces we want and then it can eventually be proposed for standardization.
This requires that we implement our own posix-aio implementation though.

This patch implements posix-aio using pthreads.  It immediately eliminates the
need for fd pooling.

It performs at least as well as the current posix-aio code (in some
circumstances, even better).

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5996 c046a42c-6fe2-441c-8c8c-71466251a162
2008-12-12 16:41:40 +00:00