Commit 6f7f02e7 authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds

cpusets: allow empty {cpus,mems}_allowed to be set for unpopulated cpuset

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.
Acked-by: default avatarPaul Jackson <pj@sgi.com>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: default avatarPaul Menage <menage@google.com>
Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0c28f287
......@@ -821,11 +821,22 @@ 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[0] || (buf[0] == '\n' && !buf[1])) {
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)
......@@ -918,16 +929,27 @@ 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[0] || (buf[0] == '\n' && !buf[1])) {
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;
}
......
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