On 26.1.2016 21:28, Kirill A. Shutemov wrote:
> From 396ad132be07a2d2b9ec5d1d6ec9fe2fffe8105e Mon Sep 17 00:00:00 2001
> From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
> Date: Tue, 26 Jan 2016 22:59:16 +0300
> Subject: [PATCH] sg: mark VMA as VM_IO to prevent migration
>
> Reduced testcase:
>
> #include <fcntl.h>
> #include <unistd.h>
> #include <sys/mman.h>
> #include <numaif.h>
>
> #define SIZE 0x2000
>
> int main()
> {
> int fd;
> void *p;
>
> fd = open("/dev/sg0", O_RDWR);
> p = mmap(NULL, SIZE, PROT_EXEC, MAP_PRIVATE | MAP_LOCKED, fd, 0);
> mbind(p, SIZE, 0, NULL, 0, MPOL_MF_MOVE);
> return 0;
> }
>
> We shouldn't try to migrate pages in sg VMA as we don't have a way to
> update Sg_scatter_hold::pages accordingly from mm core.
>
> Let's mark the VMA as VM_IO to indicate to mm core that the VMA is
> migratable.
^ not migratable.
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> ---
> drivers/scsi/sg.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
> index 503ab8b46c0b..5e820674432c 100644
> --- a/drivers/scsi/sg.c
> +++ b/drivers/scsi/sg.c
> @@ -1261,7 +1261,7 @@ sg_mmap(struct file *filp, struct vm_area_struct *vma)
> }
>
> sfp->mmap_called = 1;
> - vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
> + vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
> vma->vm_private_data = sfp;
> vma->vm_ops = &sg_mmap_vm_ops;
> return 0;
>
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