mm: update callers to use HASH_ZERO flag

Update dcache, inode, pid, mountpoint, and mount hash tables to use
HASH_ZERO, and remove initialization after allocations.  In case of
places where HASH_EARLY was used such as in __pv_init_lock_hash the
zeroed hash table was already assumed, because memblock zeroes the
memory.

CPU: SPARC M6, Memory: 7T
Before fix:
  Dentry cache hash table entries: 1073741824
  Inode-cache hash table entries: 536870912
  Mount-cache hash table entries: 16777216
  Mountpoint-cache hash table entries: 16777216
  ftrace: allocating 20414 entries in 40 pages
  Total time: 11.798s

After fix:
  Dentry cache hash table entries: 1073741824
  Inode-cache hash table entries: 536870912
  Mount-cache hash table entries: 16777216
  Mountpoint-cache hash table entries: 16777216
  ftrace: allocating 20414 entries in 40 pages
  Total time: 3.198s

CPU: Intel Xeon E5-2630, Memory: 2.2T:
Before fix:
  Dentry cache hash table entries: 536870912
  Inode-cache hash table entries: 268435456
  Mount-cache hash table entries: 8388608
  Mountpoint-cache hash table entries: 8388608
  CPU: Physical Processor ID: 0
  Total time: 3.245s

After fix:
  Dentry cache hash table entries: 536870912
  Inode-cache hash table entries: 268435456
  Mount-cache hash table entries: 8388608
  Mountpoint-cache hash table entries: 8388608
  CPU: Physical Processor ID: 0
  Total time: 3.244s

Link: http://lkml.kernel.org/r/1488432825-92126-4-git-send-email-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Cc: David Miller <davem@davemloft.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 12 deletions

diff --git a/fs/inode.c b/fs/inode.c
index ab3b9a795c0b..5cbc8e6e9390 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1915,8 +1915,6 @@ __setup("ihash_entries=", set_ihash_entries);
  */
 void __init inode_init_early(void)
 {
-        unsigned int loop;
-
         /* If hashes are distributed across NUMA nodes, defer
          * hash allocation until vmalloc space is available.
          */
@@ -1928,20 +1926,15 @@ void __init inode_init_early(void)
                                         sizeof(struct hlist_head),
                                         ihash_entries,
                                         14,
-                                        HASH_EARLY,
+                                        HASH_EARLY | HASH_ZERO,
                                         &i_hash_shift,
                                         &i_hash_mask,
                                         0,
                                         0);
-
-        for (loop = 0; loop < (1U << i_hash_shift); loop++)
-                INIT_HLIST_HEAD(&inode_hashtable[loop]);
 }
 
 void __init inode_init(void)
 {
-        unsigned int loop;
-
         /* inode slab cache */
         inode_cachep = kmem_cache_create("inode_cache",
                                          sizeof(struct inode),
@@ -1959,14 +1952,11 @@ void __init inode_init(void)
                                         sizeof(struct hlist_head),
                                         ihash_entries,
                                         14,
-                                        0,
+                                        HASH_ZERO,
                                         &i_hash_shift,
                                         &i_hash_mask,
                                         0,
                                         0);
-
-        for (loop = 0; loop < (1U << i_hash_shift); loop++)
-                INIT_HLIST_HEAD(&inode_hashtable[loop]);
 }
 
 void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)