On Thu, 3 Dec 2015 10:38:10 +0200 "Michael S. Tsirkin" <m...@redhat.com> wrote:
> The comment I put in mmap-alloc to document the ppc64 rules > refers to the previous revision of the patch: > we don't look at memory alignment anymore, we check > the fs from which the fd is mapped, instead. > > It's also not clear what does "in this case" refer > to, rearrange text to make it clearer. > > Signed-off-by: Michael S. Tsirkin <m...@redhat.com> > --- This is better indeed. Thanks ! Reviewed-by: Greg Kurz <gk...@linux.vnet.ibm.com> > util/mmap-alloc.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c > index 54793a5..5cd7f71 100644 > --- a/util/mmap-alloc.c > +++ b/util/mmap-alloc.c > @@ -50,10 +50,11 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, > bool shared) > #if defined(__powerpc64__) && defined(__linux__) > /* On ppc64 mappings in the same segment (aka slice) must share the same > * page size. Since we will be re-allocating part of this segment > - * from the supplied fd, we should make sure to use the same page size, > - * unless we are using the system page size, in which case anonymous > memory > - * is OK. Use align as a hint for the page size. > - * In this case, set MAP_NORESERVE to avoid allocating backing store > memory. > + * from the supplied fd, we should make sure to use the same page size, > to > + * this end we mmap the supplied fd. In this case, set MAP_NORESERVE to > + * avoid allocating backing store memory. > + * We do this unless we are using the system page size, in which case > + * anonymous memory is OK. > */ > int anonfd = fd == -1 || qemu_fd_getpagesize(fd) == getpagesize() ? -1 : > fd; > int flags = anonfd == -1 ? MAP_ANONYMOUS : MAP_NORESERVE;
