Message-ID: <498307e2-3952-801b-4847-1255214f5c76@suse.cz>
Date:   Tue, 21 Mar 2023 08:48:30 +0100
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Subject: Re: [PATCH 01/10] sparc/mm: Fix MAX_ORDER usage in tsb_grow()
To:     "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mel Gorman <mgorman@suse.de>,
        David Hildenbrand <david@redhat.com>
Cc:     linux-mm@kvack.org, linux-arch@vger.kernel.org,
        linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org,
        David Miller <davem@davemloft.net>
References: <20230315113133.11326-1-kirill.shutemov@linux.intel.com>
 <20230315113133.11326-2-kirill.shutemov@linux.intel.com>
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From:   Vlastimil Babka <vbabka@suse.cz>
In-Reply-To: <20230315113133.11326-2-kirill.shutemov@linux.intel.com>
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On 3/15/23 12:31, Kirill A. Shutemov wrote:
> MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
> can deliver is MAX_ORDER-1.
> 
> Fix MAX_ORDER usage in tsb_grow().
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

> Cc: sparclinux@vger.kernel.org
> Cc: David Miller <davem@davemloft.net>
> ---
>  arch/sparc/mm/tsb.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c
> index 912205787161..dba8dffe2113 100644
> --- a/arch/sparc/mm/tsb.c
> +++ b/arch/sparc/mm/tsb.c
> @@ -402,8 +402,8 @@ void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
>  	unsigned long new_rss_limit;
>  	gfp_t gfp_flags;
>  
> -	if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
> -		max_tsb_size = (PAGE_SIZE << MAX_ORDER);
> +	if (max_tsb_size > (PAGE_SIZE << (MAX_ORDER - 1)))
> +		max_tsb_size = (PAGE_SIZE << (MAX_ORDER - 1));
>  
>  	new_cache_index = 0;
>  	for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {