Re: [Qemu-devel] [PATCH V9 07/12] NUMA: parse guest numa nodes memory policy

[Andrew Jones <drjones@redhat.com>]

----- Original Message -----
> On 08/23/2013 10:11 PM, Andrew Jones wrote:
> > 
> > 
> > ----- Original Message -----
> >> The memory policy setting format is like:
> >>     policy={default|membind|interleave|preferred}[,relative=true],host-nodes=N-N
> >> And we are adding this setting as a suboption of "-numa mem,",
> >> the memory policy then can be set like following:
> >>     -numa node,nodeid=0,cpus=0 \
> >>     -numa node,nodeid=1,cpus=1 \
> >>     -numa mem,nodeid=0,size=1G,policy=membind,host-nodes=0-1 \
> >>     -numa
> >>     mem,nodeid=1,size=1G,policy=interleave,relative=true,host-nodes=1
> >>
> >> Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
> >> ---
> >>  include/sysemu/sysemu.h |  3 +++
> >>  numa.c                  | 13 +++++++++++++
> >>  qapi-schema.json        | 31 +++++++++++++++++++++++++++++--
> >>  vl.c                    |  3 +++
> >>  4 files changed, 48 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
> >> index b683d08..81d16a5 100644
> >> --- a/include/sysemu/sysemu.h
> >> +++ b/include/sysemu/sysemu.h
> >> @@ -134,6 +134,9 @@ extern int nb_numa_mem_nodes;
> >>  typedef struct node_info {
> >>      uint64_t node_mem;
> >>      DECLARE_BITMAP(node_cpu, MAX_CPUMASK_BITS);
> >> +    DECLARE_BITMAP(host_mem, MAX_CPUMASK_BITS);
> >> +    NumaNodePolicy policy;
> >> +    bool relative;
> >>  } NodeInfo;
> >>  extern NodeInfo numa_info[MAX_NODES];
> >>  extern QemuOptsList qemu_numa_opts;
> >> diff --git a/numa.c b/numa.c
> >> index 3e2dfc1..4ccc6cb 100644
> >> --- a/numa.c
> >> +++ b/numa.c
> >> @@ -74,6 +74,7 @@ static int numa_mem_parse(NumaMemOptions *opts)
> >>  {
> >>      uint16_t nodenr;
> >>      uint64_t mem_size;
> >> +    uint16List *nodes;
> >>  
> >>      if (opts->has_nodeid) {
> >>          nodenr = opts->nodeid;
> >> @@ -91,6 +92,18 @@ static int numa_mem_parse(NumaMemOptions *opts)
> >>          numa_info[nodenr].node_mem = mem_size;
> >>      }
> >>  
> >> +    if (opts->has_policy) {
> >> +        numa_info[nodenr].policy = opts->policy;
> >> +    }
> >> +
> >> +    if (opts->has_relative) {
> >> +        numa_info[nodenr].relative = opts->relative;
> >> +    }
> >> +
> >> +    for (nodes = opts->host_nodes; nodes; nodes = nodes->next) {
> >> +        bitmap_set(numa_info[nodenr].host_mem, nodes->value, 1);
> >> +    }
> >> +
> >>      return 0;
> >>  }
> >>  
> >> diff --git a/qapi-schema.json b/qapi-schema.json
> >> index 11851a1..650741f 100644
> >> --- a/qapi-schema.json
> >> +++ b/qapi-schema.json
> >> @@ -3806,6 +3806,24 @@
> >>     '*mem':    'str' }}
> >>  
> >>  ##
> >> +# @NumaNodePolicy
> >> +#
> >> +# NUMA node policy types
> >> +#
> >> +# @default: restore default policy, remove any nondefault policy
> >> +#
> >> +# @membind: a strict policy that restricts memory allocation to the
> >> +#           nodes specified
> >> +#
> >> +# @interleave: the page allocations is interleaved across the set
> >> +#              of nodes specified
> >> +#
> >> +# @preferred: set the preferred node for allocation
> >> +##
> >> +{ 'enum': 'NumaNodePolicy',
> >> +  'data': [ 'default', 'membind', 'interleave', 'preferred' ] }
> >> +
> >> +##
> >>  # @NumaMemOptions
> >>  #
> >>  # Set memory information of guest NUMA node. (for OptsVisitor)
> >> @@ -3814,9 +3832,18 @@
> >>  #
> >>  # @size: #optional memory size of this node
> >>  #
> >> +# @policy: #optional memory policy of this node
> >> +#
> >> +# @relative: #optional if the nodes specified are relative
> >> +#
> >> +# @host-nodes: #optional host nodes for its memory policy
> >> +#
> >>  # Since 1.7
> >>  ##
> >>  { 'type': 'NumaMemOptions',
> >>    'data': {
> >> -   '*nodeid': 'uint16',
> >> -   '*size':   'size' }}
> >> +   '*nodeid':     'uint16',
> >> +   '*size':       'size',
> >> +   '*policy':     'NumaNodePolicy',
> >> +   '*relative':   'bool',
> >> +   '*host-nodes': ['uint16'] }}
> >> diff --git a/vl.c b/vl.c
> >> index 2377b67..91b0d76 100644
> >> --- a/vl.c
> >> +++ b/vl.c
> >> @@ -2888,6 +2888,9 @@ int main(int argc, char **argv, char **envp)
> >>      for (i = 0; i < MAX_NODES; i++) {
> >>          numa_info[i].node_mem = 0;
> >>          bitmap_zero(numa_info[i].node_cpu, MAX_CPUMASK_BITS);
> >> +        bitmap_zero(numa_info[i].host_mem, MAX_CPUMASK_BITS);
> > 
> > Shouldn't the bitmap size of host_mem be MAX_NODES? If so, and you
> 
> MAX_NODES is for guest numa nodes number, but this bitmap is for host
> numa nodes. AFAIK, this MAX_NODES is not big enough for host nodes number,
> the default host kernel NODES_SHIFT is 9.

MAX_CPUMASK_BITS == 255 is also too small for a default node shift of 9.
You have to pick something, and then manage that limit. I think MAX_NODES
== 64 will be big enough for quite some time, but libnuma chooses 128 (see
/usr/include/numa.h:NUMA_NUM_NODES). So maybe we can bump MAX_NODES up to
128? You can also add a warning for when you detect starting on a machine
that has more than MAX_NODES nodes.

drew

> 
> Thanks,
> Wanlong Gao
> 
> > change it, then make sure the find_last_bit() call also gets
> > updated in patch 8/12, and anywhere else needed.
> > 
> > drew
> > 
> >> +        numa_info[i].policy = NUMA_NODE_POLICY_DEFAULT;
> >> +        numa_info[i].relative = false;
> >>      }
> >>  
> >>      nb_numa_nodes = 0;
> >> --
> >> 1.8.4.rc4
> >>
> >>
> >>
> > 
> 
>