From ed8ea8150182f8d715fceb3b175ef0a9ebacd872 Mon Sep 17 00:00:00 2001 From: Michel Lespinasse Date: Mon, 8 Oct 2012 16:31:45 -0700 Subject: mm: add CONFIG_DEBUG_VM_RB build option Add a CONFIG_DEBUG_VM_RB build option for the previously existing DEBUG_MM_RB code. Now that Andi Kleen modified it to avoid using recursive algorithms, we can expose it a bit more. Also extend this code to validate_mm() after stack expansion, and to check that the vma's start and last pgoffs have not changed since the nodes were inserted on the anon vma interval tree (as it is important that the nodes be reindexed after each such update). Signed-off-by: Michel Lespinasse Cc: Andrea Arcangeli Cc: Rik van Riel Cc: Peter Zijlstra Cc: Daniel Santos Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/interval_tree.c | 41 ++++++++++++++++++++++++++++++++++++++++- mm/mmap.c | 19 +++++++++---------- 2 files changed, 49 insertions(+), 11 deletions(-) (limited to 'mm') diff --git a/mm/interval_tree.c b/mm/interval_tree.c index f7c72cd35e1d..4a5822a586e6 100644 --- a/mm/interval_tree.c +++ b/mm/interval_tree.c @@ -70,4 +70,43 @@ static inline unsigned long avc_last_pgoff(struct anon_vma_chain *avc) } INTERVAL_TREE_DEFINE(struct anon_vma_chain, rb, unsigned long, rb_subtree_last, - avc_start_pgoff, avc_last_pgoff,, anon_vma_interval_tree) + avc_start_pgoff, avc_last_pgoff, + static inline, __anon_vma_interval_tree) + +void anon_vma_interval_tree_insert(struct anon_vma_chain *node, + struct rb_root *root) +{ +#ifdef CONFIG_DEBUG_VM_RB + node->cached_vma_start = avc_start_pgoff(node); + node->cached_vma_last = avc_last_pgoff(node); +#endif + __anon_vma_interval_tree_insert(node, root); +} + +void anon_vma_interval_tree_remove(struct anon_vma_chain *node, + struct rb_root *root) +{ + __anon_vma_interval_tree_remove(node, root); +} + +struct anon_vma_chain * +anon_vma_interval_tree_iter_first(struct rb_root *root, + unsigned long first, unsigned long last) +{ + return __anon_vma_interval_tree_iter_first(root, first, last); +} + +struct anon_vma_chain * +anon_vma_interval_tree_iter_next(struct anon_vma_chain *node, + unsigned long first, unsigned long last) +{ + return __anon_vma_interval_tree_iter_next(node, first, last); +} + +#ifdef CONFIG_DEBUG_VM_RB +void anon_vma_interval_tree_verify(struct anon_vma_chain *node) +{ + WARN_ON_ONCE(node->cached_vma_start != avc_start_pgoff(node)); + WARN_ON_ONCE(node->cached_vma_last != avc_last_pgoff(node)); +} +#endif diff --git a/mm/mmap.c b/mm/mmap.c index 2e580ed79211..deb422c39e21 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -51,12 +51,6 @@ static void unmap_region(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_area_struct *prev, unsigned long start, unsigned long end); -/* - * WARNING: the debugging will use recursive algorithms so never enable this - * unless you know what you are doing. - */ -#undef DEBUG_MM_RB - /* description of effects of mapping type and prot in current implementation. * this is due to the limited x86 page protection hardware. The expected * behavior is in parens: @@ -303,7 +297,7 @@ out: return retval; } -#ifdef DEBUG_MM_RB +#ifdef CONFIG_DEBUG_VM_RB static int browse_rb(struct rb_root *root) { int i = 0, j; @@ -337,9 +331,12 @@ void validate_mm(struct mm_struct *mm) { int bug = 0; int i = 0; - struct vm_area_struct *tmp = mm->mmap; - while (tmp) { - tmp = tmp->vm_next; + struct vm_area_struct *vma = mm->mmap; + while (vma) { + struct anon_vma_chain *avc; + list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) + anon_vma_interval_tree_verify(avc); + vma = vma->vm_next; i++; } if (i != mm->map_count) @@ -1790,6 +1787,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address) } vma_unlock_anon_vma(vma); khugepaged_enter_vma_merge(vma); + validate_mm(vma->vm_mm); return error; } #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ @@ -1843,6 +1841,7 @@ int expand_downwards(struct vm_area_struct *vma, } vma_unlock_anon_vma(vma); khugepaged_enter_vma_merge(vma); + validate_mm(vma->vm_mm); return error; } -- cgit v1.2.3-55-g7522