From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 0F77F6B025E for ; Wed, 31 Aug 2016 11:03:30 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id 63so109666096pfx.0 for ; Wed, 31 Aug 2016 08:03:30 -0700 (PDT) Received: from foss.arm.com (foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id p63si258531pfp.244.2016.08.31.08.03.28 for ; Wed, 31 Aug 2016 08:03:28 -0700 (PDT) From: James Morse Subject: [PATCH] mm, proc: Make the task_mmu walk_page_range() limit in clear_refs_write() obvious Date: Wed, 31 Aug 2016 16:03:12 +0100 Message-Id: <1472655792-22439-1-git-send-email-james.morse@arm.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: Andrew Morton , James Morse , Naoya Horiguchi Trying to walk all of virtual memory requires architecture specific knowledge. On x86_64, addresses must be sign extended from bit 48, whereas on arm64 the top VA_BITS of address space have their own set of page tables. clear_refs_write() calls walk_page_range() on the range 0 to ~0UL, it provides a test_walk() callback that only expects to be walking over VMAs. Currently walk_pmd_range() will skip memory regions that don't have a VMA, reporting them as a hole. As this call only expects to walk user address space, make it walk 0 to 'highest_vm_end'. Signed-off-by: James Morse Cc: Naoya Horiguchi --- This is in preparation for a RFC series that allows walk_page_range() to walk kernel page tables too. fs/proc/task_mmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 187d84ef9de9..1026b7862896 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1068,7 +1068,7 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, } mmu_notifier_invalidate_range_start(mm, 0, -1); } - walk_page_range(0, ~0UL, &clear_refs_walk); + walk_page_range(0, mm->highest_vm_end, &clear_refs_walk); if (type == CLEAR_REFS_SOFT_DIRTY) mmu_notifier_invalidate_range_end(mm, 0, -1); flush_tlb_mm(mm); -- 2.8.0.rc3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org