https://github.com/torvalds/linux
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
Tip revision: e8a03feb54ca7f1768bbdc2b491f9ef654e6d01d authored by Rik van Riel on 14 April 2010, 21:59:28 UTC
rmap: add exclusively owned pages to the newest anon_vma
rmap: add exclusively owned pages to the newest anon_vma
Tip revision: e8a03fe
binfmt_em86.c
/*
* linux/fs/binfmt_em86.c
*
* Based on linux/fs/binfmt_script.c
* Copyright (C) 1996 Martin von Löwis
* original #!-checking implemented by tytso.
*
* em86 changes Copyright (C) 1997 Jim Paradis
*/
#include <linux/module.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/binfmts.h>
#include <linux/elf.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/errno.h>
#define EM86_INTERP "/usr/bin/em86"
#define EM86_I_NAME "em86"
static int load_em86(struct linux_binprm *bprm,struct pt_regs *regs)
{
char *interp, *i_name, *i_arg;
struct file * file;
int retval;
struct elfhdr elf_ex;
/* Make sure this is a Linux/Intel ELF executable... */
elf_ex = *((struct elfhdr *)bprm->buf);
if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
return -ENOEXEC;
/* First of all, some simple consistency checks */
if ((elf_ex.e_type != ET_EXEC && elf_ex.e_type != ET_DYN) ||
(!((elf_ex.e_machine == EM_386) || (elf_ex.e_machine == EM_486))) ||
(!bprm->file->f_op || !bprm->file->f_op->mmap)) {
return -ENOEXEC;
}
bprm->recursion_depth++; /* Well, the bang-shell is implicit... */
allow_write_access(bprm->file);
fput(bprm->file);
bprm->file = NULL;
/* Unlike in the script case, we don't have to do any hairy
* parsing to find our interpreter... it's hardcoded!
*/
interp = EM86_INTERP;
i_name = EM86_I_NAME;
i_arg = NULL; /* We reserve the right to add an arg later */
/*
* Splice in (1) the interpreter's name for argv[0]
* (2) (optional) argument to interpreter
* (3) filename of emulated file (replace argv[0])
*
* This is done in reverse order, because of how the
* user environment and arguments are stored.
*/
remove_arg_zero(bprm);
retval = copy_strings_kernel(1, &bprm->filename, bprm);
if (retval < 0) return retval;
bprm->argc++;
if (i_arg) {
retval = copy_strings_kernel(1, &i_arg, bprm);
if (retval < 0) return retval;
bprm->argc++;
}
retval = copy_strings_kernel(1, &i_name, bprm);
if (retval < 0) return retval;
bprm->argc++;
/*
* OK, now restart the process with the interpreter's inode.
* Note that we use open_exec() as the name is now in kernel
* space, and we don't need to copy it.
*/
file = open_exec(interp);
if (IS_ERR(file))
return PTR_ERR(file);
bprm->file = file;
retval = prepare_binprm(bprm);
if (retval < 0)
return retval;
return search_binary_handler(bprm, regs);
}
static struct linux_binfmt em86_format = {
.module = THIS_MODULE,
.load_binary = load_em86,
};
static int __init init_em86_binfmt(void)
{
return register_binfmt(&em86_format);
}
static void __exit exit_em86_binfmt(void)
{
unregister_binfmt(&em86_format);
}
core_initcall(init_em86_binfmt);
module_exit(exit_em86_binfmt);
MODULE_LICENSE("GPL");
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