| Message ID | 1435842491-131872-3-git-send-email-imammedo@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, 2 Jul 2015 15:08:11 +0200 Igor Mammedov <imammedo@redhat.com> wrote: > it became possible to use a bigger amount of memory > slots, which is used by memory hotplug for > registering hotplugged memory. > However QEMU crashes if it's used with more than ~60 > pc-dimm devices and vhost-net enabled since host kernel > in module vhost-net refuses to accept more than 64 > memory regions. > > Allow to tweak limit via max_mem_regions module paramemter > with default value set to 64 slots. Michael, what was the reason not to rise default? As much as I think I can't come up with one. Making it as module option doesn't make much sense since old userspace will crash on new kernels anyway until admins learn that there is a module option to rise limit. Rising default limit on par with kvm's will help to avoid those crashes and would allow to drop not necessary option to reduce user confusion. > > Signed-off-by: Igor Mammedov <imammedo@redhat.com> > --- > drivers/vhost/vhost.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 6488011..9a68e2e 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -29,8 +29,12 @@ > > #include "vhost.h" > > +static ushort max_mem_regions = 64; > +module_param(max_mem_regions, ushort, 0444); > +MODULE_PARM_DESC(max_mem_regions, > + "Maximum number of memory regions in memory map. (default: 64)"); > + > enum { > - VHOST_MEMORY_MAX_NREGIONS = 64, > VHOST_MEMORY_F_LOG = 0x1, > }; > > @@ -696,7 +700,7 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) > return -EFAULT; > if (mem.padding) > return -EOPNOTSUPP; > - if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS) > + if (mem.nregions > max_mem_regions) > return -E2BIG; > newmem = vhost_kvzalloc(size + mem.nregions * sizeof(*m->regions)); > if (!newmem) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 6488011..9a68e2e 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -29,8 +29,12 @@ #include "vhost.h" +static ushort max_mem_regions = 64; +module_param(max_mem_regions, ushort, 0444); +MODULE_PARM_DESC(max_mem_regions, + "Maximum number of memory regions in memory map. (default: 64)"); + enum { - VHOST_MEMORY_MAX_NREGIONS = 64, VHOST_MEMORY_F_LOG = 0x1, }; @@ -696,7 +700,7 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) return -EFAULT; if (mem.padding) return -EOPNOTSUPP; - if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS) + if (mem.nregions > max_mem_regions) return -E2BIG; newmem = vhost_kvzalloc(size + mem.nregions * sizeof(*m->regions)); if (!newmem)
it became possible to use a bigger amount of memory slots, which is used by memory hotplug for registering hotplugged memory. However QEMU crashes if it's used with more than ~60 pc-dimm devices and vhost-net enabled since host kernel in module vhost-net refuses to accept more than 64 memory regions. Allow to tweak limit via max_mem_regions module paramemter with default value set to 64 slots. Signed-off-by: Igor Mammedov <imammedo@redhat.com> --- drivers/vhost/vhost.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)