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mm: new arch_remap() hook

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Some architectures would like to be triggered when a memory area is moved
through the mremap system call.

This patch introduces a new arch_remap() mm hook which is placed in the
path of mremap, and is called before the old area is unmapped (and the
arch_unmap() hook is called).

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Laurent Dufour 2015-06-24 16:56:19 -07:00 committed by Linus Torvalds
parent 2ae416b142
commit 4abad2ca4a
2 changed files with 20 additions and 6 deletions
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9
include/linux/mm-arch-hooks.h
View File

@ -13,4 +13,13 @@
#include <asm/mm-arch-hooks.h>
#ifndef arch_remap
static inline void arch_remap(struct mm_struct *mm,
unsigned long old_start, unsigned long old_end,
unsigned long new_start, unsigned long new_end)
{
}
#define arch_remap arch_remap
#endif
#endif /* _LINUX_MM_ARCH_HOOKS_H */

17
mm/mremap.c
View File

@ -22,6 +22,7 @@
#include <linux/mmu_notifier.h>
#include <linux/sched/sysctl.h>
#include <linux/uaccess.h>
#include <linux/mm-arch-hooks.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
@ -286,13 +287,17 @@ static unsigned long move_vma(struct vm_area_struct *vma,
old_len = new_len;
old_addr = new_addr;
new_addr = -ENOMEM;
} else if (vma->vm_file && vma->vm_file->f_op->mremap) {
err = vma->vm_file->f_op->mremap(vma->vm_file, new_vma);
if (err < 0) {
move_page_tables(new_vma, new_addr, vma, old_addr,
moved_len, true);
return err;
} else {
if (vma->vm_file && vma->vm_file->f_op->mremap) {
err = vma->vm_file->f_op->mremap(vma->vm_file, new_vma);
if (err < 0) {
move_page_tables(new_vma, new_addr, vma,
old_addr, moved_len, true);
return err;
}
}
arch_remap(mm, old_addr, old_addr + old_len,
new_addr, new_addr + new_len);
}
/* Conceal VM_ACCOUNT so old reservation is not undone */