Re: [Qemu-devel] [PATCH v3 1/3] util/mmap-alloc: support MAP_SYNC in qemu_ram_mmap()

[Haozhong Zhang]

On 01/24/18 22:20 +0200, Michael S. Tsirkin wrote:
> > index 50385e3f81..dd5876471f 100644
> > --- a/include/qemu/mmap-alloc.h
> > +++ b/include/qemu/mmap-alloc.h
> > @@ -7,7 +7,8 @@ size_t qemu_fd_getpagesize(int fd);
> >  
> >  size_t qemu_mempath_getpagesize(const char *mem_path);
> >  
> > -void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared);
> > +void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared,
> > +                    OnOffAuto sync);
> >  
> >  void qemu_ram_munmap(void *ptr, size_t size);
> >  
> 
> And Marcel plans to add a remappable flag ...  Is it time we
> switched to a flags field?

Yes. Some patches on my hands are going to add another field to this
function, so let's switch to flags.

> 
> > diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> > index adb3758275..0ff10cb529 100644
> > --- a/include/qemu/osdep.h
> > +++ b/include/qemu/osdep.h
> > @@ -372,6 +372,24 @@ void qemu_anon_ram_free(void *ptr, size_t size);
> >  #  define QEMU_VMALLOC_ALIGN getpagesize()
> >  #endif
> >  
> > +/*
> > + * MAP_SHARED_VALIDATE and MAP_SYNC were introduced in Linux kernel
> > + * 4.15, so they may not be defined when compiling on older kernels.
> > + */
> > +#ifdef CONFIG_LINUX
> > +#ifndef MAP_SHARED_VALIDATE
> > +#define MAP_SHARED_VALIDATE   0x3
> > +#endif
> > +#ifndef MAP_SYNC
> > +#define MAP_SYNC              0x80000
> > +#endif
> > +#define QEMU_HAS_MAP_SYNC     true
> > +#else  /* !CONFIG_LINUX */
> > +#define MAP_SHARED_VALIDATE   0x0
> > +#define MAP_SYNC              0x0
> > +#define QEMU_HAS_MAP_SYNC     false
> > +#endif /* CONFIG_LINUX */
> > +
> >  #ifdef CONFIG_POSIX
> >  struct qemu_signalfd_siginfo {
> >      uint32_t ssi_signo;   /* Signal number */
> 
> Please just import this into standard-headers from Linux.
>

Sure, I'll move it to a new file include/standard-headers/linux/mman.h.

Thanks,
Haozhong