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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, "Hugh Dickins" <hughd@google.com>,
        "Andrea Arcangeli" <aarcange@redhat.com>,
        "Petr Holasek" <pholasek@redhat.com>,
        "Linus Torvalds" <torvalds@linux-foundation.org>,
        "Davidlohr Bueso" <dbueso@suse.de>
Date:   Sun, 11 Nov 2018 19:49:05 +0000
Message-ID: <lsq.1541965745.846937649@decadent.org.uk>
Subject: [PATCH 3.16 135/366] ksm: add cond_resched() to the rmap_walks
In-Reply-To: <lsq.1541965744.387173642@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Andrea Arcangeli <aarcange@redhat.com>

commit ad12695f177c3403a64348b42718faf9727fe358 upstream.

While at it add it to the file and anon walks too.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Petr Holasek <pholasek@redhat.com>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 mm/ksm.c  | 2 ++
 mm/rmap.c | 4 ++++
 2 files changed, 6 insertions(+)

--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1915,9 +1915,11 @@ again:
 		struct anon_vma_chain *vmac;
 		struct vm_area_struct *vma;
 
+		cond_resched();
 		anon_vma_lock_read(anon_vma);
 		anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root,
 					       0, ULONG_MAX) {
+			cond_resched();
 			vma = vmac->vma;
 			if (rmap_item->address < vma->vm_start ||
 			    rmap_item->address >= vma->vm_end)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1486,6 +1486,8 @@ static int rmap_walk_anon(struct page *p
 		struct vm_area_struct *vma = avc->vma;
 		unsigned long address = vma_address(page, vma);
 
+		cond_resched();
+
 		if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg))
 			continue;
 
@@ -1533,6 +1535,8 @@ static int rmap_walk_file(struct page *p
 	vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
 		unsigned long address = vma_address(page, vma);
 
+		cond_resched();
+
 		if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg))
 			continue;