1. 30 Dec, 2009 1 commit
    • Jan Beulich's avatar
      x86: Lift restriction on the location of FIX_BTMAP_* · 499a5f1e
      Jan Beulich authored
      The early ioremap fixmap entries cover half (or for 32-bit
      non-PAE, a quarter) of a page table, yet they got
      uncondtitionally aligned so far to a 256-entry boundary. This is
      not necessary if the range of page table entries anyway falls
      into a single page table.
      
      This buys back, for (theoretically) 50% of all configurations
      (25% of all non-PAE ones), at least some of the lowmem
      necessarily lost with commit e621bd18.
      Signed-off-by: default avatarJan Beulich <jbeulich@novell.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      LKML-Reference: <4B2BB66F0200007800026AD6@vpn.id2.novell.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      499a5f1e
  2. 28 Dec, 2009 1 commit
    • Akinobu Mita's avatar
      x86, core: Optimize hweight32() · 39d997b5
      Akinobu Mita authored
      Optimize hweight32 by using the same technique in hweight64.
      
      The proof of this technique can be found in the commit log for
      f9b41929 ("bitops: hweight()
      speedup").
      
      The userspace benchmark on x86_32 showed 20% speedup with
      bitmap_weight() which uses hweight32 to count bits for each
      unsigned long on 32bit architectures.
      
       int main(void)
       {
      	#define SZ (1024 * 1024 * 512)
      
      	static DECLARE_BITMAP(bitmap, SZ) = {
      	        [0 ... 100] = 1,
      	};
      
      	return bitmap_weight(bitmap, SZ);
       }
      Signed-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      LKML-Reference: <1258603932-4590-1-git-send-email-akinobu.mita@gmail.com>
      [ only x86 sets ARCH_HAS_FAST_MULTIPLIER so we do this via the x86 tree]
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      39d997b5
  3. 24 Dec, 2009 38 commits