From: Rik van Riel <riel@xxxxxxxxxx>
The previous patch makes it so the code skips over isolcpus when
building scheduler load balancing domains. This makes it hard to
see for a user which of the CPUs in a cpuset are participating in
load balancing, and which ones are isolated cpus.
Add a cpuset.isolcpus file with info on which cpus in a cpuset are
isolated CPUs.
This file is read-only for now. In the future we could extend things
so isolcpus can be changed at run time, for the root (system wide)
cpuset only.
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Clark Williams <williams@xxxxxxxxxx>
Cc: Li Zefan <lizefan@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Luiz Capitulino <lcapitulino@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Mike Galbraith <umgwanakikbuti@xxxxxxxxx>
Cc: cgroups@xxxxxxxxxxxxxxx
Signed-off-by: Rik van Riel <riel@xxxxxxxxxx>
---
kernel/cpuset.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index b544e5229d99..5462e1ca90bd 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1563,6 +1563,7 @@ typedef enum {
FILE_MEMORY_PRESSURE,
FILE_SPREAD_PAGE,
FILE_SPREAD_SLAB,
+ FILE_ISOLCPUS,
} cpuset_filetype_t;
static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
@@ -1704,6 +1705,16 @@ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
return retval ?: nbytes;
}
+/* protected by the lock in cpuset_common_seq_show */
+static cpumask_var_t print_isolated_cpus;
+
+static void cpuset_seq_print_isolcpus(struct seq_file *sf, struct cpuset *cs)
+{
+ cpumask_and(print_isolated_cpus, cs->cpus_allowed, cpu_isolated_map);
+
+ seq_printf(sf, "%*pbl\n", cpumask_pr_args(print_isolated_cpus));
+}
+
/*
* These ascii lists should be read in a single call, by using a user
* buffer large enough to hold the entire map. If read in smaller
@@ -1733,6 +1744,9 @@ static int cpuset_common_seq_show(struct seq_file *sf, void *v)
case FILE_EFFECTIVE_MEMLIST:
seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->effective_mems));
break;
+ case FILE_ISOLCPUS:
+ cpuset_seq_print_isolcpus(sf, cs);
+ break;
default:
ret = -EINVAL;
}
@@ -1893,6 +1907,12 @@ static struct cftype files[] = {
.private = FILE_MEMORY_PRESSURE_ENABLED,
},
+ {
+ .name = "isolcpus",
+ .seq_show = cpuset_common_seq_show,
+ .private = FILE_ISOLCPUS,
+ },
+
{ } /* terminate */
};
@@ -2070,6 +2090,8 @@ int __init cpuset_init(void)
BUG();
if (!alloc_cpumask_var(&top_cpuset.effective_cpus, GFP_KERNEL))
BUG();
+ if (!alloc_cpumask_var(&print_isolated_cpus, GFP_KERNEL))
+ BUG();
cpumask_setall(top_cpuset.cpus_allowed);
nodes_setall(top_cpuset.mems_allowed);
--
2.1.0
--
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