Revision e8a03feb54ca7f1768bbdc2b491f9ef654e6d01d authored by Rik van Riel on 14 April 2010, 21:59:28 UTC, committed by Linus Torvalds on 19 April 2010, 23:28:20 UTC
The recent anon_vma fixes cause many anonymous pages to end up in the parent process anon_vma, even when the page is exclusively owned by the current process. Adding exclusively owned anonymous pages to the top anon_vma reduces rmap scanning overhead, especially in workloads with forking servers. This patch adds a parameter to __page_set_anon_rmap that can be used to indicate whether or not the added page is exclusively owned by the current process. Pages added through page_add_new_anon_rmap are exclusively owned by the current process, and can be added to the top anon_vma. Pages added through page_add_anon_rmap can be either shared or exclusively owned, so we do the conservative thing and add it to the oldest anon_vma. A next step would be to add the exclusive parameter to page_add_anon_rmap, to be used from functions where we do know for sure whether a page is exclusively owned. Signed-off-by: Rik van Riel <riel@redhat.com> Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> Lightly-tested-by: Borislav Petkov <bp@alien8.de> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> [ Edited to look nicer - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 9b030e2
find_last_bit.c
/* find_last_bit.c: fallback find next bit implementation
*
* Copyright (C) 2008 IBM Corporation
* Written by Rusty Russell <rusty@rustcorp.com.au>
* (Inspired by David Howell's find_next_bit implementation)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/bitops.h>
#include <linux/module.h>
#include <asm/types.h>
#include <asm/byteorder.h>
unsigned long find_last_bit(const unsigned long *addr, unsigned long size)
{
unsigned long words;
unsigned long tmp;
/* Start at final word. */
words = size / BITS_PER_LONG;
/* Partial final word? */
if (size & (BITS_PER_LONG-1)) {
tmp = (addr[words] & (~0UL >> (BITS_PER_LONG
- (size & (BITS_PER_LONG-1)))));
if (tmp)
goto found;
}
while (words) {
tmp = addr[--words];
if (tmp) {
found:
return words * BITS_PER_LONG + __fls(tmp);
}
}
/* Not found */
return size;
}
EXPORT_SYMBOL(find_last_bit);
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