From b6b19f25f69149c0912788fb81466dd2310bb095 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Wed, 19 Dec 2012 17:44:29 -0800 Subject: ksm: make rmap walks more scalable The rmap walks in ksm.c are like those in rmap.c: they can safely be done with anon_vma_lock_read(). Signed-off-by: Hugh Dickins Acked-by: Mel Gorman Signed-off-by: Linus Torvalds --- mm/ksm.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/mm/ksm.c b/mm/ksm.c index 82dfb4b5432..51573858938 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -1624,7 +1624,7 @@ again: struct anon_vma_chain *vmac; struct vm_area_struct *vma; - anon_vma_lock_write(anon_vma); + anon_vma_lock_read(anon_vma); anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, 0, ULONG_MAX) { vma = vmac->vma; @@ -1648,7 +1648,7 @@ again: if (!search_new_forks || !mapcount) break; } - anon_vma_unlock(anon_vma); + anon_vma_unlock_read(anon_vma); if (!mapcount) goto out; } @@ -1678,7 +1678,7 @@ again: struct anon_vma_chain *vmac; struct vm_area_struct *vma; - anon_vma_lock_write(anon_vma); + anon_vma_lock_read(anon_vma); anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, 0, ULONG_MAX) { vma = vmac->vma; @@ -1697,11 +1697,11 @@ again: ret = try_to_unmap_one(page, vma, rmap_item->address, flags); if (ret != SWAP_AGAIN || !page_mapped(page)) { - anon_vma_unlock(anon_vma); + anon_vma_unlock_read(anon_vma); goto out; } } - anon_vma_unlock(anon_vma); + anon_vma_unlock_read(anon_vma); } if (!search_new_forks++) goto again; @@ -1731,7 +1731,7 @@ again: struct anon_vma_chain *vmac; struct vm_area_struct *vma; - anon_vma_lock_write(anon_vma); + anon_vma_lock_read(anon_vma); anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, 0, ULONG_MAX) { vma = vmac->vma; @@ -1749,11 +1749,11 @@ again: ret = rmap_one(page, vma, rmap_item->address, arg); if (ret != SWAP_AGAIN) { - anon_vma_unlock(anon_vma); + anon_vma_unlock_read(anon_vma); goto out; } } - anon_vma_unlock(anon_vma); + anon_vma_unlock_read(anon_vma); } if (!search_new_forks++) goto again; -- cgit v1.2.3