Staging: android: add lowmemorykiller driver

From: San Mehat <san@android.com>
Cc: Brian Swetland <swetland@google.com>
Cc: Robert Love <rlove@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/android/Kconfig b/drivers/staging/android/Kconfig
index 502c283eedcc030ec5cf6c5ad6d7d486c57ac6a4..934f6f2019b33b269cdbe4b0ce69999bf858aaa8 100644 (file)
--- a/drivers/staging/android/Kconfig
+++ b/drivers/staging/android/Kconfig
@@ -77,4 +77,10 @@ config ANDROID_TIMED_GPIO
        depends on GENERIC_GPIO
        default n
 
+config ANDROID_LOW_MEMORY_KILLER
+       bool "Android Low Memory Killer"
+       default N
+       ---help---
+         Register processes to be killed when memory is low
+
 endmenu

diff --git a/drivers/staging/android/Makefile b/drivers/staging/android/Makefile
index 7ea6fbe92f4b57274eec921f1725e218d63e208d..95209d6273a154033cc69b97675a799c4a0209b6 100644 (file)
--- a/drivers/staging/android/Makefile
+++ b/drivers/staging/android/Makefile
@@ -2,3 +2,4 @@ obj-$(CONFIG_ANDROID_BINDER_IPC)        += binder.o
 obj-$(CONFIG_ANDROID_LOGGER)           += logger.o
 obj-$(CONFIG_ANDROID_RAM_CONSOLE)      += ram_console.o
 obj-$(CONFIG_ANDROID_TIMED_GPIO)       += timed_gpio.o
+obj-$(CONFIG_ANDROID_LOW_MEMORY_KILLER)        += lowmemorykiller.o

diff --git a/drivers/staging/android/lowmemorykiller.c b/drivers/staging/android/lowmemorykiller.c
new file mode 100644 (file)
index 0000000..3715d56
--- /dev/null
+++ b/drivers/staging/android/lowmemorykiller.c
@@ -0,0 +1,119 @@
+/* drivers/misc/lowmemorykiller.c
+ *
+ * Copyright (C) 2007-2008 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/oom.h>
+#include <linux/sched.h>
+
+static int lowmem_shrink(int nr_to_scan, gfp_t gfp_mask);
+
+static struct shrinker lowmem_shrinker = {
+       .shrink = lowmem_shrink,
+       .seeks = DEFAULT_SEEKS * 16
+};
+static uint32_t lowmem_debug_level = 2;
+static int lowmem_adj[6] = {
+       0,
+       1,
+       6,
+       12,
+};
+static int lowmem_adj_size = 4;
+static size_t lowmem_minfree[6] = {
+       3*512, // 6MB
+       2*1024, // 8MB
+       4*1024, // 16MB
+       16*1024, // 64MB
+};
+static int lowmem_minfree_size = 4;
+
+#define lowmem_print(level, x...) do { if(lowmem_debug_level >= (level)) printk(x); } while(0)
+
+module_param_named(cost, lowmem_shrinker.seeks, int, S_IRUGO | S_IWUSR);
+module_param_array_named(adj, lowmem_adj, int, &lowmem_adj_size, S_IRUGO | S_IWUSR);
+module_param_array_named(minfree, lowmem_minfree, uint, &lowmem_minfree_size, S_IRUGO | S_IWUSR);
+module_param_named(debug_level, lowmem_debug_level, uint, S_IRUGO | S_IWUSR);
+
+static int lowmem_shrink(int nr_to_scan, gfp_t gfp_mask)
+{
+       struct task_struct *p;
+       struct task_struct *selected = NULL;
+       int rem = 0;
+       int tasksize;
+       int i;
+       int min_adj = OOM_ADJUST_MAX + 1;
+       int selected_tasksize = 0;
+       int array_size = ARRAY_SIZE(lowmem_adj);
+       int other_free = global_page_state(NR_FREE_PAGES) + global_page_state(NR_FILE_PAGES);
+       if(lowmem_adj_size < array_size)
+               array_size = lowmem_adj_size;
+       if(lowmem_minfree_size < array_size)
+               array_size = lowmem_minfree_size;
+       for(i = 0; i < array_size; i++) {
+               if(other_free < lowmem_minfree[i]) {
+                       min_adj = lowmem_adj[i];
+                       break;
+               }
+       }
+       if(nr_to_scan > 0)
+               lowmem_print(3, "lowmem_shrink %d, %x, ofree %d, ma %d\n", nr_to_scan, gfp_mask, other_free, min_adj);
+       read_lock(&tasklist_lock);
+       for_each_process(p) {
+               if(p->oomkilladj >= 0 && p->mm) {
+                       tasksize = get_mm_rss(p->mm);
+                       if(nr_to_scan > 0 && tasksize > 0 && p->oomkilladj >= min_adj) {
+                               if(selected == NULL ||
+                                  p->oomkilladj > selected->oomkilladj ||
+                                  (p->oomkilladj == selected->oomkilladj &&
+                                   tasksize > selected_tasksize)) {
+                                       selected = p;
+                                       selected_tasksize = tasksize;
+                                       lowmem_print(2, "select %d (%s), adj %d, size %d, to kill\n",
+                                                    p->pid, p->comm, p->oomkilladj, tasksize);
+                               }
+                       }
+                       rem += tasksize;
+               }
+       }
+       if(selected != NULL) {
+               lowmem_print(1, "send sigkill to %d (%s), adj %d, size %d\n",
+                            selected->pid, selected->comm,
+                            selected->oomkilladj, selected_tasksize);
+               force_sig(SIGKILL, selected);
+               rem -= selected_tasksize;
+       }
+       lowmem_print(4, "lowmem_shrink %d, %x, return %d\n", nr_to_scan, gfp_mask, rem);
+       read_unlock(&tasklist_lock);
+       return rem;
+}
+
+static int __init lowmem_init(void)
+{
+       register_shrinker(&lowmem_shrinker);
+       return 0;
+}
+
+static void __exit lowmem_exit(void)
+{
+       unregister_shrinker(&lowmem_shrinker);
+}
+
+module_init(lowmem_init);
+module_exit(lowmem_exit);
+
+MODULE_LICENSE("GPL");
+