Re: [libvirt] [PATCH 1/3 V6] add nodeGetCPUmap() for getting available CPU IDs in a cpumap.

From: KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com&gt; Changelog: - fixed typos. - fixed string scan routine. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com&gt; Signed-off-by: Lai Jiangshan <laijs(a)cn.fujitsu.com&gt; --- src/libvirt_private.syms | 1 + src/nodeinfo.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++ src/nodeinfo.h | 3 + 3 files changed, 96 insertions(+), 0 deletions(-) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index 0c22dec..6e99243 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -792,6 +792,7 @@ virNodeDeviceObjUnlock; # nodeinfo.h nodeCapsInitNUMA; +nodeGetCPUmap; nodeGetCPUStats; nodeGetCellsFreeMemory; nodeGetFreeMemory; diff --git a/src/nodeinfo.c b/src/nodeinfo.c index e0b66f7..fc1aaea 100644 --- a/src/nodeinfo.c +++ b/src/nodeinfo.c @@ -31,6 +31,7 @@ #include <dirent.h> #include <sys/utsname.h> #include <sched.h> +#include <conf/domain_conf.h> #if HAVE_NUMACTL # define NUMA_VERSION1_COMPATIBILITY 1 @@ -569,6 +570,73 @@ int linuxNodeGetMemoryStats(FILE *meminfo, cleanup: return ret; } + +/* + * Linux maintains cpu bit map. For example, if cpuid=5's flag is not set + * and max cpu is 7. The map file shows 0-4,6-7. This function parses + * it and returns cpumap. + */ +static const char * +linuxParseCPUmap(int *max_cpuid, const char *path) +{ + FILE *fp; + char *map = NULL; + char *str = NULL; + size_t size = 128, pos = 0; + int max_id, i; + + fp = fopen(path, "r"); + if (!fp) { + virReportSystemError(errno, _("cannot open %s"), path); + goto error; + } + + if (VIR_ALLOC_N(str, size) < 0) { + virReportOOMError(); + goto error; + } + for (;;) { + pos += fread(str + pos, 1, size - pos, fp); + if (pos < size) + break; + + size = size << 1; + if (VIR_REALLOC_N(str, size) < 0) { + virReportOOMError(); + goto error; + } + } + if (pos == 0) { + virReportSystemError(errno, _("cannot read from %s"), path); + goto error; + } + str[pos - 1] = 0; + + if (VIR_ALLOC_N(map, VIR_DOMAIN_CPUMASK_LEN) < 0) { + virReportOOMError(); + goto error; + } + if (virDomainCpuSetParse(str, 0, map, + VIR_DOMAIN_CPUMASK_LEN) < 0) { + goto error; + } + + for (i = 0; i < VIR_DOMAIN_CPUMASK_LEN; i++) { + if (map[i]) { + max_id = i; + } + } + *max_cpuid = max_id; + + VIR_FORCE_FCLOSE(fp); + return map; + +error: + VIR_FORCE_FCLOSE(fp); + VIR_FREE(str); + VIR_FREE(map); + return NULL; +} #endif int nodeGetInfo(virConnectPtr conn ATTRIBUTE_UNUSED, virNodeInfoPtr nodeinfo) { @@ -712,6 +780,30 @@ int nodeGetMemoryStats(virConnectPtr conn ATTRIBUTE_UNUSED, #endif } +const char * +nodeGetCPUmap(virConnectPtr conn ATTRIBUTE_UNUSED, + int *max_id ATTRIBUTE_UNUSED, + const char *mapname ATTRIBUTE_UNUSED) +{ +#ifdef __linux__ + char *path; + const char *cpumap; + + if (virAsprintf(&path, CPU_SYS_PATH "/%s", mapname) < 0) { + virReportOOMError(); + return NULL; + } + + cpumap = linuxParseCPUmap(max_id, path); + VIR_FREE(path); + return cpumap; +#else + nodeReportError(VIR_ERR_NO_SUPPORT, "%s", + _("node cpumap not implemented on this platform")); + return -1; +#endif +} + #if HAVE_NUMACTL # if LIBNUMA_API_VERSION <= 1 # define NUMA_MAX_N_CPUS 4096 diff --git a/src/nodeinfo.h b/src/nodeinfo.h index 4766152..852e19d 100644 --- a/src/nodeinfo.h +++ b/src/nodeinfo.h @@ -46,4 +46,7 @@ int nodeGetCellsFreeMemory(virConnectPtr conn, int maxCells); unsigned long long nodeGetFreeMemory(virConnectPtr conn); +const char *nodeGetCPUmap(virConnectPtr conn, + int *max_id, + const char *mapname); #endif /* __VIR_NODEINFO_H__*/