You currently cannot remove all cpus or mems from cpus_allowed or mems_allowed of a cpuset. We now allow both if there are no attached tasks.
Cc: Paul Jackson <[EMAIL PROTECTED]> Cc: Christoph Lameter <[EMAIL PROTECTED]> Signed-off-by: Paul Menage <[EMAIL PROTECTED]> Signed-off-by: David Rientjes <[EMAIL PROTECTED]> --- kernel/cpuset.c | 38 ++++++++++++++++++++++++++++++-------- 1 files changed, 30 insertions(+), 8 deletions(-) diff --git a/kernel/cpuset.c b/kernel/cpuset.c --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -822,11 +822,22 @@ static int update_cpumask(struct cpuset *cs, char *buf) return -EACCES; trialcs = *cs; - retval = cpulist_parse(buf, trialcs.cpus_allowed); - if (retval < 0) - return retval; + + /* + * We allow a cpuset's cpus_allowed to be empty; if it has attached + * tasks, we'll catch it later when we validate the change and return + * -ENOSPC. + */ + if (!*buf) { + cpus_clear(trialcs.cpus_allowed); + } else { + retval = cpulist_parse(buf, trialcs.cpus_allowed); + if (retval < 0) + return retval; + } cpus_and(trialcs.cpus_allowed, trialcs.cpus_allowed, cpu_online_map); - if (cpus_empty(trialcs.cpus_allowed)) + /* cpus_allowed cannot be empty for a cpuset with attached tasks. */ + if (atomic_read(&cs->count) && cpus_empty(trialcs.cpus_allowed)) return -ENOSPC; retval = validate_change(cs, &trialcs); if (retval < 0) @@ -919,16 +930,27 @@ static int update_nodemask(struct cpuset *cs, char *buf) return -EACCES; trialcs = *cs; - retval = nodelist_parse(buf, trialcs.mems_allowed); - if (retval < 0) - goto done; + + /* + * We allow a cpuset's mems_allowed to be empty; if it has attached + * tasks, we'll catch it later when we validate the change and return + * -ENOSPC. + */ + if (!*buf) { + nodes_clear(trialcs.mems_allowed); + } else { + retval = nodelist_parse(buf, trialcs.mems_allowed); + if (retval < 0) + goto done; + } nodes_and(trialcs.mems_allowed, trialcs.mems_allowed, node_online_map); oldmem = cs->mems_allowed; if (nodes_equal(oldmem, trialcs.mems_allowed)) { retval = 0; /* Too easy - nothing to do */ goto done; } - if (nodes_empty(trialcs.mems_allowed)) { + /* mems_allowed cannot be empty for a cpuset with attached tasks. */ + if (atomic_read(&cs->count) && nodes_empty(trialcs.mems_allowed)) { retval = -ENOSPC; goto done; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/