diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/vmpressure.c | 122 |
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; } /** |