Mailing List Archive

[PATCH v4 3/5] xen/cpupool: add cpupool directories
Add /cpupool/<cpupool-id> directories to hypfs. Those are completely
dynamic, so the related hypfs access functions need to be implemented.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Dario Faggioli <dfaggioli@suse.com>
---
V2:
- added const (Jan Beulich)
- call hypfs_add_dir() in helper (Dario Faggioli)
- switch locking to enter/exit callbacks

V3:
- use generic dyndirid enter function
- const for hypfs function vector (Jan Beulich)
- drop size calculation from cpupool_dir_read() (Jan Beulich)
- check cpupool id to not exceed UINT_MAX (Jan Beulich)
- coding style (#if/#else/#endif) (Jan Beulich)
---
docs/misc/hypfs-paths.pandoc | 9 +++
xen/common/sched/cpupool.c | 104 +++++++++++++++++++++++++++++++++++
2 files changed, 113 insertions(+)

diff --git a/docs/misc/hypfs-paths.pandoc b/docs/misc/hypfs-paths.pandoc
index 6c7b2f7ee3..aaca1cdf92 100644
--- a/docs/misc/hypfs-paths.pandoc
+++ b/docs/misc/hypfs-paths.pandoc
@@ -175,6 +175,15 @@ The major version of Xen.

The minor version of Xen.

+#### /cpupool/
+
+A directory of all current cpupools.
+
+#### /cpupool/*/
+
+The individual cpupools. Each entry is a directory with the name being the
+cpupool-id (e.g. /cpupool/0/).
+
#### /params/

A directory of runtime parameters.
diff --git a/xen/common/sched/cpupool.c b/xen/common/sched/cpupool.c
index 0db7d77219..f293ba0cc4 100644
--- a/xen/common/sched/cpupool.c
+++ b/xen/common/sched/cpupool.c
@@ -13,6 +13,8 @@

#include <xen/cpu.h>
#include <xen/cpumask.h>
+#include <xen/guest_access.h>
+#include <xen/hypfs.h>
#include <xen/init.h>
#include <xen/keyhandler.h>
#include <xen/lib.h>
@@ -33,6 +35,7 @@ static int cpupool_moving_cpu = -1;
static struct cpupool *cpupool_cpu_moving = NULL;
static cpumask_t cpupool_locked_cpus;

+/* This lock nests inside sysctl or hypfs lock. */
static DEFINE_SPINLOCK(cpupool_lock);

static enum sched_gran __read_mostly opt_sched_granularity = SCHED_GRAN_cpu;
@@ -1003,12 +1006,113 @@ static struct notifier_block cpu_nfb = {
.notifier_call = cpu_callback
};

+#ifdef CONFIG_HYPFS
+
+static HYPFS_DIR_INIT(cpupool_pooldir, "%u");
+
+static int cpupool_dir_read(const struct hypfs_entry *entry,
+ XEN_GUEST_HANDLE_PARAM(void) uaddr)
+{
+ int ret = 0;
+ const struct cpupool *c;
+
+ list_for_each_entry(c, &cpupool_list, list)
+ {
+ ret = hypfs_read_dyndir_id_entry(&cpupool_pooldir, c->cpupool_id,
+ list_is_last(&c->list, &cpupool_list),
+ &uaddr);
+ if ( ret )
+ break;
+ }
+
+ return ret;
+}
+
+static unsigned int cpupool_dir_getsize(const struct hypfs_entry *entry)
+{
+ const struct cpupool *c;
+ unsigned int size = 0;
+
+ list_for_each_entry(c, &cpupool_list, list)
+ size += hypfs_dynid_entry_size(entry, c->cpupool_id);
+
+ return size;
+}
+
+static const struct hypfs_entry *cpupool_dir_enter(
+ const struct hypfs_entry *entry)
+{
+ struct hypfs_dyndir_id *data;
+
+ data = hypfs_alloc_dyndata(struct hypfs_dyndir_id);
+ if ( !data )
+ return ERR_PTR(-ENOMEM);
+ data->id = CPUPOOLID_NONE;
+
+ spin_lock(&cpupool_lock);
+
+ return entry;
+}
+
+static void cpupool_dir_exit(const struct hypfs_entry *entry)
+{
+ spin_unlock(&cpupool_lock);
+
+ hypfs_free_dyndata();
+}
+
+static struct hypfs_entry *cpupool_dir_findentry(
+ const struct hypfs_entry_dir *dir, const char *name, unsigned int name_len)
+{
+ unsigned long id;
+ const char *end;
+ struct cpupool *cpupool;
+
+ id = simple_strtoul(name, &end, 10);
+ if ( end != name + name_len || id > UINT_MAX )
+ return ERR_PTR(-ENOENT);
+
+ cpupool = __cpupool_find_by_id(id, true);
+
+ if ( !cpupool )
+ return ERR_PTR(-ENOENT);
+
+ return hypfs_gen_dyndir_id_entry(&cpupool_pooldir, id, cpupool);
+}
+
+static const struct hypfs_funcs cpupool_dir_funcs = {
+ .enter = cpupool_dir_enter,
+ .exit = cpupool_dir_exit,
+ .read = cpupool_dir_read,
+ .write = hypfs_write_deny,
+ .getsize = cpupool_dir_getsize,
+ .findentry = cpupool_dir_findentry,
+};
+
+static HYPFS_DIR_INIT_FUNC(cpupool_dir, "cpupool", &cpupool_dir_funcs);
+
+static void cpupool_hypfs_init(void)
+{
+ hypfs_add_dir(&hypfs_root, &cpupool_dir, true);
+ hypfs_add_dyndir(&cpupool_dir, &cpupool_pooldir);
+}
+
+#else /* CONFIG_HYPFS */
+
+static void cpupool_hypfs_init(void)
+{
+}
+
+#endif /* CONFIG_HYPFS */
+
static int __init cpupool_init(void)
{
unsigned int cpu;

cpupool_gran_init();

+ cpupool_hypfs_init();
+
cpupool0 = cpupool_create(0, 0);
BUG_ON(IS_ERR(cpupool0));
cpupool_put(cpupool0);
--
2.26.2