Remove constructor from buffer_head Performance tests show a slight improvements in netperf (not a strong case for a performance improvement but removing the constructor has definitely no negative impact so why keep this around?). TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to localhost (127.0.0.1) port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec Before: 87380 16384 16384 10.01 6026.04 87380 16384 16384 10.01 5992.17 87380 16384 16384 10.01 6071.23 After: 87380 16384 16384 10.01 6090.20 87380 16384 16384 10.01 6078.3 87380 16384 16384 10.00 6013.52 Signed-off-by: Christoph Lameter --- fs/buffer.c | 22 ++++------------------ 1 file changed, 4 insertions(+), 18 deletions(-) Index: slub/fs/buffer.c =================================================================== --- slub.orig/fs/buffer.c 2007-05-03 19:17:09.000000000 -0700 +++ slub/fs/buffer.c 2007-05-03 19:57:30.000000000 -0700 @@ -2907,9 +2907,10 @@ static void recalc_bh_state(void) struct buffer_head *alloc_buffer_head(gfp_t gfp_flags) { - struct buffer_head *ret = kmem_cache_alloc(bh_cachep, + struct buffer_head *ret = kmem_cache_zalloc(bh_cachep, set_migrateflags(gfp_flags, __GFP_RECLAIMABLE)); if (ret) { + INIT_LIST_HEAD(&ret->b_assoc_buffers); get_cpu_var(bh_accounting).nr++; recalc_bh_state(); put_cpu_var(bh_accounting); @@ -2928,17 +2929,6 @@ void free_buffer_head(struct buffer_head } EXPORT_SYMBOL(free_buffer_head); -static void -init_buffer_head(void *data, struct kmem_cache *cachep, unsigned long flags) -{ - if (flags & SLAB_CTOR_CONSTRUCTOR) { - struct buffer_head * bh = (struct buffer_head *)data; - - memset(bh, 0, sizeof(*bh)); - INIT_LIST_HEAD(&bh->b_assoc_buffers); - } -} - static void buffer_exit_cpu(int cpu) { int i; @@ -2965,12 +2955,8 @@ void __init buffer_init(void) { int nrpages; - bh_cachep = kmem_cache_create("buffer_head", - sizeof(struct buffer_head), 0, - (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| - SLAB_MEM_SPREAD), - init_buffer_head, - NULL); + bh_cachep = KMEM_CACHE(buffer_head, + SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD); /* * Limit the bh occupancy to 10% of ZONE_NORMAL