ceph: writeback congestion control

[net-next-2.6.git] / fs / ceph / super.c

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 6d02a166f8ffe6d61068ced19f030063311d9408..b9cb8cebcdc1b19bace63f327182a211f32f43a5 100644 (file)
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -150,6 +150,35 @@ static void ceph_inode_init_once(void *foo)
        inode_init_once(&ci->vfs_inode);
 }
 
+static int default_congestion_kb(void)
+{
+       int congestion_kb;
+
+       /*
+        * Copied from NFS
+        *
+        * congestion size, scale with available memory.
+        *
+        *  64MB:    8192k
+        * 128MB:   11585k
+        * 256MB:   16384k
+        * 512MB:   23170k
+        *   1GB:   32768k
+        *   2GB:   46340k
+        *   4GB:   65536k
+        *   8GB:   92681k
+        *  16GB:  131072k
+        *
+        * This allows larger machines to have larger/more transfers.
+        * Limit the default to 256M
+        */
+       congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
+       if (congestion_kb > 256*1024)
+               congestion_kb = 256*1024;
+
+       return congestion_kb;
+}
+
 static int __init init_caches(void)
 {
        ceph_inode_cachep = kmem_cache_create("ceph_inode_info",
@@ -267,6 +296,7 @@ enum {
        Opt_caps_wanted_delay_min,
        Opt_caps_wanted_delay_max,
        Opt_readdir_max_entries,
+       Opt_congestion_kb,
        Opt_last_int,
        /* int args above */
        Opt_snapdirname,
@@ -295,6 +325,7 @@ static match_table_t arg_tokens = {
        {Opt_caps_wanted_delay_min, "caps_wanted_delay_min=%d"},
        {Opt_caps_wanted_delay_max, "caps_wanted_delay_max=%d"},
        {Opt_readdir_max_entries, "readdir_max_entries=%d"},
+       {Opt_congestion_kb, "write_congestion_kb=%d"},
        /* int args above */
        {Opt_snapdirname, "snapdirname=%s"},
        {Opt_name, "name=%s"},
@@ -342,6 +373,7 @@ static struct ceph_mount_args *parse_mount_args(int flags, char *options,
        args->snapdir_name = kstrdup(CEPH_SNAPDIRNAME_DEFAULT, GFP_KERNEL);
        args->cap_release_safety = CEPH_CAPS_PER_RELEASE * 4;
        args->max_readdir = 1024;
+       args->congestion_kb = default_congestion_kb();
 
        /* ip1[:port1][,ip2[:port2]...]:/subdir/in/fs */
        err = -EINVAL;
@@ -445,6 +477,9 @@ static struct ceph_mount_args *parse_mount_args(int flags, char *options,
                case Opt_readdir_max_entries:
                        args->max_readdir = intval;
                        break;
+               case Opt_congestion_kb:
+                       args->congestion_kb = intval;
+                       break;
 
                case Opt_noshare:
                        args->flags |= CEPH_OPT_NOSHARE;
@@ -516,6 +551,7 @@ static struct ceph_client *ceph_create_client(struct ceph_mount_args *args)
        client->msgr = NULL;
 
        client->mount_err = 0;
+       atomic_long_set(&client->writeback_count, 0);
 
        err = bdi_init(&client->backing_dev_info);
        if (err < 0)