[Qemu-devel] [PATCH] backends/hostmem: Ignore ENOSYS while setting MPOL_DEFAULT

[Qemu-devel] [PATCH] backends/hostmem: Ignore ENOSYS while setting MPOL_DEFAULT

[Pavel Fedin]

Currently hostmem backend fails if CONFIG_NUMA is enabled for the qemu
(default), but NUMA is not supported by the kernel. This makes it
impossible to use ivshmem in such configurations.

This patch fixes the problem by ignoring ENOSYS error if policy is set to
MPOL_DEFAULT. This way the code behaves in the same way as if CONFIG_NUMA
was not defined. qemu will still fail if the user specifies some other
policy, so that the user knows it.

Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
---
 backends/hostmem.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/backends/hostmem.c b/backends/hostmem.c
index 41ba2af..826141b 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -313,9 +313,11 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
         assert(maxnode <= MAX_NODES);
         if (mbind(ptr, sz, backend->policy,
                   maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
-            error_setg_errno(errp, errno,
+            if ((backend->policy != MPOL_DEFAULT) || (errno != ENOSYS)) {
+                error_setg_errno(errp, errno,
                              "cannot bind memory to host NUMA nodes");
-            return;
+                return;
+            }
         }
 #endif
         /* Preallocate memory after the NUMA policy has been instantiated.
-- 
1.9.5.msysgit.0

Re: [Qemu-devel] [PATCH] backends/hostmem: Ignore ENOSYS while setting MPOL_DEFAULT

[Paolo Bonzini]

On 27/10/2015 13:11, Pavel Fedin wrote:
> +            if ((backend->policy != MPOL_DEFAULT) || (errno != ENOSYS)) {

Can you remove parentheses around conditions?

Paolo

> +                error_setg_errno(errp, errno,
>                               "cannot bind memory to host NUMA nodes");
> -            return;
> +                return;

[Qemu-devel] [PATCH] backends/hostmem: Ignore ENOSYS while setting MPOL_DEFAULT

[Pavel Fedin]

Currently hostmem backend fails if CONFIG_NUMA is enabled for the qemu
(default), but NUMA is not supported by the kernel. This makes it
impossible to use ivshmem in such configurations.

This patch fixes the problem by ignoring ENOSYS error if policy is set to
MPOL_DEFAULT. This way the code behaves in the same way as if CONFIG_NUMA
was not defined. qemu will still fail if the user specifies some other
policy, so that the user knows it.

Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
---
 backends/hostmem.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/backends/hostmem.c b/backends/hostmem.c
index 41ba2af..94a4ac0 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -313,9 +313,11 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
         assert(maxnode <= MAX_NODES);
         if (mbind(ptr, sz, backend->policy,
                   maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
-            error_setg_errno(errp, errno,
+            if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
+                error_setg_errno(errp, errno,
                              "cannot bind memory to host NUMA nodes");
-            return;
+                return;
+            }
         }
 #endif
         /* Preallocate memory after the NUMA policy has been instantiated.
-- 
1.9.5.msysgit.0

Re: [Qemu-devel] [PATCH] backends/hostmem: Ignore ENOSYS while setting MPOL_DEFAULT

[Pavel Fedin]

 Sorry, guys, i forgot to add "v2" and simply sent the mail. Log is:

v1 => v2:
- Removed unnecessary parenthesis

Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia

> -----Original Message-----
> From: qemu-devel-bounces+p.fedin=samsung.com@nongnu.org [mailto:qemu-devel-
> bounces+p.fedin=samsung.com@nongnu.org] On Behalf Of Pavel Fedin
> Sent: Tuesday, October 27, 2015 3:52 PM
> To: qemu-devel@nongnu.org
> Cc: 'Paolo Bonzini'; 'Eduardo Habkost'
> Subject: [Qemu-devel] [PATCH] backends/hostmem: Ignore ENOSYS while setting MPOL_DEFAULT
> 
> Currently hostmem backend fails if CONFIG_NUMA is enabled for the qemu
> (default), but NUMA is not supported by the kernel. This makes it
> impossible to use ivshmem in such configurations.
> 
> This patch fixes the problem by ignoring ENOSYS error if policy is set to
> MPOL_DEFAULT. This way the code behaves in the same way as if CONFIG_NUMA
> was not defined. qemu will still fail if the user specifies some other
> policy, so that the user knows it.
> 
> Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
> ---
>  backends/hostmem.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/backends/hostmem.c b/backends/hostmem.c
> index 41ba2af..94a4ac0 100644
> --- a/backends/hostmem.c
> +++ b/backends/hostmem.c
> @@ -313,9 +313,11 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
>          assert(maxnode <= MAX_NODES);
>          if (mbind(ptr, sz, backend->policy,
>                    maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
> -            error_setg_errno(errp, errno,
> +            if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
> +                error_setg_errno(errp, errno,
>                               "cannot bind memory to host NUMA nodes");
> -            return;
> +                return;
> +            }
>          }
>  #endif
>          /* Preallocate memory after the NUMA policy has been instantiated.
> --
> 1.9.5.msysgit.0
> 

Re: [Qemu-devel] [PATCH] backends/hostmem: Ignore ENOSYS while setting MPOL_DEFAULT

[Eduardo Habkost]

On Tue, Oct 27, 2015 at 03:51:31PM +0300, Pavel Fedin wrote:
> Currently hostmem backend fails if CONFIG_NUMA is enabled for the qemu
> (default), but NUMA is not supported by the kernel. This makes it
> impossible to use ivshmem in such configurations.
> 
> This patch fixes the problem by ignoring ENOSYS error if policy is set to
> MPOL_DEFAULT. This way the code behaves in the same way as if CONFIG_NUMA
> was not defined. qemu will still fail if the user specifies some other
> policy, so that the user knows it.
> 
> Signed-off-by: Pavel Fedin <p.fedin@samsung.com>

Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>

Thanks. Applied to numa tree, with the following indentation fix:

diff --git a/backends/hostmem.c b/backends/hostmem.c
index 94a4ac0..1b4eb45 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -315,7 +315,7 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
                   maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
             if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
                 error_setg_errno(errp, errno,
-                             "cannot bind memory to host NUMA nodes");
+                                 "cannot bind memory to host NUMA nodes");
                 return;
             }
         }

> ---
>  backends/hostmem.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/backends/hostmem.c b/backends/hostmem.c
> index 41ba2af..94a4ac0 100644
> --- a/backends/hostmem.c
> +++ b/backends/hostmem.c
> @@ -313,9 +313,11 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
>          assert(maxnode <= MAX_NODES);
>          if (mbind(ptr, sz, backend->policy,
>                    maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
> -            error_setg_errno(errp, errno,
> +            if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
> +                error_setg_errno(errp, errno,
>                               "cannot bind memory to host NUMA nodes");
> -            return;
> +                return;
> +            }
>          }
>  #endif
>          /* Preallocate memory after the NUMA policy has been instantiated.
> -- 
> 1.9.5.msysgit.0
> 
> 

-- 
Eduardo