lscpu: support offline CPUs

 # echo 0 >/sys/devices/system/cpu/cpu3/online
 # echo 0 >/sys/devices/system/cpu/cpu2/online

 # grep processor /proc/cpuinfo
 processor       : 0
 processor       : 1

 # lscpu
 lscpu: error: cannot open
 /sys/devices/system/cpu/cpu2/cache/index0/shared_cpu_map: No such file or directory

This patch also add a new "On-line CPU(s):" line to the lscpu(1)
output.

Addresses: http://bugzilla.redhat.com/show_bug.cgi?id=623012
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/sys-utils/lscpu.c b/sys-utils/lscpu.c
index 74f5e781c92212acd00db084e9f210259a665461..eff655c4dbfa5b3d385406352d96beaf176ebef7 100644 (file)
--- a/sys-utils/lscpu.c
+++ b/sys-utils/lscpu.c
@@ -101,6 +101,7 @@ struct lscpu_desc {
        int     mode;           /* rm, lm or/and tm */
 
        int             ncpus;          /* number of CPUs */
+       cpu_set_t       *online;        /* mask with online CPUs */
 
        int             nnodes;         /* number of NUMA modes */
        cpu_set_t       **nodemaps;     /* array with NUMA nodes */
@@ -125,6 +126,10 @@ static size_t sysrootlen;
 static char pathbuf[PATH_MAX];
 static int maxcpus;            /* size in bits of kernel cpu mask */
 
+#define is_cpu_online(_d, _cpu) \
+               ((_d) && (_d)->online ? \
+                       CPU_ISSET_S((_cpu), CPU_ALLOC_SIZE(maxcpus), (_d)->online) : 0)
+
 static FILE *path_fopen(const char *mode, int exit_on_err, const char *path, ...)
                __attribute__ ((__format__ (__printf__, 3, 4)));
 static void path_getstr(char *result, size_t len, const char *path, ...)
@@ -235,17 +240,14 @@ xstrdup(const char *str)
 }
 
 static cpu_set_t *
-path_cpuset(const char *path, ...)
+path_cpuparse(int islist, const char *path, va_list ap)
 {
        FILE *fd;
-       va_list ap;
        cpu_set_t *set;
        size_t setsize, len = maxcpus * 7;
        char buf[len];
 
-       va_start(ap, path);
        fd = path_vfopen("r", 1, path, ap);
-       va_end(ap);
 
        if (!fgets(buf, len, fd))
                err(EXIT_FAILURE, _("failed to read: %s"), pathbuf);
@@ -259,8 +261,38 @@ path_cpuset(const char *path, ...)
        if (!set)
                err(EXIT_FAILURE, _("failed to callocate cpu set"));
 
-       if (cpumask_parse(buf, set, setsize))
-               errx(EXIT_FAILURE, _("failed to parse CPU mask %s"), buf);
+       if (islist) {
+               if (cpulist_parse(buf, set, setsize))
+                       errx(EXIT_FAILURE, _("failed to parse CPU list %s"), buf);
+       } else {
+               if (cpumask_parse(buf, set, setsize))
+                       errx(EXIT_FAILURE, _("failed to parse CPU mask %s"), buf);
+       }
+       return set;
+}
+
+static cpu_set_t *
+path_cpuset(const char *path, ...)
+{
+       va_list ap;
+       cpu_set_t *set;
+
+       va_start(ap, path);
+       set = path_cpuparse(0, path, ap);
+       va_end(ap);
+
+       return set;
+}
+
+static cpu_set_t *
+path_cpulist(const char *path, ...)
+{
+       va_list ap;
+       cpu_set_t *set;
+
+       va_start(ap, path);
+       set = path_cpuparse(1, path, ap);
+       va_end(ap);
 
        return set;
 }
@@ -365,6 +397,9 @@ read_basicinfo(struct lscpu_desc *desc)
                /* we are reading some /sys snapshot instead of the real /sys,
                 * let's use any crazy number... */
                maxcpus = desc->ncpus > 2048 ? desc->ncpus : 2048;
+
+       /* get mask for online CPUs */
+       desc->online = path_cpulist(_PATH_SYS_SYSTEM "/cpu/online");
 }
 
 static int
@@ -523,7 +558,8 @@ read_topology(struct lscpu_desc *desc, int num)
                                        "/cpu%d/topology/thread_siblings", num);
        core_siblings = path_cpuset(_PATH_SYS_CPU
                                        "/cpu%d/topology/core_siblings", num);
-       if (num == 0) {
+
+       if (!desc->coremaps) {
                int ncores, nsockets, nthreads;
                size_t setsize = CPU_ALLOC_SIZE(maxcpus);
 
@@ -563,7 +599,7 @@ read_cache(struct lscpu_desc *desc, int num)
        char buf[256];
        int i;
 
-       if (num == 0) {
+       if (!desc->ncaches) {
                while(path_exist(_PATH_SYS_SYSTEM "/cpu/cpu%d/cache/index%d",
                                        num, desc->ncaches))
                        desc->ncaches++;
@@ -670,6 +706,9 @@ print_parsable(struct lscpu_desc *desc)
 
        for (i = 0; i < desc->ncpus; i++) {
 
+               if (!is_cpu_online(desc, i))
+                       continue;
+
                /* #CPU */
                printf("%d", i);
 
@@ -734,6 +773,7 @@ print_readable(struct lscpu_desc *desc)
 {
        char buf[512];
        int i;
+       size_t setsize = CPU_ALLOC_SIZE(maxcpus);
 
        print_s(_("Architecture:"), desc->arch);
 
@@ -757,6 +797,7 @@ print_readable(struct lscpu_desc *desc)
        }
 
        print_n(_("CPU(s):"), desc->ncpus);
+       print_n(_("On-line CPU(s):"), CPU_COUNT_S(setsize, desc->online));
 
        if (desc->nsockets) {
                print_n(_("Thread(s) per core:"), desc->nthreads / desc->ncores);
@@ -806,7 +847,7 @@ print_readable(struct lscpu_desc *desc)
                        print_s(buf, cpulist_create(
                                                setbuf, setbuflen,
                                                desc->nodemaps[i],
-                                               CPU_ALLOC_SIZE(maxcpus)));
+                                               setsize));
                }
        }
 }
@@ -861,6 +902,8 @@ int main(int argc, char *argv[])
        read_basicinfo(desc);
 
        for (i = 0; i < desc->ncpus; i++) {
+               if (!is_cpu_online(desc, i))
+                       continue;
                read_topology(desc, i);
                read_cache(desc, i);
        }