xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

mm: introduce mm_populate() for populating new vmas

Browse Source 
When creating new mappings using the MAP_POPULATE / MAP_LOCKED flags (or
with MCL_FUTURE in effect), we want to populate the pages within the
newly created vmas.  This may take a while as we may have to read pages
from disk, so ideally we want to do this outside of the write-locked
mmap_sem region.

This change introduces mm_populate(), which is used to defer populating
such mappings until after the mmap_sem write lock has been released.
This is implemented as a generalization of the former do_mlock_pages(),
which accomplished the same task but was using during mlock() /
mlockall().

Signed-off-by: Michel Lespinasse <walken@google.com>
Reported-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: Rik van Riel <riel@redhat.com>
Tested-by: Andy Lutomirski <luto@amacapital.net>
Cc: Greg Ungerer <gregungerer@westnet.com.au>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Michel Lespinasse
2013-02-22 16:32:37 -08:00
committed by Linus Torvalds
parent 940e7da516
commit bebeb3d68b
7 changed files with 62 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
include/linux/mm.h
View File

@@ -1474,11 +1474,23 @@ extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned lo
extern unsigned long mmap_region(struct file *file, unsigned long addr,
unsigned long len, unsigned long flags,
vm_flags_t vm_flags, unsigned long pgoff);
extern unsigned long do_mmap_pgoff(struct file *, unsigned long,
unsigned long, unsigned long,
unsigned long, unsigned long);
extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
unsigned long len, unsigned long prot, unsigned long flags,
unsigned long pgoff, bool *populate);
extern int do_munmap(struct mm_struct *, unsigned long, size_t);
#ifdef CONFIG_MMU
extern int __mm_populate(unsigned long addr, unsigned long len,
int ignore_errors);
static inline void mm_populate(unsigned long addr, unsigned long len)
{
/* Ignore errors */
(void) __mm_populate(addr, len, 1);
}
#else
static inline void mm_populate(unsigned long addr, unsigned long len) {}
#endif
/* These take the mm semaphore themselves */
extern unsigned long vm_brk(unsigned long, unsigned long);
extern int vm_munmap(unsigned long, size_t);