Re: [PATCH 1/6] nommu: sort mm->mmap list properly
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2011-03-31 18:52:19
Also in:
lkml
On Mon, 28 Mar 2011 22:56:42 +0900 Namhyung Kim [off-list ref] wrote:
quoted hunk ↗ jump to hunk
@vma added into @mm should be sorted by start addr, end addr and VMA struct addr in that order because we may get identical VMAs in the @mm. However this was true only for the rbtree, not for the list. This patch fixes this by remembering 'rb_prev' during the tree traversal like find_vma_prepare() does and linking the @vma via __vma_link_list(). After this patch, we can iterate the whole VMAs in correct order simply by using @mm->mmap list. Signed-off-by: Namhyung Kim <redacted> --- mm/nommu.c | 62 ++++++++++++++++++++++++++++++++++++++--------------------- 1 files changed, 40 insertions(+), 22 deletions(-)diff --git a/mm/nommu.c b/mm/nommu.c index e7dbd3fae187..20d9c330eb0e 100644 --- a/mm/nommu.c +++ b/mm/nommu.c@@ -672,6 +672,30 @@ static void protect_vma(struct vm_area_struct *vma, unsigned long flags) #endif } +/* borrowed from mm/mmap.c */ +static inline void +__vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, + struct vm_area_struct *prev, struct rb_node *rb_parent) +{ + struct vm_area_struct *next; + + vma->vm_prev = prev; + if (prev) { + next = prev->vm_next; + prev->vm_next = vma; + } else { + mm->mmap = vma; + if (rb_parent) + next = rb_entry(rb_parent, + struct vm_area_struct, vm_rb); + else + next = NULL; + } + vma->vm_next = next; + if (next) + next->vm_prev = vma; +}
Duplicating code is rather bad. And putting random vma functions into mm/util.c is pretty ugly too, but I suppose it's less bad. mm/internal.h | 4 ++++ mm/mmap.c | 22 ---------------------- mm/nommu.c | 24 ------------------------ mm/util.c | 24 ++++++++++++++++++++++++ 4 files changed, 28 insertions(+), 46 deletions(-) diff -puN mm/nommu.c~mm-nommu-sort-mm-mmap-list-properly-fix mm/nommu.c
--- a/mm/nommu.c~mm-nommu-sort-mm-mmap-list-properly-fix
+++ a/mm/nommu.c@@ -672,30 +672,6 @@ static void protect_vma(struct vm_area_s #endif } -/* borrowed from mm/mmap.c */ -static inline void -__vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, - struct vm_area_struct *prev, struct rb_node *rb_parent) -{ - struct vm_area_struct *next; - - vma->vm_prev = prev; - if (prev) { - next = prev->vm_next; - prev->vm_next = vma; - } else { - mm->mmap = vma; - if (rb_parent) - next = rb_entry(rb_parent, - struct vm_area_struct, vm_rb); - else - next = NULL; - } - vma->vm_next = next; - if (next) - next->vm_prev = vma; -} - /* * add a VMA into a process's mm_struct in the appropriate place in the list * and tree and add to the address space's page tree also if not an anonymous
diff -puN mm/util.c~mm-nommu-sort-mm-mmap-list-properly-fix mm/util.c
--- a/mm/util.c~mm-nommu-sort-mm-mmap-list-properly-fix
+++ a/mm/util.c@@ -6,6 +6,8 @@ #include <linux/sched.h> #include <asm/uaccess.h> +#include "internal.h" + #define CREATE_TRACE_POINTS #include <trace/events/kmem.h>
@@ -215,6 +217,28 @@ char *strndup_user(const char __user *s, } EXPORT_SYMBOL(strndup_user); +void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, + struct vm_area_struct *prev, struct rb_node *rb_parent) +{ + struct vm_area_struct *next; + + vma->vm_prev = prev; + if (prev) { + next = prev->vm_next; + prev->vm_next = vma; + } else { + mm->mmap = vma; + if (rb_parent) + next = rb_entry(rb_parent, + struct vm_area_struct, vm_rb); + else + next = NULL; + } + vma->vm_next = next; + if (next) + next->vm_prev = vma; +} + #if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT) void arch_pick_mmap_layout(struct mm_struct *mm) {
diff -puN mm/internal.h~mm-nommu-sort-mm-mmap-list-properly-fix mm/internal.h
--- a/mm/internal.h~mm-nommu-sort-mm-mmap-list-properly-fix
+++ a/mm/internal.h@@ -66,6 +66,10 @@ static inline unsigned long page_order(s return page_private(page); } +/* mm/util.c */ +void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, + struct vm_area_struct *prev, struct rb_node *rb_parent); + #ifdef CONFIG_MMU extern long mlock_vma_pages_range(struct vm_area_struct *vma, unsigned long start, unsigned long end);
diff -puN mm/mmap.c~mm-nommu-sort-mm-mmap-list-properly-fix mm/mmap.c
--- a/mm/mmap.c~mm-nommu-sort-mm-mmap-list-properly-fix
+++ a/mm/mmap.c@@ -398,28 +398,6 @@ find_vma_prepare(struct mm_struct *mm, u return vma; } -void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, - struct vm_area_struct *prev, struct rb_node *rb_parent) -{ - struct vm_area_struct *next; - - vma->vm_prev = prev; - if (prev) { - next = prev->vm_next; - prev->vm_next = vma; - } else { - mm->mmap = vma; - if (rb_parent) - next = rb_entry(rb_parent, - struct vm_area_struct, vm_rb); - else - next = NULL; - } - vma->vm_next = next; - if (next) - next->vm_prev = vma; -} - void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, struct rb_node **rb_link, struct rb_node *rb_parent) {
_ -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>