As noticed by Xiao, since soft-dirty clear command modifies page tables we have to flush tlbs and call mmu notifiers. While the former is done by the clear_refs engine itself, the latter is to be done.
One thing to note about this -- in order not to call per-page invalidate notifier (_all_ address space is about to be changed), the _invalidate_range_start and _end are used. But for those start and end are not known exactly. To address this, the same trick as in exit_mmap() is used -- start is 0 and end is (unsigned long)-1. Signed-off-by: Pavel Emelyanov <[email protected]> --- diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 27453c0..dbf61f6 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -11,6 +11,7 @@ #include <linux/rmap.h> #include <linux/swap.h> #include <linux/swapops.h> +#include <linux/mmu_notifier.h> #include <asm/elf.h> #include <asm/uaccess.h> @@ -815,6 +816,8 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, .private = &cp, }; down_read(&mm->mmap_sem); + if (type == CLEAR_REFS_SOFT_DIRTY) + mmu_notifier_invalidate_range_start(mm, 0, -1); for (vma = mm->mmap; vma; vma = vma->vm_next) { cp.vma = vma; if (is_vm_hugetlb_page(vma)) @@ -835,6 +838,8 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, walk_page_range(vma->vm_start, vma->vm_end, &clear_refs_walk); } + if (type == CLEAR_REFS_SOFT_DIRTY) + mmu_notifier_invalidate_range_end(mm, 0, -1); flush_tlb_mm(mm); up_read(&mm->mmap_sem); mmput(mm); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
