On Wed, 16 Jun 2010 13:36:57 +0900 (JST)
KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> wrote:
>
> Now, migrate_pages() are using >500 bytes stack. This patch reduce it.
>
> mm/mempolicy.c: In function 'sys_migrate_pages':
> mm/mempolicy.c:1344: warning: the frame size of 528 bytes is larger than
> 512 bytes
>
> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
> Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
> ---
> mm/mempolicy.c | 35 ++++++++++++++++++++++-------------
> 1 files changed, 22 insertions(+), 13 deletions(-)
>
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 13b09bd..1116427 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -1275,33 +1275,39 @@ SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
> const unsigned long __user *, new_nodes)
> {
> const struct cred *cred = current_cred(), *tcred;
> - struct mm_struct *mm;
> + struct mm_struct *mm = NULL;
> struct task_struct *task;
> - nodemask_t old;
> - nodemask_t new;
> nodemask_t task_nodes;
> int err;
> + NODEMASK_SCRATCH(scratch);
> + nodemask_t *old = &scratch->mask1;
> + nodemask_t *new = &scratch->mask2;
>
> + if (!scratch)
> + return -ENOMEM;
It doesn't matter in practice, but it makes me all queazy to see code
which plays with pointers which might be NULL.
--- a/mm/mempolicy.c~mempolicy-reduce-stack-size-of-migrate_pages-fix
+++ a/mm/mempolicy.c
@@ -1279,13 +1279,16 @@ SYSCALL_DEFINE4(migrate_pages, pid_t, pi
struct task_struct *task;
nodemask_t task_nodes;
int err;
+ nodemask_t *old;
+ nodemask_t *new;
NODEMASK_SCRATCH(scratch);
- nodemask_t *old = &scratch->mask1;
- nodemask_t *new = &scratch->mask2;
if (!scratch)
return -ENOMEM;
+ old = &scratch->mask1;
+ new = &scratch->mask2;
+
err = get_nodes(old, old_nodes, maxnode);
if (err)
goto out;
_
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxxx For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>