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[Qemu-devel] [PATCH v2 0/9] main-loop: switch to g_poll(3) on POSIX host
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH v2 0/9] main-loop: switch to g_poll(3) on POSIX hosts |
Date: |
Fri, 1 Feb 2013 14:53:19 +0100 |
Amos Kong <address@hidden> reported that file descriptors numbered higher
than 1024 could crash QEMU. This is due to the fixed size of the fd_set type
used for select(2) event polling.
This series converts the main-loop.c and aio-posix.c select(2) calls to
g_poll(3). This eliminates the fd_set type and allows QEMU to scale to high
numbers of file descriptors.
The g_poll(3) interface is a portable version of the poll(2) system call. The
difference to select(2) is that fine-grained events (G_IO_IN, G_IO_OUT,
G_IO_HUP, G_IO_ERR, G_IO_PRI) can be monitored instead of just
read/write/exception. Also, there is no limit to the file descriptor numbers
that may be used, allowing applications to scale to many file descriptors. See
the documentation for details:
http://developer.gnome.org/glib/2.28/glib-The-Main-Event-Loop.html#g-poll
The QEMU main loop works as follows today:
1. Call out to slirp, iohandlers, and glib sources to fill rfds/wfds/xfds with
the file descriptors to select(2).
2. Perform the select(2) call.
3. Call out to slirp, iohandlers, and glib sources to handle events polled in
rfds/wfds/xfds.
The plan of attack is as follows:
1. Replace select(2) with g_poll(3). Use glue that converts between
rfds/wfds/xfds and GPollFD so that the unconverted QEMU components still
work.
2. Convert slirp, iohandlers, and glib source fill/poll functions to use
GPollFD directly instead of rfds/wfds/xfds.
3. Drop the glue since all components now natively use GPollFD.
4. Convert aio-posix.c to g_poll(3) by reusing GPollFD.
I have tested that the series builds and is bisectable on Linux and Windows
hosts. But I have not done extensive testing on other host platforms or with
long-term guests to check for performance regressions.
v2:
* Replace custom Poller type with GArray [aliguori]
Stefan Hajnoczi (9):
main-loop: fix select_ret uninitialized variable warning
main-loop: switch to g_poll() on POSIX hosts
main-loop: switch POSIX glib integration to GPollFD
slirp: switch to GPollFD
iohandler: switch to GPollFD
main-loop: drop rfds/wfds/xfds for good
aio: extract aio_dispatch() from aio_poll()
aio: convert aio_poll() to g_poll(3)
aio: support G_IO_HUP and G_IO_ERR
aio-posix.c | 130 ++++++++++++++++++---------------------
async.c | 2 +
include/block/aio.h | 3 +
include/qemu/main-loop.h | 4 +-
iohandler.c | 40 +++++++++---
main-loop.c | 156 ++++++++++++++++++++++++++---------------------
slirp/libslirp.h | 6 +-
slirp/main.h | 1 -
slirp/slirp.c | 136 ++++++++++++++++++++++++-----------------
slirp/socket.c | 9 ---
slirp/socket.h | 2 +
stubs/slirp.c | 6 +-
12 files changed, 270 insertions(+), 225 deletions(-)
--
1.8.1
- [Qemu-devel] [PATCH v2 0/9] main-loop: switch to g_poll(3) on POSIX hosts,
Stefan Hajnoczi <=
- [Qemu-devel] [PATCH v2 1/9] main-loop: fix select_ret uninitialized variable warning, Stefan Hajnoczi, 2013/02/01
- [Qemu-devel] [PATCH v2 2/9] main-loop: switch to g_poll() on POSIX hosts, Stefan Hajnoczi, 2013/02/01
- [Qemu-devel] [PATCH v2 3/9] main-loop: switch POSIX glib integration to GPollFD, Stefan Hajnoczi, 2013/02/01
- [Qemu-devel] [PATCH v2 4/9] slirp: switch to GPollFD, Stefan Hajnoczi, 2013/02/01
- [Qemu-devel] [PATCH v2 6/9] main-loop: drop rfds/wfds/xfds for good, Stefan Hajnoczi, 2013/02/01
- [Qemu-devel] [PATCH v2 5/9] iohandler: switch to GPollFD, Stefan Hajnoczi, 2013/02/01
- [Qemu-devel] [PATCH v2 7/9] aio: extract aio_dispatch() from aio_poll(), Stefan Hajnoczi, 2013/02/01
- [Qemu-devel] [PATCH v2 8/9] aio: convert aio_poll() to g_poll(3), Stefan Hajnoczi, 2013/02/01