On 2011-01-25 01:02, Anthony Liguori wrote: > On 01/24/2011 04:24 PM, Jan Kiszka wrote: >> On 2011-01-24 22:00, Anthony Liguori wrote: >> >>> Signed-off-by: Anthony Liguori<aligu...@us.ibm.com> >>> >>> diff --git a/cpus.c b/cpus.c >>> index 9cf7e6e..0f8e33b 100644 >>> --- a/cpus.c >>> +++ b/cpus.c >>> @@ -321,8 +321,8 @@ void vm_stop(int reason) >>> >>> #include "qemu-thread.h" >>> >>> -QemuMutex qemu_global_mutex; >>> -static QemuMutex qemu_fair_mutex; >>> +GStaticMutex qemu_global_mutex; >>> +static GStaticMutex qemu_fair_mutex; >>> >>> static QemuThread io_thread; >>> >>> @@ -416,9 +416,9 @@ int qemu_init_main_loop(void) >>> qemu_cond_init(&qemu_system_cond); >>> qemu_cond_init(&qemu_pause_cond); >>> qemu_cond_init(&qemu_work_cond); >>> - qemu_mutex_init(&qemu_fair_mutex); >>> - qemu_mutex_init(&qemu_global_mutex); >>> - qemu_mutex_lock(&qemu_global_mutex); >>> + g_static_mutex_init(&qemu_fair_mutex); >>> + g_static_mutex_init(&qemu_global_mutex); >>> + g_static_mutex_lock(&qemu_global_mutex); >>> >>> >> Just replacing our own abstraction with glib's looks like a step in the >> wrong direction. From a first glance at that library and its semantics >> it has at least two major drawbacks: >> >> - Error handling of things like g_mutex_lock or g_cond_wait is, well, >> very "simplistic". Once we start to use more sophisticated locking, >> more bugs will occur here, and we will need more support than glib is >> able to provide (or can you control error handling elsewhere?). >> >> - GMutex is not powerful enough for optional things like PI mutexes - >> which is required once we want to schedule parts of qemu with RT >> priorities (I did it, it works surprisingly well). >> > > One of the nice design characteristics of glib/gobject/gtk is that it > cohabitates well with other APIs. > > Nothing stops you from using pthread mutex directly if you really need > to. It makes you less portable, but sometimes it's a price that has to > be paid for functionality.
I'm not talking about adding new PI mutexes, I'm talking about effectively reverting this patch as I need to initializes the existing ones with PI enabled in the attributes. Or replacing g_mutex_* with wrappers again to add real error handling. Really, glib is too primitive here. Jan
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