Subject: + mm-rearrange-madvise-code-to-allow-for-reuse.patch added to -mm tree
To: ccross@xxxxxxxxxxx,dave.hansen@xxxxxxxxx,ebiederm@xxxxxxxxxxxx,gorcunov@xxxxxxxxxx,hannes@xxxxxxxxxxx,holt@xxxxxxx,hughd@xxxxxxxxxx,jan.glauber@xxxxxxxxx,john.stultz@xxxxxxxxxx,keescook@xxxxxxxxxxxx,mgorman@xxxxxxx,mingo@xxxxxxxxxx,oleg@xxxxxxxxxx,penberg@xxxxxxxxxx,peterz@xxxxxxxxxxxxx,riel@xxxxxxxxxx,rientjes@xxxxxxxxxx,rob@xxxxxxxxxxx,sasha.levin@xxxxxxxxxx,serge.hallyn@xxxxxxxxxx,shli@xxxxxxxxxxxx,tangchen@xxxxxxxxxxxxxx,viro@xxxxxxxxxxxxxxxxxx,walken@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 15 Oct 2013 14:28:45 -0700
The patch titled
Subject: mm: rearrange madvise code to allow for reuse
has been added to the -mm tree. Its filename is
mm-rearrange-madvise-code-to-allow-for-reuse.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-rearrange-madvise-code-to-allow-for-reuse.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-rearrange-madvise-code-to-allow-for-reuse.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Colin Cross <ccross@xxxxxxxxxxx>
Subject: mm: rearrange madvise code to allow for reuse
Refactor the madvise syscall to allow for parts of it to be reused by a
prctl syscall that affects vmas.
Move the code that walks vmas in a virtual address range into a function
that takes a function pointer as a parameter. The only caller for now is
sys_madvise, which uses it to call madvise_vma_behavior on each vma, but
the next patch will add an additional caller.
Move handling all vma behaviors inside madvise_behavior, and rename it to
madvise_vma_behavior.
Move the code that updates the flags on a vma, including splitting or
merging the vma as necessary, into a new function called
madvise_update_vma. The next patch will add support for updating a new
anon_name field as well.
Signed-off-by: Colin Cross <ccross@xxxxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Jan Glauber <jan.glauber@xxxxxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
Cc: Rob Landley <rob@xxxxxxxxxxx>
Cc: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: "Serge E. Hallyn" <serge.hallyn@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Michel Lespinasse <walken@xxxxxxxxxx>
Cc: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Cc: Robin Holt <holt@xxxxxxx>
Cc: Shaohua Li <shli@xxxxxxxxxxxx>
Cc: Sasha Levin <sasha.levin@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/madvise.c | 272 +++++++++++++++++++++++++++----------------------
1 file changed, 151 insertions(+), 121 deletions(-)
diff -puN mm/madvise.c~mm-rearrange-madvise-code-to-allow-for-reuse mm/madvise.c
--- a/mm/madvise.c~mm-rearrange-madvise-code-to-allow-for-reuse
+++ a/mm/madvise.c
@@ -39,65 +39,20 @@ static int madvise_need_mmap_write(int b
}
/*
- * We can potentially split a vm area into separate
- * areas, each area with its own behavior.
+ * Update the vm_flags on regiion of a vma, splitting it or merging it as
+ * necessary. Must be called with mmap_sem held for writing;
*/
-static long madvise_behavior(struct vm_area_struct *vma,
- struct vm_area_struct **prev,
- unsigned long start, unsigned long end, int behavior)
+static int madvise_update_vma(struct vm_area_struct *vma,
+ struct vm_area_struct **prev, unsigned long start,
+ unsigned long end, unsigned long new_flags)
{
struct mm_struct *mm = vma->vm_mm;
- int error = 0;
pgoff_t pgoff;
- unsigned long new_flags = vma->vm_flags;
-
- switch (behavior) {
- case MADV_NORMAL:
- new_flags = new_flags & ~VM_RAND_READ & ~VM_SEQ_READ;
- break;
- case MADV_SEQUENTIAL:
- new_flags = (new_flags & ~VM_RAND_READ) | VM_SEQ_READ;
- break;
- case MADV_RANDOM:
- new_flags = (new_flags & ~VM_SEQ_READ) | VM_RAND_READ;
- break;
- case MADV_DONTFORK:
- new_flags |= VM_DONTCOPY;
- break;
- case MADV_DOFORK:
- if (vma->vm_flags & VM_IO) {
- error = -EINVAL;
- goto out;
- }
- new_flags &= ~VM_DONTCOPY;
- break;
- case MADV_DONTDUMP:
- new_flags |= VM_DONTDUMP;
- break;
- case MADV_DODUMP:
- if (new_flags & VM_SPECIAL) {
- error = -EINVAL;
- goto out;
- }
- new_flags &= ~VM_DONTDUMP;
- break;
- case MADV_MERGEABLE:
- case MADV_UNMERGEABLE:
- error = ksm_madvise(vma, start, end, behavior, &new_flags);
- if (error)
- goto out;
- break;
- case MADV_HUGEPAGE:
- case MADV_NOHUGEPAGE:
- error = hugepage_madvise(vma, &new_flags, behavior);
- if (error)
- goto out;
- break;
- }
+ int error;
if (new_flags == vma->vm_flags) {
*prev = vma;
- goto out;
+ return 0;
}
pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
@@ -113,13 +68,13 @@ static long madvise_behavior(struct vm_a
if (start != vma->vm_start) {
error = split_vma(mm, vma, start, 1);
if (error)
- goto out;
+ return error;
}
if (end != vma->vm_end) {
error = split_vma(mm, vma, end, 0);
if (error)
- goto out;
+ return error;
}
success:
@@ -128,10 +83,7 @@ success:
*/
vma->vm_flags = new_flags;
-out:
- if (error == -ENOMEM)
- error = -EAGAIN;
- return error;
+ return 0;
}
#ifdef CONFIG_SWAP
@@ -337,6 +289,77 @@ static long madvise_remove(struct vm_are
return error;
}
+/*
+ * Apply an madvise behavior to a region of a vma. madvise_update_vma
+ * will handle splitting a vm area into separate areas, each area with its own
+ * behavior.
+ */
+static int madvise_vma_behavior(struct vm_area_struct *vma,
+ struct vm_area_struct **prev,
+ unsigned long start, unsigned long end,
+ unsigned long behavior)
+{
+ int error = 0;
+ unsigned long new_flags = vma->vm_flags;
+
+ switch (behavior) {
+ case MADV_REMOVE:
+ return madvise_remove(vma, prev, start, end);
+ case MADV_WILLNEED:
+ return madvise_willneed(vma, prev, start, end);
+ case MADV_DONTNEED:
+ return madvise_dontneed(vma, prev, start, end);
+ case MADV_NORMAL:
+ new_flags = new_flags & ~VM_RAND_READ & ~VM_SEQ_READ;
+ break;
+ case MADV_SEQUENTIAL:
+ new_flags = (new_flags & ~VM_RAND_READ) | VM_SEQ_READ;
+ break;
+ case MADV_RANDOM:
+ new_flags = (new_flags & ~VM_SEQ_READ) | VM_RAND_READ;
+ break;
+ case MADV_DONTFORK:
+ new_flags |= VM_DONTCOPY;
+ break;
+ case MADV_DOFORK:
+ if (vma->vm_flags & VM_IO) {
+ error = -EINVAL;
+ goto out;
+ }
+ new_flags &= ~VM_DONTCOPY;
+ break;
+ case MADV_DONTDUMP:
+ new_flags |= VM_DONTDUMP;
+ break;
+ case MADV_DODUMP:
+ if (new_flags & VM_SPECIAL) {
+ error = -EINVAL;
+ goto out;
+ }
+ new_flags &= ~VM_DONTDUMP;
+ break;
+ case MADV_MERGEABLE:
+ case MADV_UNMERGEABLE:
+ error = ksm_madvise(vma, start, end, behavior, &new_flags);
+ if (error)
+ goto out;
+ break;
+ case MADV_HUGEPAGE:
+ case MADV_NOHUGEPAGE:
+ error = hugepage_madvise(vma, &new_flags, behavior);
+ if (error)
+ goto out;
+ break;
+ }
+
+ error = madvise_update_vma(vma, prev, start, end, new_flags);
+
+out:
+ if (error == -ENOMEM)
+ error = -EAGAIN;
+ return error;
+}
+
#ifdef CONFIG_MEMORY_FAILURE
/*
* Error injection support for memory error handling.
@@ -375,22 +398,6 @@ static int madvise_hwpoison(int bhv, uns
}
#endif
-static long
-madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
- unsigned long start, unsigned long end, int behavior)
-{
- switch (behavior) {
- case MADV_REMOVE:
- return madvise_remove(vma, prev, start, end);
- case MADV_WILLNEED:
- return madvise_willneed(vma, prev, start, end);
- case MADV_DONTNEED:
- return madvise_dontneed(vma, prev, start, end);
- default:
- return madvise_behavior(vma, prev, start, end, behavior);
- }
-}
-
static int
madvise_behavior_valid(int behavior)
{
@@ -421,6 +428,73 @@ madvise_behavior_valid(int behavior)
}
/*
+ * Walk the vmas in range [start,end), and call the visit function on each one.
+ * The visit function will get start and end parameters that cover the overlap
+ * between the current vma and the original range. Any unmapped regions in the
+ * original range will result in this function returning -ENOMEM while still
+ * calling the visit function on all of the existing vmas in the range.
+ * Must be called with the mmap_sem held for reading or writing.
+ */
+static
+int madvise_walk_vmas(unsigned long start, unsigned long end,
+ unsigned long arg,
+ int (*visit)(struct vm_area_struct *vma,
+ struct vm_area_struct **prev, unsigned long start,
+ unsigned long end, unsigned long arg))
+{
+ struct vm_area_struct *vma;
+ struct vm_area_struct *prev;
+ unsigned long tmp;
+ int unmapped_error = 0;
+
+ /*
+ * If the interval [start,end) covers some unmapped address
+ * ranges, just ignore them, but return -ENOMEM at the end.
+ * - different from the way of handling in mlock etc.
+ */
+ vma = find_vma_prev(current->mm, start, &prev);
+ if (vma && start > vma->vm_start)
+ prev = vma;
+
+ for (;;) {
+ int error;
+
+ /* Still start < end. */
+ if (!vma)
+ return -ENOMEM;
+
+ /* Here start < (end|vma->vm_end). */
+ if (start < vma->vm_start) {
+ unmapped_error = -ENOMEM;
+ start = vma->vm_start;
+ if (start >= end)
+ break;
+ }
+
+ /* Here vma->vm_start <= start < (end|vma->vm_end) */
+ tmp = vma->vm_end;
+ if (end < tmp)
+ tmp = end;
+
+ /* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */
+ error = visit(vma, &prev, start, tmp, arg);
+ if (error)
+ return error;
+ start = tmp;
+ if (prev && start < prev->vm_end)
+ start = prev->vm_end;
+ if (start >= end)
+ break;
+ if (prev)
+ vma = prev->vm_next;
+ else /* madvise_remove dropped mmap_sem */
+ vma = find_vma(current->mm, start);
+ }
+
+ return unmapped_error;
+}
+
+/*
* The madvise(2) system call.
*
* Applications can use madvise() to advise the kernel how it should
@@ -464,9 +538,7 @@ madvise_behavior_valid(int behavior)
*/
SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
{
- unsigned long end, tmp;
- struct vm_area_struct *vma, *prev;
- int unmapped_error = 0;
+ unsigned long end;
int error = -EINVAL;
int write;
size_t len;
@@ -501,52 +573,10 @@ SYSCALL_DEFINE3(madvise, unsigned long,
else
down_read(¤t->mm->mmap_sem);
- /*
- * If the interval [start,end) covers some unmapped address
- * ranges, just ignore them, but return -ENOMEM at the end.
- * - different from the way of handling in mlock etc.
- */
- vma = find_vma_prev(current->mm, start, &prev);
- if (vma && start > vma->vm_start)
- prev = vma;
-
blk_start_plug(&plug);
- for (;;) {
- /* Still start < end. */
- error = -ENOMEM;
- if (!vma)
- goto out;
-
- /* Here start < (end|vma->vm_end). */
- if (start < vma->vm_start) {
- unmapped_error = -ENOMEM;
- start = vma->vm_start;
- if (start >= end)
- goto out;
- }
-
- /* Here vma->vm_start <= start < (end|vma->vm_end) */
- tmp = vma->vm_end;
- if (end < tmp)
- tmp = end;
-
- /* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */
- error = madvise_vma(vma, &prev, start, tmp, behavior);
- if (error)
- goto out;
- start = tmp;
- if (prev && start < prev->vm_end)
- start = prev->vm_end;
- error = unmapped_error;
- if (start >= end)
- goto out;
- if (prev)
- vma = prev->vm_next;
- else /* madvise_remove dropped mmap_sem */
- vma = find_vma(current->mm, start);
- }
-out:
+ error = madvise_walk_vmas(start, end, behavior, madvise_vma_behavior);
blk_finish_plug(&plug);
+
if (write)
up_write(¤t->mm->mmap_sem);
else
_
Patches currently in -mm which might be from ccross@xxxxxxxxxxx are
mm-rearrange-madvise-code-to-allow-for-reuse.patch
mm-add-a-field-to-store-names-for-private-anonymous-memory.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
