Re: [patch] Convert sockets_in_use to use per_cpu areas
From: Ravikiran G Thirumalai <hidden>
Date: 2002-12-24 06:43:47
On Mon, Dec 23, 2002 at 12:16:32PM -0800, David S. Miller wrote:
...
-static union {
- int counter;
- char __pad[SMP_CACHE_BYTES];
-} sockets_in_use[NR_CPUS] __cacheline_aligned = {{0}};
+static DEFINE_PER_CPU(int, sockets_in_use);
You have to provide an explicit initializer for DEFINE_PER_CPU
declarations or you break some platforms with older GCC's which
otherwise won't put it into the proper section.Ok, here's the modified patch... Thanks, Kiran diff -ruN -X dontdiff linux-2.5.52/net/socket.c sockets_in_use-2.5.52/net/socket.c
--- linux-2.5.52/net/socket.c Mon Dec 16 07:37:53 2002
+++ sockets_in_use-2.5.52/net/socket.c Tue Dec 24 05:11:36 2002@@ -189,10 +189,7 @@ * Statistics counters of the socket lists */ -static union { - int counter; - char __pad[SMP_CACHE_BYTES]; -} sockets_in_use[NR_CPUS] __cacheline_aligned = {{0}}; +static DEFINE_PER_CPU(int, sockets_in_use) = 0; /* * Support routines. Move socket addresses back and forth across the kernel/user
@@ -475,7 +472,8 @@ inode->i_uid = current->fsuid; inode->i_gid = current->fsgid; - sockets_in_use[smp_processor_id()].counter++; + get_cpu_var(sockets_in_use)++; + put_cpu_var(sockets_in_use); return sock; }
@@ -511,7 +509,8 @@ if (sock->fasync_list) printk(KERN_ERR "sock_release: fasync list not empty!\n"); - sockets_in_use[smp_processor_id()].counter--; + get_cpu_var(sockets_in_use)--; + put_cpu_var(sockets_in_use); if (!sock->file) { iput(SOCK_INODE(sock)); return;
@@ -1851,7 +1850,7 @@ int counter = 0; for (cpu = 0; cpu < NR_CPUS; cpu++) - counter += sockets_in_use[cpu].counter; + counter += per_cpu(sockets_in_use, cpu); /* It can be negative, by the way. 8) */ if (counter < 0)