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From:   Alex Ghiti <alex@ghiti.fr>
To:     Alexandre Ghiti <alex@ghiti.fr>
Cc:     "James E . J . Bottomley" <james.bottomley@hansenpartnership.com>,
        Helge Deller <deller@gmx.de>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Rich Felker <dalias@libc.org>,
        "David S . Miller" <davem@davemloft.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H . Peter Anvin" <hpa@zytor.com>, x86@kernel.org,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        linux-parisc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-s390@vger.kernel.org, linux-sh@vger.kernel.org,
        sparclinux@vger.kernel.org, linux-mm@kvack.org,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH RESEND 1/8] s390: Start fallback of top-down mmap at
 mm->mmap_base
References: <20190619054224.5983-1-alex@ghiti.fr>
 <20190619054224.5983-2-alex@ghiti.fr>
Message-ID: <4fcd8c83-dc33-12ab-3ba2-85a8d851674d@ghiti.fr>
Date:   Wed, 19 Jun 2019 01:54:20 -0400
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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)