[libvirt] [PATCHv3 1/4] nodeinfo: enable nodeGetCPUCount for older kernels
Since /sys/devices/system/cpu/present is not available on
older kernels like on RHEL 5.x nodeGetCPUCount will
fail there. The fallback implemented is to scan for
/sys/devices/system/cpu/cpuNN entries.
Signed-off-by: Viktor Mihajlovski <mihajlov(a)linux.vnet.ibm.com>
---
src/nodeinfo.c | 33 ++++++++++++++++++++++++++++-----
1 file changed, 28 insertions(+), 5 deletions(-)
diff --git a/src/nodeinfo.c b/src/nodeinfo.c
index e3d7cfe..cea3775 100644
--- a/src/nodeinfo.c
+++ b/src/nodeinfo.c
@@ -978,11 +978,34 @@ int
nodeGetCPUCount(void)
{
#ifdef __linux__
- /* XXX should we also work on older kernels, like RHEL5, that lack
- * cpu/present and cpu/online files? Those kernels also lack cpu
- * hotplugging, so it would be a matter of finding the largest
- * cpu/cpuNN directory, and returning NN + 1 */
- return linuxParseCPUmax(SYSFS_SYSTEM_PATH "/cpu/present");
+ /* to support older kernels, like RHEL5, that lack
+ * cpu/present we fall back to count cpu/cpuNN
+ * entries.
+ */
+ char *cpupath = NULL;
+ int i = 0;
+
+ if (virFileExists(SYSFS_SYSTEM_PATH "/cpu/present")) {
+ i = linuxParseCPUmax(SYSFS_SYSTEM_PATH "/cpu/present");
+ } else if (virFileExists(SYSFS_SYSTEM_PATH "/cpu/cpu0")) {
+ do {
+ i++;
+ VIR_FREE(cpupath);
+ if (virAsprintf(&cpupath, "%s/cpu/cpu%d",
+ SYSFS_SYSTEM_PATH, i) < 0) {
+ virReportOOMError();
+ return -1;
+ }
+ } while (virFileExists(cpupath));
+ } else {
+ /* no cpu/cpu0: we give up */
+ virReportError(VIR_ERR_NO_SUPPORT, "%s",
+ _("host cpu counting not supported on this node"));
+ return -1;
+ }
+
+ VIR_FREE(cpupath);
+ return i;
#else
virReportError(VIR_ERR_NO_SUPPORT, "%s",
_("host cpu counting not implemented on this platform"));
--
1.7.12.4