ocfs2: Local alloc window size changeable via mount option

Local alloc is a performance optimization in ocfs2 in which a node
takes a window of bits from the global bitmap and then uses that for
all small local allocations. This window size is fixed to 8MB currently.
This patch allows users to specify the window size in MB including
disabling it by passing in 0. If the number specified is too large,
the fs will use the default value of 8MB.

mount -o localalloc=X /dev/sdX /mntpoint

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

diff --git a/Documentation/filesystems/ocfs2.txt b/Documentation/filesystems/ocfs2.txt
index b63bd2d7fcd3017bc8d63206da7e7978d143bce9..071fad137eb553b5ba2dd158c615ce185cccd294 100644 (file)
--- a/Documentation/filesystems/ocfs2.txt
+++ b/Documentation/filesystems/ocfs2.txt
@@ -72,3 +72,6 @@ commit=nrsec  (*)     Ocfs2 can be told to sync all its data and metadata
                        it at the default (5 seconds).
                        Setting it to very large values will improve
                        performance.
+localalloc=8(*)                Allows custom localalloc size in MB. If the value is too
+                       large, the fs will silently revert it to the default.
+                       Localalloc is not enabled for local mounts.

diff --git a/fs/ocfs2/localalloc.c b/fs/ocfs2/localalloc.c
index 0de0792fce7fdb80775c0683ebd13145fb964807..add1ffdc5c6c75bb2accdb65972466f2651e80c8 100644 (file)
--- a/fs/ocfs2/localalloc.c
+++ b/fs/ocfs2/localalloc.c
@@ -75,18 +75,12 @@ static int ocfs2_local_alloc_new_window(struct ocfs2_super *osb,
 static int ocfs2_local_alloc_slide_window(struct ocfs2_super *osb,
                                          struct inode *local_alloc_inode);
 
-/*
- * Determine how large our local alloc window should be, in bits.
- *
- * These values (and the behavior in ocfs2_alloc_should_use_local) have
- * been chosen so that most allocations, including new block groups go
- * through local alloc.
- */
 static inline int ocfs2_local_alloc_window_bits(struct ocfs2_super *osb)
 {
-       BUG_ON(osb->s_clustersize_bits < 12);
+       BUG_ON(osb->s_clustersize_bits > 20);
 
-       return 2048 >> (osb->s_clustersize_bits - 12);
+       /* Size local alloc windows by the megabyte */
+       return osb->local_alloc_size << (20 - osb->s_clustersize_bits);
 }
 
 /*
@@ -96,18 +90,23 @@ static inline int ocfs2_local_alloc_window_bits(struct ocfs2_super *osb)
 int ocfs2_alloc_should_use_local(struct ocfs2_super *osb, u64 bits)
 {
        int la_bits = ocfs2_local_alloc_window_bits(osb);
+       int ret = 0;
 
        if (osb->local_alloc_state != OCFS2_LA_ENABLED)
-               return 0;
+               goto bail;
 
        /* la_bits should be at least twice the size (in clusters) of
         * a new block group. We want to be sure block group
         * allocations go through the local alloc, so allow an
         * allocation to take up to half the bitmap. */
        if (bits > (la_bits / 2))
-               return 0;
+               goto bail;
 
-       return 1;
+       ret = 1;
+bail:
+       mlog(0, "state=%d, bits=%llu, la_bits=%d, ret=%d\n",
+            osb->local_alloc_state, (unsigned long long)bits, la_bits, ret);
+       return ret;
 }
 
 int ocfs2_load_local_alloc(struct ocfs2_super *osb)
@@ -121,6 +120,19 @@ int ocfs2_load_local_alloc(struct ocfs2_super *osb)
 
        mlog_entry_void();
 
+       if (ocfs2_mount_local(osb))
+               goto bail;
+
+       if (osb->local_alloc_size == 0)
+               goto bail;
+
+       if (ocfs2_local_alloc_window_bits(osb) >= osb->bitmap_cpg) {
+               mlog(ML_NOTICE, "Requested local alloc window %d is larger "
+                    "than max possible %u. Using defaults.\n",
+                    ocfs2_local_alloc_window_bits(osb), (osb->bitmap_cpg - 1));
+               osb->local_alloc_size = OCFS2_DEFAULT_LOCAL_ALLOC_SIZE;
+       }
+
        /* read the alloc off disk */
        inode = ocfs2_get_system_file_inode(osb, LOCAL_ALLOC_SYSTEM_INODE,
                                            osb->slot_num);
@@ -181,6 +193,9 @@ bail:
        if (inode)
                iput(inode);
 
+       mlog(0, "Local alloc window bits = %d\n",
+            ocfs2_local_alloc_window_bits(osb));
+
        mlog_exit(status);
        return status;
 }
@@ -521,6 +536,9 @@ bail:
                iput(local_alloc_inode);
        }
 
+       mlog(0, "bits=%d, slot=%d, ret=%d\n", bits_wanted, osb->slot_num,
+            status);
+
        mlog_exit(status);
        return status;
 }

diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 82802f5672a1859a1932df82b42eba42795a2eee..d12bd7036da7ad52ada64b73d31727ae34ffa2ee 100644 (file)
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -231,6 +231,7 @@ struct ocfs2_super
        struct ocfs2_journal *journal;
        unsigned long osb_commit_interval;
 
+       int local_alloc_size;
        enum ocfs2_local_alloc_state local_alloc_state;
        struct buffer_head *local_alloc_bh;
        u64 la_last_gd;

diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index 425551737f1f0566e4b549d4ee4019ab95d88223..3633edd3982f731a1c1c67bf1cdab945eea0689e 100644 (file)
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -270,6 +270,14 @@ struct ocfs2_new_group_input {
 /* Journal limits (in bytes) */
 #define OCFS2_MIN_JOURNAL_SIZE         (4 * 1024 * 1024)
 
+/*
+ * Default local alloc size (in megabytes)
+ *
+ * The value chosen should be such that most allocations, including new
+ * block groups, use local alloc.
+ */
+#define OCFS2_DEFAULT_LOCAL_ALLOC_SIZE 8
+
 struct ocfs2_system_inode_info {
        char    *si_name;
        int     si_iflags;

diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index 4391744e80f8aea26e36e621561d05cddb69512f..7e397e2c25dd219fd55e3f16c363488fb57223e6 100644 (file)
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -1516,8 +1516,9 @@ int __ocfs2_claim_clusters(struct ocfs2_super *osb,
                if (min_clusters > (osb->bitmap_cpg - 1)) {
                        /* The only paths asking for contiguousness
                         * should know about this already. */
-                       mlog(ML_ERROR, "minimum allocation requested exceeds "
-                                      "group bitmap size!");
+                       mlog(ML_ERROR, "minimum allocation requested %u exceeds "
+                            "group bitmap size %u!\n", min_clusters,
+                            osb->bitmap_cpg);
                        status = -ENOSPC;
                        goto bail;
                }

diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 8044ed97d36263161ad0c81ebb36225df56f08d4..1104f14c318366f4da5fc495c682f7798201a53a 100644 (file)
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -87,6 +87,7 @@ struct mount_options
        unsigned long   mount_opt;
        unsigned int    atime_quantum;
        signed short    slot;
+       unsigned int    localalloc_opt;
 };
 
 static int ocfs2_parse_options(struct super_block *sb, char *options,
@@ -151,6 +152,7 @@ enum {
        Opt_atime_quantum,
        Opt_slot,
        Opt_commit,
+       Opt_localalloc,
        Opt_err,
 };
 
@@ -167,6 +169,7 @@ static match_table_t tokens = {
        {Opt_atime_quantum, "atime_quantum=%u"},
        {Opt_slot, "preferred_slot=%u"},
        {Opt_commit, "commit=%u"},
+       {Opt_localalloc, "localalloc=%d"},
        {Opt_err, NULL}
 };
 
@@ -602,6 +605,7 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
        osb->s_atime_quantum = parsed_options.atime_quantum;
        osb->preferred_slot = parsed_options.slot;
        osb->osb_commit_interval = parsed_options.commit_interval;
+       osb->local_alloc_size = parsed_options.localalloc_opt;
 
        sb->s_magic = OCFS2_SUPER_MAGIC;
 
@@ -756,6 +760,7 @@ static int ocfs2_parse_options(struct super_block *sb,
        mopt->mount_opt = 0;
        mopt->atime_quantum = OCFS2_DEFAULT_ATIME_QUANTUM;
        mopt->slot = OCFS2_INVALID_SLOT;
+       mopt->localalloc_opt = OCFS2_DEFAULT_LOCAL_ALLOC_SIZE;
 
        if (!options) {
                status = 1;
@@ -834,6 +839,15 @@ static int ocfs2_parse_options(struct super_block *sb,
                                option = JBD_DEFAULT_MAX_COMMIT_AGE;
                        mopt->commit_interval = HZ * option;
                        break;
+               case Opt_localalloc:
+                       option = 0;
+                       if (match_int(&args[0], &option)) {
+                               status = 0;
+                               goto bail;
+                       }
+                       if (option >= 0 && (option <= ocfs2_local_alloc_size(sb) * 8))
+                               mopt->localalloc_opt = option;
+                       break;
                default:
                        mlog(ML_ERROR,
                             "Unrecognized mount option \"%s\" "
@@ -886,6 +900,9 @@ static int ocfs2_show_options(struct seq_file *s, struct vfsmount *mnt)
                seq_printf(s, ",commit=%u",
                           (unsigned) (osb->osb_commit_interval / HZ));
 
+       if (osb->local_alloc_size != OCFS2_DEFAULT_LOCAL_ALLOC_SIZE)
+               seq_printf(s, ",localalloc=%d", osb->local_alloc_size);
+
        return 0;
 }