mm: new arch_remap() hook (4abad2ca) · Commits · 戴 / test

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>

include/linux/mm-arch-hooks.h

+9 −0

Original line number	Diff line number	Diff line
		@@ -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 */

mm/mremap.c

+11 −6

Original line number	Diff line number	Diff line
		@@ -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>
		@@ -286,14 +287,18 @@ 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) {
		} 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);
		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 */
		if (vm_flags & VM_ACCOUNT) {

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