On Wed, 19 Feb 2014 10:03:13 +0100
Paolo Bonzini <pbonz...@redhat.com> wrote:
> 19/02/2014 08:54, Hu Tao ha scritto:
> > Thus makes user control how to allocate memory for ram backend.
> >
> > Signed-off-by: Hu Tao <hu...@cn.fujitsu.com>
> > ---
> > backends/hostmem-ram.c | 158
> > ++++++++++++++++++++++++++++++++++++++++++++++++
> > include/sysemu/sysemu.h | 2 +
> > 2 files changed, 160 insertions(+)
> >
> > diff --git a/backends/hostmem-ram.c b/backends/hostmem-ram.c
[...]
> > static int
> > ram_backend_memory_init(HostMemoryBackend *backend, Error **errp)
> > {
> > + HostMemoryBackendRam *ram_backend = MEMORY_BACKEND_RAM(backend);
> > + int mode = ram_backend->policy;
> > + void *p;
> > + unsigned long maxnode;
> > +
> > if (!memory_region_size(&backend->mr)) {
> > memory_region_init_ram(&backend->mr, OBJECT(backend),
> > object_get_canonical_path(OBJECT(backend)),
> > backend->size);
> > +
> > + p = memory_region_get_ram_ptr(&backend->mr);
> > + maxnode = find_last_bit(ram_backend->host_nodes, MAX_NODES);
> > +
> > + mode |= ram_backend->relative ? MPOL_F_RELATIVE_NODES :
> > + MPOL_F_STATIC_NODES;
> > + /* This is a workaround for a long standing bug in Linux'
> > + * mbind implementation, which cuts off the last specified
> > + * node. To stay compatible should this bug be fixed, we
> > + * specify one more node and zero this one out.
> > + */
> > + if (syscall(SYS_mbind, p, backend->size, mode,
> > + ram_backend->host_nodes, maxnode + 2, 0)) {
>
> This does not compile on non-Linux; also, does libnuma include the
> workaround? If so, this is a hint that we should be using libnuma
> instead...
>
> Finally, all this code should be in hostmem.c, not hostmem-ram.c,
> because the same policies can be applied to hugepage-backed memory.
>
> Currently host_memory_backend_get_memory is calling bc->memory_init.
> Probably the call should be replaced by something like
I've pushed to github updated version of memdev, where
host_memory_backend_get_memory() is just convenience wrapper to get
access to memdev's internal MemoryRegion.
All initialization now is done in user_creatable->complete() method
which calls ram_backend_memory_init() so leaving it as is should be fine.
>
> static void
> host_memory_backend_alloc(HostMemoryBackend *backend, Error **errp)
> {
> Error *local_err = NULL;
> bc->memory_init(backend, &local_err);
> if (local_err != NULL) {
> error_propagate(errp, local_err);
> return;
> }
>
> ... set policy ...
> }
>
> ...
>
> Error *local_err = NULL;
> host_memory_backend_alloc(backend, &local_err);
> if (local_err != NULL) {
> error_propagate(errp, local_err);
> return NULL;
> }
>
> assert(memory_region_size(&backend->mr) != 0);
> return &backend->mr;
> }
>
[...]
