[PATCH] dcache: Deduplicate code that sets up dentry_hashtable
From: Eric Biggers
Date: Wed Sep 23 2015 - 00:58:09 EST
Make both dcache_init_early() and dcache_init() call a new helper
function, dcache_alloc_hashtable(). Also address a small inefficiency by
moving the table length calculation outside of the loop condition. gcc
apparently doesn't do that because it assumes that the memory pointed to
by 'dentry_hashtable' might alias 'd_hash_shift'.
Signed-off-by: Eric Biggers <ebiggers3@xxxxxxxxx>
---
fs/dcache.c | 48 +++++++++++++++++++-----------------------------
1 file changed, 19 insertions(+), 29 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index 5c33aeb..7cfe848 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -3380,35 +3380,39 @@ static int __init set_dhash_entries(char *str)
}
__setup("dhash_entries=", set_dhash_entries);
-static void __init dcache_init_early(void)
+static void __init dcache_alloc_hashtable(int flags)
{
- unsigned int loop;
-
- /* If hashes are distributed across NUMA nodes, defer
- * hash allocation until vmalloc space is available.
- */
- if (hashdist)
- return;
+ unsigned int num_entries;
+ unsigned int i;
dentry_hashtable =
alloc_large_system_hash("Dentry cache",
sizeof(struct hlist_bl_head),
dhash_entries,
13,
- HASH_EARLY,
+ flags,
&d_hash_shift,
&d_hash_mask,
0,
0);
- for (loop = 0; loop < (1U << d_hash_shift); loop++)
- INIT_HLIST_BL_HEAD(dentry_hashtable + loop);
+ num_entries = 1U << d_hash_shift;
+
+ for (i = 0; i < num_entries; i++)
+ INIT_HLIST_BL_HEAD(&dentry_hashtable[i]);
}
-static void __init dcache_init(void)
+static void __init dcache_init_early(void)
{
- unsigned int loop;
+ /* If hashes are distributed across NUMA nodes, defer
+ * hash allocation until vmalloc space is available.
+ */
+ if (!hashdist)
+ dcache_alloc_hashtable(HASH_EARLY);
+}
+static void __init dcache_init(void)
+{
/*
* A constructor could be added for stable state like the lists,
* but it is probably not worth it because of the cache nature
@@ -3418,22 +3422,8 @@ static void __init dcache_init(void)
SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD);
/* Hash may have been set up in dcache_init_early */
- if (!hashdist)
- return;
-
- dentry_hashtable =
- alloc_large_system_hash("Dentry cache",
- sizeof(struct hlist_bl_head),
- dhash_entries,
- 13,
- 0,
- &d_hash_shift,
- &d_hash_mask,
- 0,
- 0);
-
- for (loop = 0; loop < (1U << d_hash_shift); loop++)
- INIT_HLIST_BL_HEAD(dentry_hashtable + loop);
+ if (hashdist)
+ dcache_alloc_hashtable(0);
}
/* SLAB cache for __getname() consumers */
--
2.4.3
--
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