1. 15 Jun, 2011 26 commits
  2. 13 Jun, 2011 13 commits
  3. 11 Jun, 2011 1 commit
    • Eric Dumazet's avatar
      snmp: reduce percpu needs by 50% · 8f0ea0fe
      Eric Dumazet authored
      SNMP mibs use two percpu arrays, one used in BH context, another in USER
      context. With increasing number of cpus in machines, and fact that ipv6
      uses per network device ipstats_mib, this is consuming a lot of memory
      if many network devices are registered.
      
      commit be281e55 (ipv6: reduce per device ICMP mib sizes) shrinked
      percpu needs for ipv6, but we can reduce memory use a bit more.
      
      With recent percpu infrastructure (irqsafe_cpu_inc() ...), we no longer
      need this BH/USER separation since we can update counters in a single
      x86 instruction, regardless of the BH/USER context.
      
      Other arches than x86 might need to disable irq in their
      irqsafe_cpu_inc() implementation : If this happens to be a problem, we
      can make SNMP_ARRAY_SZ arch dependent, but a previous poll
      ( https://lkml.org/lkml/2011/3/17/174 ) to arch maintainers did not
      raise strong opposition.
      
      Only on 32bit arches, we need to disable BH for 64bit counters updates
      done from USER context (currently used for IP MIB)
      
      This also reduces vmlinux size :
      
      1) x86_64 build
      $ size vmlinux.before vmlinux.after
         text	   data	    bss	    dec	    hex	filename
      7853650	1293772	1896448	11043870	 a8841e	vmlinux.before
      7850578	1293772	1896448	11040798	 a8781e	vmlinux.after
      
      2) i386  build
      $ size vmlinux.before vmlinux.afterpatch
         text	   data	    bss	    dec	    hex	filename
      6039335	 635076	3670016	10344427	 9dd7eb	vmlinux.before
      6037342	 635076	3670016	10342434	 9dd022	vmlinux.afterpatch
      Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      CC: Andi Kleen <andi@firstfloor.org>
      CC: Ingo Molnar <mingo@elte.hu>
      CC: Tejun Heo <tj@kernel.org>
      CC: Christoph Lameter <cl@linux-foundation.org>
      CC: Benjamin Herrenschmidt <benh@kernel.crashing.org
      CC: linux-arch@vger.kernel.org
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      8f0ea0fe