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[RESEND,1/8] s390: Start fallback of top-down mmap at mm->mmap_base

Message ID 20190619054224.5983-2-alex@ghiti.fr (mailing list archive)
State Awaiting Upstream
Headers show
Series Fix mmap base in bottom-up mmap | expand

Commit Message

Alexandre Ghiti June 19, 2019, 5:42 a.m. UTC
In case of mmap failure in top-down mode, there is no need to go through
the whole address space again for the bottom-up fallback: the goal of this
fallback is to find, as a last resort, space between the top-down mmap base
and the stack, which is the only place not covered by the top-down mmap.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
---
 arch/s390/mm/mmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Alexandre Ghiti June 19, 2019, 5:54 a.m. UTC | #1
Really sorry about that, my connection is weird this morning, I'll retry 
tomorrow.

Sorry again,

Alex

On 6/19/19 1:42 AM, Alexandre Ghiti wrote:
> In case of mmap failure in top-down mode, there is no need to go through
> the whole address space again for the bottom-up fallback: the goal of this
> fallback is to find, as a last resort, space between the top-down mmap base
> and the stack, which is the only place not covered by the top-down mmap.
>
> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
> ---
>   arch/s390/mm/mmap.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
> index cbc718ba6d78..4a222969843b 100644
> --- a/arch/s390/mm/mmap.c
> +++ b/arch/s390/mm/mmap.c
> @@ -166,7 +166,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
>   	if (addr & ~PAGE_MASK) {
>   		VM_BUG_ON(addr != -ENOMEM);
>   		info.flags = 0;
> -		info.low_limit = TASK_UNMAPPED_BASE;
> +		info.low_limit = mm->mmap_base;
>   		info.high_limit = TASK_SIZE;
>   		addr = vm_unmapped_area(&info);
>   		if (addr & ~PAGE_MASK)
diff mbox series

Patch

diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index cbc718ba6d78..4a222969843b 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -166,7 +166,7 @@  arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	if (addr & ~PAGE_MASK) {
 		VM_BUG_ON(addr != -ENOMEM);
 		info.flags = 0;
-		info.low_limit = TASK_UNMAPPED_BASE;
+		info.low_limit = mm->mmap_base;
 		info.high_limit = TASK_SIZE;
 		addr = vm_unmapped_area(&info);
 		if (addr & ~PAGE_MASK)