Date:   Wed, 15 Mar 2023 20:04:37 -0700
From:   Mike Kravetz <mike.kravetz@oracle.com>
To:     "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Mel Gorman <mgorman@suse.de>, Vlastimil Babka <vbabka@suse.cz>,
        David Hildenbrand <david@redhat.com>, linux-mm@kvack.org,
        linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
        sparclinux@vger.kernel.org, David Miller <davem@davemloft.net>
Subject: Re: [PATCH 01/10] sparc/mm: Fix MAX_ORDER usage in tsb_grow()
Message-ID: <20230316030437.GD3092@monkey>
References: <20230315113133.11326-1-kirill.shutemov@linux.intel.com>
 <20230315113133.11326-2-kirill.shutemov@linux.intel.com>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20230315113133.11326-2-kirill.shutemov@linux.intel.com>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?WtPxge8hek8NewzKznBe/PNZZ0bn+YHELfiBWI75RYNL723eH2b1IBjMJEuR?=
 =?us-ascii?Q?gYOfZiCvwe4F9NRcN2bptjB3YoXjtCzNMoluaQXoy8Tonvmzs4HRk9HAzrBn?=
 =?us-ascii?Q?TC7GvSALowhggo8o6R2JHlJrYejfvdkCvcN9Tn5GXXpMLlHqerrCVOWwYp/y?=
 =?us-ascii?Q?c2UcGQqNv84xjZ8uc7rOQvUrvWxJQ4/9UqHIcSz8IRHGzkq8YrHBxPIyEft5?=
 =?us-ascii?Q?CW4jpj5FTyfr3ZQ1PIglPs3HU69OhYNLlQx7OSLtpOQsfWv5QpsA1EQ0MAUl?=
 =?us-ascii?Q?ulnjo1T79wyTKUqXuUS2/wHmbMWEuThGyZk8jP9kAT4IqyvL6FGAA6jFY8KZ?=
 =?us-ascii?Q?IhCVAnD5OG+pjJew177F38RLKax4wStv0f0c2nPWbwfmx1SAvSHVQXb5fclU?=
 =?us-ascii?Q?3qU6Cm2aH1tmq+QSJfrxPhNUkl89KW6ch/BMj/zG/Eb8NWY+h0MfxP53ocKI?=
 =?us-ascii?Q?bJ/q3JCUVsO8DOyc/80FULtNQozDtixR7lAU+jceMSTvIqvIRdSvuy9qOSZu?=
 =?us-ascii?Q?5Hm6l/HtP50UtxIetCkB0B4T36pr+HMVe/dgnJLET/hJAAURy8I6S+5DvXxc?=
 =?us-ascii?Q?VT7juez4RLJxgu0lTaFzHuSog52u4+ScfJfydHeN7/BduFSctto4k6VyB2z2?=
 =?us-ascii?Q?VyOSp1exw3Ju06wCrbUp16tPlfKKGdpcqJjHg4/S9G/WRtpap+Q9KeKm2936?=
 =?us-ascii?Q?IDTGKvmzEa2DA5sSGO4Ir9wvoTSginmyTaP4IWlaLwKZc2OOAsSOmw4mThLn?=
 =?us-ascii?Q?2kCsEpD5glBwRkLUqnWVVTP6wR35FjXbYN21bSUp7JCaF5hqiD72J4ONoLmu?=
 =?us-ascii?Q?fwiLMqSRgl+S4/HQ50NVe1GFL2tR8LDurE3g43SA8sYd8rbLK74DG5rNgqJn?=
 =?us-ascii?Q?TkInYPSjvJbzD/GtmP88Sp9yQ8ZTqAr0R1QuhSHFIUcr+wNu0qgNd+hXURnN?=
 =?us-ascii?Q?hy30H76BCEwUc1Ky4PHHwJTqRfeHpKAaa2r5Hoi2pPbqbyXZm7nBlSuZUk0U?=
 =?us-ascii?Q?REeR9vyspAGE8s5M6PBOVSQwiSIX/OOqSdca00lTijk8O8gdop0/0cxh7Wqt?=
 =?us-ascii?Q?1fIyVOfcX0jl2w1JpuBZl7rTrrKLsH6Uu1U9aM9sIlo3JrcC8WcEzakEPsix?=
 =?us-ascii?Q?HaEPfoxwTl/vBg8dzSpqDJp5Dtw76b2NJP1Vm3ck9i5KcF81WK9bbn9jWrQV?=
 =?us-ascii?Q?EPJGZBDtPjCjxwxKtkRQ9qnsq/CWDi7ZFbhXffZPZPF97qkpwTR5pdnii5CC?=
 =?us-ascii?Q?RxXQyNc18OqWgbXJXwzX6bg1OypE0QfFYafY3fUBdIDHhncu51336joRs6FB?=
 =?us-ascii?Q?a9H8EoTtqfZMVx8mKzp3fMaH8KRdYIipxuUh0lt7fsMaIHyHxuOrMe73h1+w?=
 =?us-ascii?Q?2kiFUfOHUnZj1rg2taUu9RYEe8RoKX31nKswFUIRWk4AbTsPOVLoV4fGQS60?=
 =?us-ascii?Q?vDk27jrmFsrLwaDwu5DSKC+pkMzeOJjlXY5joYHWCY7f/vFDm6+NLccfT+IZ?=
 =?us-ascii?Q?HnZKBtBX9n5d7/mz3hssZDl6ZNMmo+l8ioZaAkZ0nKmHWHGGgPbHQMdoi+8c?=
 =?us-ascii?Q?zG0CWwx+d1FMlwCtrJhKss0Dn3r6uwHm0M8iJlmhr5vMwDtTNA8i7YzTsLc6?=
 =?us-ascii?Q?uw=3D=3D?=
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: =?us-ascii?Q?GE4F734VzrhR/Z//DKqVbRSeBfYcDcuJURxEfCpKijaKrxLr4t8DWjvQcVze?=
 =?us-ascii?Q?SGIRseJmLlWjNAya943PpdMA7+VYSROXfVQ0+CRxGYy303Y1NpK8xbWoGum3?=
 =?us-ascii?Q?ZC0PJEhrtduTImB6j6GKY4O4o4ulLwNSjkeR2XAzJF3TNrznztVbdfR9aH2R?=
 =?us-ascii?Q?IcsgMuizJYz4RTC6AONG4uk87Jpv6K2QPXD8cmET+fRRJwVslW0AW6maQ/jY?=
 =?us-ascii?Q?DlXciotJ4Wayn34lSvX81/IdOBJUBwh9Zkq9QBPT+BMBrIk5/0GKnM1SpsXi?=
 =?us-ascii?Q?tSGc7er1lp82zhlCJeZy9F6sKZHAAJLwnn8lLDVn8VnY3+eK0frWBj36e9Ka?=
 =?us-ascii?Q?YBta518C6FS0BLL+X4igVS/TwbIIyToD89Afv8yi0tlzpur+jUAZx7DibNKr?=
 =?us-ascii?Q?zrRNy7jzvYTVPRUUrn2NzVdE63wN5ZIS6Le7sZd9RbaHZl3duN8vggZouH6H?=
 =?us-ascii?Q?YOMIcPEIt61F4ux7enoTMiLwx+zgVJS028sWA79QyudmvBWHi8ztASeTgxRe?=
 =?us-ascii?Q?dMV3mBJVb+SIrumQ3dn1SYI6EAs+ydWymjYcNItaM6FO+3CcTJir6zWMbi38?=
 =?us-ascii?Q?pMFWaP2UMaiCzSOKTgrBQQlfM32UujYCcPCBpq/A9AtoRvzeUe7Gz+VMqUqK?=
 =?us-ascii?Q?ezMm/kvW2kKTI1LV2KWsR/RwHJ5fBC+lNeBuB9qOfY1eSVKYKbVsPpkBdzfb?=
 =?us-ascii?Q?fDcgu9t7qhu6IfR2skuARWYqm+AxLRZelWnlyFyW6SrGIsouYoLa2jCtozbw?=
 =?us-ascii?Q?Q2XObzzQ/8x4vV0THDZ4qm/AwLBR+Jj6Ae9gt+T68qsF9Bb6E02k3UShwtj2?=
 =?us-ascii?Q?4BiinVOkGLnGOcta8m/Q6rkjUwHi86Ub1rN0P6DKdeV/GZAIkGRLYXfr0oCj?=
 =?us-ascii?Q?TbnUNLmtkB0bUsj20ha4m/FVfjcHrwDGJZKCdo1sJeFl9tHj9L6oycL/R72Q?=
 =?us-ascii?Q?QL1IOFoCIlFR0M9Exa+eAvFub7lAS77vtTnMhVWup+WVrM6P1uYtWl0MgfAe?=
 =?us-ascii?Q?n5L9?=
X-OriginatorOrg: oracle.com
X-MS-Exchange-CrossTenant-Network-Message-Id: e2ae0d4e-44d3-4b58-5237-08db25cb2f95
X-MS-Exchange-CrossTenant-AuthSource: BY5PR10MB4196.namprd10.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Mar 2023 03:04:41.3554
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: JKFNhYuy7c2+NSmaptLEjXrtmfONdqBvQtuy86HVZ2Idl6PuJvM8jPCHGg8/AwHtPLHZS4LoW4c5cio5myowlA==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BLAPR10MB5011
X-Proofpoint-Virus-Version: vendor=baseguard
 engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22
 definitions=2023-03-16_02,2023-03-15_01,2023-02-09_01
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 mlxlogscore=999
 bulkscore=0 mlxscore=0 adultscore=0 suspectscore=0 phishscore=0
 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1
 engine=8.12.0-2303150002 definitions=main-2303160026
X-Proofpoint-ORIG-GUID: Xs8-lBl2PufyojZ7Zh0XbizyciDMv42f
X-Proofpoint-GUID: Xs8-lBl2PufyojZ7Zh0XbizyciDMv42f
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 03/15/23 14:31, 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>
> 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) {
> 

Fortunately, I think this only comes into play if MAX_ORDER <= 7.

Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
-- 
Mike Kravetz