path: root/coroutine-ucontext.c
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2013-04-17Fix warnings suppressors to honor --disable-werrorMarkus Armbruster
Replace #pragma GCC diagnostic ignored FOO [Troublesome code...] #pragma GCC diagnostic error FOO by #pragma GCC diagnostic push #pragma GCC diagnostic ignored FOO [Troublesome code...] #pragma GCC diagnostic pop Broken in commit 3f4349d, commit 092bb30, and commit c95e308. Signed-off-by: Markus Armbruster <armbru@redhat.com> Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1366113066-1340-1-git-send-email-armbru@redhat.com Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-02-26Merge remote-tracking branch 'kwolf/for-anthony' into stagingAnthony Liguori
# By Paolo Bonzini (7) and others # Via Kevin Wolf * kwolf/for-anthony: (22 commits) pc: add compatibility machine types for 1.4 blockdev: enable discard by default qemu-nbd: add --discard option blockdev: add discard suboption to -drive block: implement BDRV_O_UNMAP block: complete all IOs before .bdrv_truncate coroutine: trim down nesting level in perf_nesting test coroutine: move pooling to common code qemu-iotests: Test qcow2 image creation options qemu-iotests: Add qemu-img compare test qemu-img: Add compare subcommand qemu-img: Add "Quiet mode" option block: Add synchronous wrapper for bdrv_co_is_allocated_above block: refuse negative iops and bps values block: use Error in do_check_io_limits() qcow2: support compressed clusters in BlockFragInfo qemu-img: add compressed clusters to BlockFragInfo qemu-img: fix missing space in qemu-img check output qcow2: record fragmentation statistics during check qcow2: introduce check_refcounts_l1/l2() flags ...
2013-02-23Replace all setjmp()/longjmp() with sigsetjmp()/siglongjmp()Peter Maydell
The setjmp() function doesn't specify whether signal masks are saved and restored; on Linux they are not, but on BSD (including MacOSX) they are. We want to have consistent behaviour across platforms, so we should always use "don't save/restore signal mask" (this is also generally going to be faster). This also works around a bug in MacOSX where the signal-restoration on longjmp() affects the signal mask for a completely different thread, not just the mask for the thread which did the longjmp. The most visible effect of this was that ctrl-C was ignored on MacOSX because the CPU thread did a longjmp which resulted in its signal mask being applied to every thread, so that all threads had SIGINT and SIGTERM blocked. The POSIX-sanctioned portable way to do a jump without affecting signal masks is to siglongjmp() to a sigjmp_buf which was created by calling sigsetjmp() with a zero savemask parameter, so change all uses of setjmp()/longjmp() accordingly. [Technically POSIX allows sigsetjmp(buf, 0) to save the signal mask; however the following siglongjmp() must not restore the signal mask, so the pair can be effectively considered as "sigjmp/longjmp which don't touch the mask".] For Windows we provide a trivial sigsetjmp/siglongjmp in terms of setjmp/longjmp -- this is OK because no user will ever pass a non-zero savemask. The setjmp() uses in tests/tcg/test-i386.c and tests/tcg/linux-test.c are left untouched because these are self-contained singlethreaded test programs intended to be run under QEMU's Linux emulation, so they have neither the portability nor the multithreading issues to deal with. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <rth@twiddle.net> Tested-by: Stefan Weil <sw@weilnetz.de> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2013-02-22coroutine: move pooling to common codePaolo Bonzini
The coroutine pool code is duplicated between the ucontext and sigaltstack backends, and absent from the win32 backend. But the code can be shared easily by moving it to qemu-coroutine.c. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-01-12gcc: rename CONFIG_PRAGMA_DISABLE_UNUSED_BUT_SET to ↵Gerd Hoffmann
CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-12-19block: move include files to include/block/Paolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-07-31configure: Split valgrind test into pragma test and valgrind.h testPeter Maydell
Split the configure test that checks for valgrind into two, one part checking whether we have the gcc pragma to disable unused-but-set variables, and the other part checking for the existence of valgrind.h. The first of these has to be compiled with -Werror and the second does not and shouldn't generate any warnings. This (a) allows us to enable "make errors in configure tests be build failures" and (b) enables use of valgrind on systems with a gcc which doesn't know about -Wunused-but-set-varibale, like Debian squeeze. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-07-17coroutine-ucontext: Help valgrind understand coroutinesKevin Wolf
valgrind tends to get confused and report false positives when you switch stacks and don't tell it about it. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
2012-02-17coroutine: switch to QSLISTPaolo Bonzini
QSLIST can be used for a free list, do it. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-12-15coroutine: switch per-thread free pool to a global poolAvi Kivity
ucontext-based coroutines use a free pool to reduce allocations and deallocations of coroutine objects. The pool is per-thread, presumably to improve locality. However, as coroutines are usually allocated in a vcpu thread and freed in the I/O thread, the pool accounting gets screwed up and we end allocating and freeing a coroutine for every I/O request. This is expensive since large objects are allocated via the kernel, and are not cached by the C runtime. Fix by switching to a global pool. This is safe since we're protected by the global mutex. Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-08-20Use glib memory allocation and free functionsAnthony Liguori
qemu_malloc/qemu_free no longer exist after this commit. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-08-08Unbreak the build on ppc32malc
Signed-off-by: malc <av1474@comtv.ru>
2011-08-01coroutine: introduce coroutinesKevin Wolf
Asynchronous code is becoming very complex. At the same time synchronous code is growing because it is convenient to write. Sometimes duplicate code paths are even added, one synchronous and the other asynchronous. This patch introduces coroutines which allow code that looks synchronous but is asynchronous under the covers. A coroutine has its own stack and is therefore able to preserve state across blocking operations, which traditionally require callback functions and manual marshalling of parameters. Creating and starting a coroutine is easy: coroutine = qemu_coroutine_create(my_coroutine); qemu_coroutine_enter(coroutine, my_data); The coroutine then executes until it returns or yields: void coroutine_fn my_coroutine(void *opaque) { MyData *my_data = opaque; /* do some work */ qemu_coroutine_yield(); /* do some more work */ } Yielding switches control back to the caller of qemu_coroutine_enter(). This is typically used to switch back to the main thread's event loop after issuing an asynchronous I/O request. The request callback will then invoke qemu_coroutine_enter() once more to switch back to the coroutine. Note that if coroutines are used only from threads which hold the global mutex they will never execute concurrently. This makes programming with coroutines easier than with threads. Race conditions cannot occur since only one coroutine may be active at any time. Other coroutines can only run across yield. This coroutines implementation is based on the gtk-vnc implementation written by Anthony Liguori <anthony@codemonkey.ws> but it has been significantly rewritten by Kevin Wolf <kwolf@redhat.com> to use setjmp()/longjmp() instead of the more expensive swapcontext() and by Paolo Bonzini <pbonzini@redhat.com> for Windows Fibers support. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>