Commit Graph

40 Commits

Author SHA1 Message Date
Michael Tokarev 520b6dd4d0 main-loop: do not include slirp/slirp.h, use libslirp.h instead
The header slirp/slirp.h is an internal header for slirp, and
main-loop.c does not use internals from there.  Instead, it uses
public functions (slirp_update_timeout(), slirp_pollfds_fill()
etc) which are declared in slirp/libslirp.h.

Including slirp/slirp.h is somewhat dangerous since it redefines
errno on WIN32, so any file including it may misbehave wrt errno.

Unfortunately libslirp isn't self-contained, it needs declaration
of struct in_addr, which is provided by qemu/sockets.h.  Maybe
instead of #including qemu/sockets.h before libslirp.h, it is
better to make the latter self-contained.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
2013-06-12 18:43:08 +04:00
Stefan Hajnoczi 3cb8c205e3 main-loop: partial revert of 5e3bc73
This patch reverts part of 5e3bc735d9.

Paolo Bonzini wrote this patch and commented:

"WSAEventSelect is edge-triggered and the event will not be signaled if
the socket handler does not consume all the data in the socket buffer."

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1368718561-7816-3-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-05-16 14:18:47 -05:00
Stefan Hajnoczi 8db165b36e main-loop: narrow win32 pollfds_fill() event bitmasks
pollfds_fill() and pollfds_poll() translate GPollFD to rfds/wfds/xfds
for sockets on win32.  select(2) is the underlying system call which is
used to monitor sockets for activity.

Currently file descriptors that monitor G_IO_ERR will be included in
both rfds and wfds.  As a result, select(2) will report writability on
file descriptors where we only really wanted to monitor readability
(with errors).

slirp_pollfds_poll() hit this issue: UDP sockets are blocking sockets so
we hang in sorecvfrom() when G_IO_ERR is set due to the socket being
writable (we only wanted to check for readability).

This patch fixes the slirp_pollfds_poll() hang.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1368718561-7816-2-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-05-16 14:18:47 -05:00
Anthony Liguori 893986fe94 main-loop: drop the BQL if the I/O appears to be spinning
The char-flow refactoring introduced a busy-wait that depended on
an action from the VCPU thread.  However, the VCPU thread could
never take that action because the busy-wait starved the VCPU thread
of the BQL because it never dropped the mutex while running select.

Paolo doesn't want to drop this optimization for fear that we will
stop detecting these busy waits.  I'm afraid to keep this optimization
even with the busy-wait fixed because I think a similar problem can
occur just with heavy I/O thread load manifesting itself as VCPU pauses.

As a compromise, introduce an artificial timeout after a thousand
iterations but print a rate limited warning when this happens.  This
let's us still detect when this condition occurs without it being
a fatal error.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Message-id: 1365169560-11012-1-git-send-email-aliguori@us.ibm.com
2013-04-05 12:53:33 -05:00
Stefan Hajnoczi 5f3aa1ff47 main-loop: add qemu_get_aio_context()
It is very useful to get the main loop AioContext, which is a static
variable in main-loop.c.

I'm not sure whether qemu_get_aio_context() will be necessary in the
future once devices focus on using their own AioContext instead of the
main loop AioContext, but for now it allows us to refactor code to
support multiple AioContext while actually passing the main loop
AioContext.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
2013-03-15 16:07:50 +01:00
Stefan Hajnoczi 9cbaacf999 main-loop: drop rfds/wfds/xfds for good
Now that all *_fill() and *_poll() functions use GPollFD we no longer
need rfds/wfds/xfds or pollfds_from_select()/pollfds_to_select().

>From now on everything uses GPollFD.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 1361356113-11049-8-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-02-21 16:17:31 -06:00
Stefan Hajnoczi a3e4b4a809 iohandler: switch to GPollFD
Convert iohandler_select_fill() and iohandler_select_poll() to use
GPollFD instead of rfds/wfds/xfds.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 1361356113-11049-7-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-02-21 16:17:31 -06:00
Stefan Hajnoczi 8917c3bdba slirp: switch to GPollFD
Slirp uses rfds/wfds/xfds more extensively than other QEMU components.

The rarely-used out-of-band TCP data feature is used.  That means we
need the full table of select(2) to g_poll(3) events:

  rfds -> G_IO_IN | G_IO_HUP | G_IO_ERR
  wfds -> G_IO_OUT | G_IO_ERR
  xfds -> G_IO_PRI

I came up with this table by looking at Linux fs/select.c which maps
select(2) to poll(2) internally.

Another detail to watch out for are the global variables that reference
rfds/wfds/xfds during slirp_select_poll().  sofcantrcvmore() and
sofcantsendmore() use these globals to clear fd_set bits.  When
sofcantrcvmore() is called, the wfds bit is cleared so that the write
handler will no longer be run for this iteration of the event loop.

This actually seems buggy to me since TCP connections can be half-closed
and we'd still want to handle data in half-duplex fashion.  I think the
real intention is to avoid running the read/write handler when the
socket has been fully closed.  This is indicated with the SS_NOFDREF
state bit so we now check for it before invoking the TCP write handler.
Note that UDP/ICMP code paths don't care because they are
connectionless.

Note that slirp/ has a lot of tabs and sometimes mixed tabs with spaces.
I followed the style of the surrounding code.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 1361356113-11049-6-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-02-21 16:17:31 -06:00
Stefan Hajnoczi 48ce11ff97 main-loop: switch POSIX glib integration to GPollFD
Convert glib file descriptor polling from rfds/wfds/xfds to GPollFD.

The Windows code still needs poll_fds[] and n_poll_fds but they can now
become local variables.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 1361356113-11049-4-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-02-21 16:17:30 -06:00
Stefan Hajnoczi cbff4b342b main-loop: switch to g_poll() on POSIX hosts
Use g_poll(3) instead of select(2).  Well, this is kind of a cheat.
It's true that we're now using g_poll(3) on POSIX hosts but the *_fill()
and *_poll() functions are still using rfds/wfds/xfds.

We've set the scene to start converting *_fill() and *_poll() functions
step-by-step until no more rfds/wfds/xfds users remain.  Then we'll drop
the temporary gpollfds_from_select() and gpollfds_to_select() functions
and be left with native g_poll(2).

On Windows things are a little crazy: convert from rfds/wfds/xfds to
GPollFDs, back to rfds/wfds/xfds, call select(2), rfds/wfds/xfds back to
GPollFDs, and finally back to rfds/wfds/xfds again.  This is only
temporary and keeps the Windows build working through the following
patches.  We'll drop this excessive conversion later and be left with a
single GPollFDs -> select(2) -> GPollFDs sequence that allows Windows to
use select(2) while the rest of QEMU only knows about GPollFD.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 1361356113-11049-3-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-02-21 16:17:30 -06:00
Stefan Hajnoczi 134a03e0b3 main-loop: fix select_ret uninitialized variable warning
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 1361356113-11049-2-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-02-21 16:17:30 -06:00
Fabien Chouteau 5e3bc735d9 Check return values from g_poll and select
The current implementation of os_host_main_loop_wait() on Windows,
returns 1 only when a g_poll() event occurs because the return value of
select() is overridden. This is wrong as we may skip a socket event, as
shown in this example:

1. select() returns 0
2. g_poll() returns 1  (socket event occurs)
3. os_host_main_loop_wait() returns 1
4. qemu_iohandler_poll() sees no socket event because select() has
   return before the event occurs
5. select() returns 1
6. g_poll() returns 0 (g_poll overrides select's return value)
7. os_host_main_loop_wait() returns 0
8. qemu_iohandler_poll() doesn't check for socket events because the
   return value of os_host_main_loop_wait() is zero.
9. goto 5

This patch use one variable for each of these return values, so we don't
miss a select() event anymore.

Also move the call to select() after g_poll(), this will improve latency
as we don't have to go through two os_host_main_loop_wait() calls to
detect a socket event.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Fabien Chouteau <chouteau@adacore.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-01-09 11:03:05 -06:00
Paolo Bonzini 1de7afc984 misc: move include files to include/qemu/
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19 08:32:39 +01:00
Paolo Bonzini 737e150e89 block: move include files to include/block/
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19 08:31:31 +01:00
Kevin Wolf c57b6656c3 aio: Get rid of qemu_aio_flush()
There are no remaining users, and new users should probably be
using bdrv_drain_all() in the first place.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-12-11 11:04:25 +01:00
Paolo Bonzini 49cf57281b vl: delay thread initialization after daemonization
Commit ac4119c (chardev: Use timer instead of bottom-half to postpone
open event, 2012-10-12) moved the alarm timer initialization to an earlier
point but failed to consider that it depends on qemu_init_main_loop.

Later, commit 1c53786 (vl: init main loop earlier, 2012-10-30) fixed
this, but left -daemonize in two different ways.  First, timers need to
be reinitialized after forking.  Second, the global mutex was being held
by the parent, and thus dropped after forking.

The first is now fixed using pthread_atfork.  For the second part,
make sure that the global mutex is not taken before daemonization,
and similarly delay qemu_thread_self.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-11-02 13:07:55 -05:00
Paolo Bonzini f9ab4654e3 vl: unify calls to init_timer_alarm
init_timer_alarm was being called twice.  This is not needed.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-11-02 13:07:54 -05:00
Paolo Bonzini 4c8d0d2767 main-loop: use aio_notify for qemu_notify_event
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-10-30 09:30:54 +01:00
Paolo Bonzini 82cbbdc6a0 main-loop: use GSource to poll AIO file descriptors
This lets us remove the hooks for the main loop in async.c.

Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-10-30 09:30:53 +01:00
Paolo Bonzini f42b22077b aio: add Win32 implementation
The Win32 implementation will only accept EventNotifiers, thus a few
drivers are disabled under Windows.  EventNotifiers are a good match
for the GSource implementation, too, because the Win32 port of glib
allows to place their HANDLEs in a GPollFD.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-10-30 09:30:53 +01:00
Paolo Bonzini 7c0628b20e aio: add non-blocking variant of aio_wait
This will be used when polling the GSource attached to an AioContext.

Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-10-30 09:30:53 +01:00
Paolo Bonzini a915f4bc97 aio: add I/O handlers to the AioContext interface
With this patch, I/O handlers (including event notifier handlers) can be
attached to a single AioContext.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-10-30 09:30:53 +01:00
Paolo Bonzini f627aab1cc aio: introduce AioContext, move bottom halves there
Start introducing AioContext, which will let us remove globals from
aio.c/async.c, and introduce multiple I/O threads.

The bottom half functions now take an additional AioContext argument.
A bottom half is created with a specific AioContext that remains the
same throughout the lifetime.  qemu_bh_new is just a wrapper that
uses a global context.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-10-30 09:30:53 +01:00
Paolo Bonzini 172061a0a0 main-loop: unify qemu_init_main_loop between QEMU and tools
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-10-30 09:18:44 +01:00
Stefan Weil 3239ad0469 main-loop: Calculate poll timeout using timeout argument
The timeout argument was unused up to now,
but it can be used to reduce the poll_timeout when it is infinite
(negative value) or larger than timeout.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-05-01 10:46:25 +00:00
Stefan Weil 42fe1c245f main-loop: Fix build for w32 and w64
This patch fixes a build regression with MinGW which was introduced by
commit 7c7db75576.

The 3rd argument of g_main_context_query must point to a gint value.
Using a pointer to an uint32_t value is wrong.

The timeout argument of function os_host_main_loop_wait was never
used for w32 / w64.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-04-28 09:25:54 +00:00
Stefano Stabellini 7c7db75576 main_loop_wait: block indefinitely
- remove qemu_calculate_timeout;

- explicitly size timeout to uint32_t;

- introduce slirp_update_timeout;

- pass NULL as timeout argument to select in case timeout is the maximum
value;

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Paul Brook <paul@codesourcery.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-04-26 13:14:58 -05:00
Stefan Weil 58b9630d7e w64: Fix type cast in os_host_main_loop_wait
Casting a pointer to an integer must use (DWORD_PTR) instead of (DWORD).
This also matches the definition of 'fd' (gint for w32, gint64 for w64).

Signed-off-by: Stefan Weil <sw@weilnetz.de>
2012-04-15 21:25:17 +02:00
Anthony Liguori 72fe3aaed9 Merge remote-tracking branch 'stefanha/trivial-patches' into staging
* stefanha/trivial-patches:
  make: fix clean rule by removing build file in qom/
  configure: Link qga against UST tracing related libraries
  configure: Link QEMU against 'liburcu-bp'
  main-loop: make qemu_event_handle static
  block/curl: Replace usleep by g_usleep
  qtest: Add missing GCC_FMT_ATTR
  w32: Undefine error constants before their redefinition
  configure: fix mingw32 libs_qga typo
2012-04-10 08:10:41 -05:00
Paolo Bonzini ea26ce765c main-loop: integrate glib sources for w32
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-04-07 08:34:18 +00:00
Paolo Bonzini 06ac7d4979 main-loop: replace WaitForMultipleObjects with g_poll
On w32, glib implements g_poll using WaitForMultipleObjects
or MsgWaitForMultipleObjects.  This means that we can simplify
our code by switching to g_poll, and at the same time prepare for
adding back glib sources.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-04-07 08:34:17 +00:00
Paolo Bonzini d3385eb448 main-loop: interrupt wait when data arrives on a socket
Right now, the main loop is not interrupted when data arrives on a
socket.  To fix this, register each socket to interrupt the main loop
with WSAEventSelect.  This does not replace select, it only communicates
a change in socket state that requires a select call.

Since the interrupt fires only once per recv call, or only once
after a send call returns EWOULDBLOCK we can activate it on all events
unconditionally.  If QEMU is momentarily uninterested on some condition,
the main loop will not busy wait.  Instead, it may get one extra wakeup,
but then it will ignore the condition until progress occurs and/or
qemu_set_fd_handler is called to set a callback.  At this point the
condition will be tested via select and the callback will be invoked
even if it is still disabled on the event.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-04-07 08:34:16 +00:00
Paolo Bonzini 15455536df main-loop: disable fd_set-based glib integration under w32
Using select with glib pollfds is wrong under w32.  Restrict
the code to the POSIX case.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-04-07 08:34:15 +00:00
Paolo Bonzini 4dae83aeac main loop: use msec-based timeout in glib_select_fill
The timeval-based timeout is not needed until we actually invoke select,
so compute it only then.  Also group the two calls that modify the
timeout, glib_select_fill and os_host_main_loop_wait.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-04-07 08:34:15 +00:00
Frediano Ziglio a92433afcc main-loop: make qemu_event_handle static
Signed-off-by: Frediano Ziglio <freddy77@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2012-04-03 09:34:34 +01:00
Michael Roth d34e8f6e9d main-loop: For tools, initialize timers as part of qemu_init_main_loop()
In some cases initializing the alarm timers can lead to non-negligable
overhead from programs that link against qemu-tool.o. At least,
setting a max-resolution WinMM alarm timer via mm_start_timer() (the
current default for Windows) can increase the "tick rate" on Windows
OSs and affect frequency scaling, and in the case of tools that run
in guest OSs such has qemu-ga, the impact can be fairly dramatic
(+20%/20% user/sys time on a core 2 processor was observed from an idle
Windows XP guest).

This patch doesn't address the issue directly (not sure what a good
solution would be for Windows, or what other situations it might be
noticeable), but it at least limits the scope of the issue to programs
that "opt-in" to using the main-loop.c functions by only enabling alarm
timers when qemu_init_main_loop() is called, which is already required
to make use of those facilities, so existing users shouldn't be
affected.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-02-01 14:45:02 -06:00
Michael Roth ee77dfb26a main-loop: Fix SetEvent() on uninitialized handle on win32
The __attribute__((constructor)) init_main_loop() automatically get
called if qemu-tool.o is linked in. On win32, this leads to
a qemu_notify_event() call which attempts to SetEvent() on a HANDLE that
won't be initialized until qemu_init_main_loop() is manually called,
breaking qemu-tools.o programs on Windows at runtime.

This patch checks for an initialized event handle before attempting to
set it, which is analoguous to how we deal with an unitialized
io_thread_fd in the posix implementation.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-02-01 14:45:02 -06:00
Lai Jiangshan 4aa7534d22 cleanup, save a syscall
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-12 10:34:20 -06:00
Stefan Weil 0ec024f636 main-loop: Add missing include file
stdint.h defines the POSIX data types and is needed
for MinGW-w64 (and maybe other hosts).

v2: Instead of adding stdint.h directly, qemu-common.h is now
included and duplicate include statements were removed.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-10-25 15:38:08 -05:00
Paolo Bonzini d3b12f5dec main-loop: create main-loop.c
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2011-10-21 18:14:30 +02:00