read_basicinfo() relies on sysfs cpu directories
"/sys/devices/system/cpu/cpu%d" with assumption that cpu
logical number %d is always sequentially assigned for all
CPUs. However, this assumption is not correct with CPU
hot-remove operation since it removes a target sysfs cpu
directory after it is ejected. As a result, lscpu may not
recognize all CPUs.
The issue can be easily reproduced on KVM or VirtualBox,
which supports CPU eject operation, as follows.
1) The system has 4 CPUs
$ lscpu -a -e
CPU NODE SOCKET CORE L1d:L1i:L2 ONLINE
0 0 0 0 0:0:0 yes
1 0 1 1 1:1:1 yes
2 0 2 2 2:2:2 yes
3 0 3 3 3:3:3 yes
2) Eject cpu2
# echo 1 > /sys/bus/acpi/devices/LNXCPU:02/eject
3) lscpu no longer recognizes cpu3 after cpu2 is ejected
$ lscpu -a -e
CPU NODE SOCKET CORE L1d:L1i:L2 ONLINE
0 0 0 0 0:0:0 yes
1 0 1 1 1:1:1 yes
The following changes are made to address this issue.
- Use maxcpus to allocate and parse bitmaps.
- Set desc->ncpu from cpu/present, which includes both on-line
and off-line CPUs.
- Add is_cpu_present() to check if a CPU is present. Ejected
CPUs are not present.
Signed-off-by: Toshi Kani <toshi.kani@xxxxxx>
---
sys-utils/lscpu.c | 53 ++++++++++++++++++++++++++++++++---------------------
1 file changed, 32 insertions(+), 21 deletions(-)
diff --git a/sys-utils/lscpu.c b/sys-utils/lscpu.c
index 25a0273..946eb41 100644
--- a/sys-utils/lscpu.c
+++ b/sys-utils/lscpu.c
@@ -150,7 +150,8 @@ struct lscpu_desc {
int dispatching; /* none, horizontal or vertical */
int mode; /* rm, lm or/and tm */
- int ncpus; /* number of CPUs */
+ int ncpus; /* number of present CPUs */
+ cpu_set_t *present; /* mask with present CPUs */
cpu_set_t *online; /* mask with online CPUs */
int nnodes; /* number of NUMA modes */
@@ -204,8 +205,11 @@ struct lscpu_modifier {
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)
+ ((_d) && (_d)->online ? \
+ CPU_ISSET_S((_cpu), CPU_ALLOC_SIZE(maxcpus), (_d)->online) : 0)
+#define is_cpu_present(_d, _cpu) \
+ ((_d) && (_d)->present ? \
+ CPU_ISSET_S((_cpu), CPU_ALLOC_SIZE(maxcpus), (_d)->present) : 0)
/*
* IDs
@@ -340,10 +344,6 @@ read_basicinfo(struct lscpu_desc *desc, struct lscpu_modifier *mod)
err(EXIT_FAILURE, _("error: uname failed"));
desc->arch = xstrdup(utsbuf.machine);
- /* count CPU(s) */
- while(path_exist(_PATH_SYS_SYSTEM "/cpu/cpu%d", desc->ncpus))
- desc->ncpus++;
-
/* details */
while (fgets(buf, sizeof(buf), fp) != NULL) {
if (lookup(buf, "vendor", &desc->vendor)) ;
@@ -391,7 +391,14 @@ read_basicinfo(struct lscpu_desc *desc, struct lscpu_modifier *mod)
if (maxcpus <= 0)
/* error or we are reading some /sys snapshot instead of the
* real /sys, let's use any crazy number... */
- maxcpus = desc->ncpus > 2048 ? desc->ncpus : 2048;
+ maxcpus = 2048;
+
+ /* get mask for present CPUs */
+ if (path_exist(_PATH_SYS_SYSTEM "/cpu/present")) {
+ size_t setsize = CPU_ALLOC_SIZE(maxcpus);
+ desc->present = path_cpulist(maxcpus, _PATH_SYS_SYSTEM "/cpu/present");
+ desc->ncpus = CPU_COUNT_S(setsize, desc->present);
+ }
/* get mask for online CPUs */
if (path_exist(_PATH_SYS_SYSTEM "/cpu/online")) {
@@ -626,16 +633,16 @@ read_topology(struct lscpu_desc *desc, int num)
*/
if (!desc->nthreads)
desc->nthreads = nbooks * nsockets * ncores * nthreads;
- /* For each map we make sure that it can have up to ncpus
+ /* For each map we make sure that it can have up to maxcpus
* entries. This is because we cannot reliably calculate the
* number of cores, sockets and books on all architectures.
* E.g. completely virtualized architectures like s390 may
* have multiple sockets of different sizes.
*/
- desc->coremaps = xcalloc(desc->ncpus, sizeof(cpu_set_t *));
- desc->socketmaps = xcalloc(desc->ncpus, sizeof(cpu_set_t *));
+ desc->coremaps = xcalloc(maxcpus, sizeof(cpu_set_t *));
+ desc->socketmaps = xcalloc(maxcpus, sizeof(cpu_set_t *));
if (book_siblings)
- desc->bookmaps = xcalloc(desc->ncpus, sizeof(cpu_set_t *));
+ desc->bookmaps = xcalloc(maxcpus, sizeof(cpu_set_t *));
}
add_cpuset_to_array(desc->socketmaps, &desc->nsockets, core_siblings);
@@ -653,7 +660,7 @@ read_polarization(struct lscpu_desc *desc, int num)
if (!path_exist(_PATH_SYS_CPU "/cpu%d/polarization", num))
return;
if (!desc->polarization)
- desc->polarization = xcalloc(desc->ncpus, sizeof(int));
+ desc->polarization = xcalloc(maxcpus, sizeof(int));
path_getstr(mode, sizeof(mode), _PATH_SYS_CPU "/cpu%d/polarization", num);
if (strncmp(mode, "vertical:low", sizeof(mode)) == 0)
desc->polarization[num] = POLAR_VLOW;
@@ -673,7 +680,7 @@ read_address(struct lscpu_desc *desc, int num)
if (!path_exist(_PATH_SYS_CPU "/cpu%d/address", num))
return;
if (!desc->addresses)
- desc->addresses = xcalloc(desc->ncpus, sizeof(int));
+ desc->addresses = xcalloc(maxcpus, sizeof(int));
desc->addresses[num] = path_getnum(_PATH_SYS_CPU "/cpu%d/address", num);
}
@@ -683,7 +690,7 @@ read_configured(struct lscpu_desc *desc, int num)
if (!path_exist(_PATH_SYS_CPU "/cpu%d/configure", num))
return;
if (!desc->configured)
- desc->configured = xcalloc(desc->ncpus, sizeof(int));
+ desc->configured = xcalloc(maxcpus, sizeof(int));
desc->configured[num] = path_getnum(_PATH_SYS_CPU "/cpu%d/configure", num);
}
@@ -756,7 +763,7 @@ read_cache(struct lscpu_desc *desc, int num)
num, i);
if (!ca->sharedmaps)
- ca->sharedmaps = xcalloc(desc->ncpus, sizeof(cpu_set_t *));
+ ca->sharedmaps = xcalloc(maxcpus, sizeof(cpu_set_t *));
add_cpuset_to_array(ca->sharedmaps, &ca->nsharedmaps, map);
}
}
@@ -982,13 +989,15 @@ print_parsable(struct lscpu_desc *desc, int cols[], int ncols,
/*
* Data
*/
- for (i = 0; i < desc->ncpus; i++) {
+ for (i = 0; i < maxcpus; i++) {
int c;
if (!mod->offline && desc->online && !is_cpu_online(desc, i))
continue;
if (!mod->online && desc->online && is_cpu_online(desc, i))
continue;
+ if (desc->present && !is_cpu_present(desc, i))
+ continue;
for (c = 0; c < ncols; c++) {
if (mod->compat && cols[c] == COL_CACHE) {
if (!desc->ncaches)
@@ -1026,7 +1035,7 @@ print_readable(struct lscpu_desc *desc, int cols[], int ncols,
tt_define_column(tt, xstrdup(data), 0, 0);
}
- for (i = 0; i < desc->ncpus; i++) {
+ for (i = 0; i < maxcpus; i++) {
int c;
struct tt_line *line;
@@ -1034,6 +1043,8 @@ print_readable(struct lscpu_desc *desc, int cols[], int ncols,
continue;
if (!mod->online && desc->online && is_cpu_online(desc, i))
continue;
+ if (desc->present && !is_cpu_present(desc, i))
+ continue;
line = tt_add_line(tt, NULL);
@@ -1117,8 +1128,8 @@ print_summary(struct lscpu_desc *desc, struct lscpu_modifier *mod)
if (!set)
err(EXIT_FAILURE, _("failed to callocate cpu set"));
CPU_ZERO_S(setsize, set);
- for (i = 0; i < desc->ncpus; i++) {
- if (!is_cpu_online(desc, i))
+ for (i = 0; i < maxcpus; i++) {
+ if (!is_cpu_online(desc, i) && is_cpu_present(desc, i))
CPU_SET_S(i, setsize, set);
}
print_cpuset(mod->hex ? _("Off-line CPU(s) mask:") :
@@ -1339,7 +1350,7 @@ int main(int argc, char *argv[])
read_basicinfo(desc, mod);
- for (i = 0; i < desc->ncpus; i++) {
+ for (i = 0; i < maxcpus; i++) {
read_topology(desc, i);
read_cache(desc, i);
read_polarization(desc, i);
--
1.7.11.7
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