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Commit 5299edbf authored by Sandipan Das's avatar Sandipan Das Committed by Greg Kroah-Hartman
Browse files

selftests/powerpc: Fix online CPU selection 



[ Upstream commit dfa03fff86027e58c8dba5c03ae68150d4e513ad ]

The size of the CPU affinity mask must be large enough for
systems with a very large number of CPUs. Otherwise, tests
which try to determine the first online CPU by calling
sched_getaffinity() will fail. This makes sure that the size
of the allocated affinity mask is dependent on the number of
CPUs as reported by get_nprocs_conf().

Fixes: 3752e453 ("selftests/powerpc: Add tests of PMU EBBs")
Reported-by: default avatarShirisha Ganta <shiganta@in.ibm.com>
Signed-off-by: default avatarSandipan Das <sandipan@linux.ibm.com>
Reviewed-by: default avatarKamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a408c4b8e9a23bb39b539417a21eb0ff47bb5127.1596084858.git.sandipan@linux.ibm.com


Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 54127513

tools/testing/selftests/powerpc/utils.c

+25 −12
Original line number Original line Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <string.h>

#include <string.h>

#include <sys/ioctl.h>

#include <sys/ioctl.h>

#include <sys/stat.h>

#include <sys/stat.h>

#include <sys/sysinfo.h>

#include <sys/types.h>

#include <sys/types.h>

#include <sys/utsname.h>

#include <sys/utsname.h>

#include <unistd.h>

#include <unistd.h>
@@ -88,28 +89,40 @@ void *get_auxv_entry(int type) 




int pick_online_cpu(void)

int pick_online_cpu(void)

{

{

	cpu_set_t mask;

	int ncpus, cpu = -1;

	int cpu;

	cpu_set_t *mask;

	size_t size;



	ncpus = get_nprocs_conf();

	size = CPU_ALLOC_SIZE(ncpus);

	mask = CPU_ALLOC(ncpus);

	if (!mask) {

		perror("malloc");

		return -1;

	}





	CPU_ZERO(&mask);

	CPU_ZERO_S(size, mask);





	if (sched_getaffinity(0, sizeof(mask), &mask)) {

	if (sched_getaffinity(0, size, mask)) {

		perror("sched_getaffinity");

		perror("sched_getaffinity");

		return -1;

		goto done;

	}

	}





	/* We prefer a primary thread, but skip 0 */

	/* We prefer a primary thread, but skip 0 */

	for (cpu = 8; cpu < CPU_SETSIZE; cpu += 8)

	for (cpu = 8; cpu < ncpus; cpu += 8)

		if (CPU_ISSET(cpu, &mask))

		if (CPU_ISSET_S(cpu, size, mask))

			return cpu;

			goto done;





	/* Search for anything, but in reverse */

	/* Search for anything, but in reverse */

	for (cpu = CPU_SETSIZE - 1; cpu >= 0; cpu--)

	for (cpu = ncpus - 1; cpu >= 0; cpu--)

		if (CPU_ISSET(cpu, &mask))

		if (CPU_ISSET_S(cpu, size, mask))

			return cpu;

			goto done;





	printf("No cpus in affinity mask?!\n");

	printf("No cpus in affinity mask?!\n");

	return -1;



done:

	CPU_FREE(mask);

	return cpu;

}

}





bool is_ppc64le(void)

bool is_ppc64le(void)