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-rw-r--r--mm/vmpressure.c122
1 files changed, 93 insertions, 29 deletions
diff --git a/mm/vmpressure.c b/mm/vmpressure.c
index ce0618bfa8d0..85350ce2d25d 100644
--- a/mm/vmpressure.c
+++ b/mm/vmpressure.c
@@ -93,12 +93,25 @@ enum vmpressure_levels {
VMPRESSURE_NUM_LEVELS,
};
+enum vmpressure_modes {
+ VMPRESSURE_NO_PASSTHROUGH = 0,
+ VMPRESSURE_HIERARCHY,
+ VMPRESSURE_LOCAL,
+ VMPRESSURE_NUM_MODES,
+};
+
static const char * const vmpressure_str_levels[] = {
[VMPRESSURE_LOW] = "low",
[VMPRESSURE_MEDIUM] = "medium",
[VMPRESSURE_CRITICAL] = "critical",
};
+static const char * const vmpressure_str_modes[] = {
+ [VMPRESSURE_NO_PASSTHROUGH] = "default",
+ [VMPRESSURE_HIERARCHY] = "hierarchy",
+ [VMPRESSURE_LOCAL] = "local",
+};
+
static enum vmpressure_levels vmpressure_level(unsigned long pressure)
{
if (pressure >= vmpressure_level_critical)
@@ -141,27 +154,31 @@ out:
struct vmpressure_event {
struct eventfd_ctx *efd;
enum vmpressure_levels level;
+ enum vmpressure_modes mode;
struct list_head node;
};
static bool vmpressure_event(struct vmpressure *vmpr,
- enum vmpressure_levels level)
+ const enum vmpressure_levels level,
+ bool ancestor, bool signalled)
{
struct vmpressure_event *ev;
- bool signalled = false;
+ bool ret = false;
mutex_lock(&vmpr->events_lock);
-
list_for_each_entry(ev, &vmpr->events, node) {
- if (level >= ev->level) {
- eventfd_signal(ev->efd, 1);
- signalled = true;
- }
+ if (ancestor && ev->mode == VMPRESSURE_LOCAL)
+ continue;
+ if (signalled && ev->mode == VMPRESSURE_NO_PASSTHROUGH)
+ continue;
+ if (level < ev->level)
+ continue;
+ eventfd_signal(ev->efd, 1);
+ ret = true;
}
-
mutex_unlock(&vmpr->events_lock);
- return signalled;
+ return ret;
}
static void vmpressure_work_fn(struct work_struct *work)
@@ -170,6 +187,8 @@ static void vmpressure_work_fn(struct work_struct *work)
unsigned long scanned;
unsigned long reclaimed;
enum vmpressure_levels level;
+ bool ancestor = false;
+ bool signalled = false;
spin_lock(&vmpr->sr_lock);
/*
@@ -194,12 +213,9 @@ static void vmpressure_work_fn(struct work_struct *work)
level = vmpressure_calc_level(scanned, reclaimed);
do {
- if (vmpressure_event(vmpr, level))
- break;
- /*
- * If not handled, propagate the event upward into the
- * hierarchy.
- */
+ if (vmpressure_event(vmpr, level, ancestor, signalled))
+ signalled = true;
+ ancestor = true;
} while ((vmpr = vmpressure_parent(vmpr)));
}
@@ -326,17 +342,40 @@ void vmpressure_prio(gfp_t gfp, struct mem_cgroup *memcg, int prio)
vmpressure(gfp, memcg, true, vmpressure_win, 0);
}
+static enum vmpressure_levels str_to_level(const char *arg)
+{
+ enum vmpressure_levels level;
+
+ for (level = 0; level < VMPRESSURE_NUM_LEVELS; level++)
+ if (!strcmp(vmpressure_str_levels[level], arg))
+ return level;
+ return -1;
+}
+
+static enum vmpressure_modes str_to_mode(const char *arg)
+{
+ enum vmpressure_modes mode;
+
+ for (mode = 0; mode < VMPRESSURE_NUM_MODES; mode++)
+ if (!strcmp(vmpressure_str_modes[mode], arg))
+ return mode;
+ return -1;
+}
+
+#define MAX_VMPRESSURE_ARGS_LEN (strlen("critical") + strlen("hierarchy") + 2)
+
/**
* vmpressure_register_event() - Bind vmpressure notifications to an eventfd
* @memcg: memcg that is interested in vmpressure notifications
* @eventfd: eventfd context to link notifications with
- * @args: event arguments (used to set up a pressure level threshold)
+ * @args: event arguments (pressure level threshold, optional mode)
*
* This function associates eventfd context with the vmpressure
* infrastructure, so that the notifications will be delivered to the
- * @eventfd. The @args parameter is a string that denotes pressure level
- * threshold (one of vmpressure_str_levels, i.e. "low", "medium", or
- * "critical").
+ * @eventfd. The @args parameter is a comma-delimited string that denotes a
+ * pressure level threshold (one of vmpressure_str_levels, i.e. "low", "medium",
+ * or "critical") and an optional mode (one of vmpressure_str_modes, i.e.
+ * "hierarchy" or "local").
*
* To be used as memcg event method.
*/
@@ -345,28 +384,53 @@ int vmpressure_register_event(struct mem_cgroup *memcg,
{
struct vmpressure *vmpr = memcg_to_vmpressure(memcg);
struct vmpressure_event *ev;
- int level;
+ enum vmpressure_modes mode = VMPRESSURE_NO_PASSTHROUGH;
+ enum vmpressure_levels level = -1;
+ char *spec, *spec_orig;
+ char *token;
+ int ret = 0;
+
+ spec_orig = spec = kzalloc(MAX_VMPRESSURE_ARGS_LEN + 1, GFP_KERNEL);
+ if (!spec) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ strncpy(spec, args, MAX_VMPRESSURE_ARGS_LEN);
- for (level = 0; level < VMPRESSURE_NUM_LEVELS; level++) {
- if (!strcmp(vmpressure_str_levels[level], args))
- break;
+ /* Find required level */
+ token = strsep(&spec, ",");
+ level = str_to_level(token);
+ if (level == -1) {
+ ret = -EINVAL;
+ goto out;
}
- if (level >= VMPRESSURE_NUM_LEVELS)
- return -EINVAL;
+ /* Find optional mode */
+ token = strsep(&spec, ",");
+ if (token) {
+ mode = str_to_mode(token);
+ if (mode == -1) {
+ ret = -EINVAL;
+ goto out;
+ }
+ }
ev = kzalloc(sizeof(*ev), GFP_KERNEL);
- if (!ev)
- return -ENOMEM;
+ if (!ev) {
+ ret = -ENOMEM;
+ goto out;
+ }
ev->efd = eventfd;
ev->level = level;
+ ev->mode = mode;
mutex_lock(&vmpr->events_lock);
list_add(&ev->node, &vmpr->events);
mutex_unlock(&vmpr->events_lock);
-
- return 0;
+out:
+ kfree(spec_orig);
+ return ret;
}
/**