On Thu, Mar 26, 2015 at 12:48:13AM -0400, Wei Huang wrote:
Current libvirt can only handle up to 1024 thread siblings when it reads Linux sysfs topology/thread_siblings. This isn't enough for Linux distributions that support a large value. This patch fixes the problem by using VIR_ALLOC()/VIR_FREE(), instead of using a fixed-size (1024) local char array. In the meanwhile SYSFS_THREAD_SIBLINGS_LIST_LENGTH_MAX is increased to 8192 which should be large enough for a foreseeable future.
Signed-off-by: Wei Huang <wei@redhat.com> --- src/nodeinfo.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/src/nodeinfo.c b/src/nodeinfo.c index 34d27a6..66dc7ef 100644 --- a/src/nodeinfo.c +++ b/src/nodeinfo.c @@ -287,7 +287,7 @@ freebsdNodeGetMemoryStats(virNodeMemoryStatsPtr params, # define PROCSTAT_PATH "/proc/stat" # define MEMINFO_PATH "/proc/meminfo" # define SYSFS_MEMORY_SHARED_PATH "/sys/kernel/mm/ksm" -# define SYSFS_THREAD_SIBLINGS_LIST_LENGTH_MAX 1024 +# define SYSFS_THREAD_SIBLINGS_LIST_LENGTH_MAX 8192
There is thread_siblings_list, which contains a range: 22-23 and thread_siblings file has all the bits set: 00c00000 For the second one, the 1024-byte buffer should be enough for 16368 possible siblings. For the first one, the results depend on the topology - if the sibling ranges are contiguous, even million CPUs should fit there. For the worst case, when every other cpu is a sibling, the second file is more space-efficient. I'm OK with using the same limit for both (8k seems sufficiently large), but I would like to know: Which one is the file that failed to parse in your case? I think both virNodeCountThreadSiblings and virNodeGetSiblingsList could be rewritten to share some code and only look at one of the sysfs files. The question is - which one? Jan