Received-SPF: pass (google.com: domain of linux-kernel+bounces-204603-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) client-ip=147.75.48.161;
From: Zi Yan <ziy@nvidia.com>
To: "Pankaj Raghav (Samsung)" <kernel@pankajraghav.com>
Cc: Shuah Khan <shuah@kernel.org>, Andrew Morton <akpm@linux-foundation.org>,
 linux-mm@kvack.org, gost.dev@samsung.com, mcgrof@kernel.org,
 willy@infradead.org, linux-kernel@vger.kernel.org,
 linux-kselftest@vger.kernel.org, Pankaj Raghav <p.raghav@samsung.com>
Subject: Re: [PATCH v2] selftests/mm: use global variable to not optimize mmap
 read variable
Date: Thu, 06 Jun 2024 08:47:08 -0700
Message-ID: <744C4689-62F4-4565-988D-010824F4AB86@nvidia.com>
In-Reply-To: <20240606154428.672643-1-kernel@pankajraghav.com>
References: <20240606154428.672643-1-kernel@pankajraghav.com>
Content-Type: multipart/signed;
 boundary="=_MailMate_1A98BCE4-F926-4E16-97A0-2C5DFDD51BEB_=";
 micalg=pgp-sha512; protocol="application/pgp-signature"
Precedence: bulk
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0:
	=?us-ascii?Q?Kx4Auz9Hr1D3n/aF5dfdaT2tHzyZ5CItqGPnR/24xvstCv+1D2ecT0CkMA/r?=
 =?us-ascii?Q?bXYXcV2TwvQJv64MAfe0wAvJe9g2NZ5a6eD3bI/3Rs4ZVjxq/3iKKsEcM3fT?=
 =?us-ascii?Q?Ogonq5EzNdDvhIv+mrBLVR415ioJYvYRR7yyXZZw32jNkqw2ffiGThimEtcQ?=
 =?us-ascii?Q?HH0/ft2C9sB+2sGTntjSi2yLrrJ21a3G0x8VO1qz8UYBdcHAX9mHNFtdv5a4?=
 =?us-ascii?Q?NGl+VHQnFdOtAT2l9VfW0OpVXvBRIT1N0dBkSYXfkPtsk5cDZj5dAs37Xofk?=
 =?us-ascii?Q?RC1ZZ831mhJJpYmhXx7wmGltVFceYvKUUAthFkq4wumk/DdW94cmjnthB7rh?=
 =?us-ascii?Q?RwPpcJdUIBC7yC7HaXQNjb3L31RC+3wlx7BXDC3KpSSC4SJMyRdK9QFDjyBE?=
 =?us-ascii?Q?IoyLjeKIrcci1idm5Nw79EGu60xH81jixhCs4bC59vt7ADbfpbn/WYcCQZmm?=
 =?us-ascii?Q?DzLvmi4Bb0YHbvsvaddWJqJMeS5/B2Poz9WrF6+eJgTB+Cv5DHjybzszmUXs?=
 =?us-ascii?Q?FWrR8iHmEXvYasbxsoGsrZVE9yccTWFI94eBC0PYOMjIxwaahGnLfPSZtwLy?=
 =?us-ascii?Q?h4Vn3VA87Ych6Kqu3rLqK+OvoQc3Yuyl2EvILB+kIlIs4hxTzfmmoNm9kvxB?=
 =?us-ascii?Q?8JG+w4St4H2EBVMP1Q4DkxlST3K3bcsIMTCMD1lUtnvNzliKwzhu+8M9rAZd?=
 =?us-ascii?Q?1F1IDvd1IRyT+VmSBJNyzKAcc97XcuFmgfkLkwZOXrPEC1Fd0EovqPASKKJT?=
 =?us-ascii?Q?2zTYJlQQzqRX42+u1JV4v0s8MQZyobX1aamSswmfuPnenp3ywW0LvPSzFgBV?=
 =?us-ascii?Q?yZyApWVXFie4nouTJfiT7bd8BN4hjD9//V5UaLDj/D04iaJUmEELb4yPoB6W?=
 =?us-ascii?Q?VbQMvNQ0lxUWXhhU56oDKW9rcyZMG9ggR/9rrI1LdKcDccSmiSMqzOBF0NZO?=
 =?us-ascii?Q?VychM1Xp/TZ/nRxz1C8d8DFbSeDeo83urTJWM+erbcxByj8F6WMc+LCIbHkp?=
 =?us-ascii?Q?LC+ktQE0QaeSot4sOL6cUYPIv1NGkxZignozPf4KLpC64VqY/qR0GaN+NbGV?=
 =?us-ascii?Q?UKgWij5tNbI1qKEbPKLjV8BTbCdEp3phD3lvuJbmVSkprUvWo6VBMzieWt03?=
 =?us-ascii?Q?f77DDlgz5ljaDk6r2hiQbAIU3h7LybUpuiFbBcMfH0KmI71MFCXC7NhmHBrB?=
 =?us-ascii?Q?qQk8DqmvIiS38FiHIY0/9OOotjsvC09MhFkvqwCI7RwtiLJ8iLDwRkp6oXp7?=
 =?us-ascii?Q?6P4ZB3IzI0hcZRdgtBPdmYnBr61PE67qYJVonpyyuzicmf3uwiyP4hHHguc9?=
 =?us-ascii?Q?psuspZFAPkpdy/MJZHF+oF7mMZjgccqA0Tuk83yOVCNiWGv8OP4VZqr7x7SG?=
 =?us-ascii?Q?xhv+/22uqYX1+NzTzvjbRfXjvcHMn+qdiKDsiruXBGajznKpO+eY9cwn0nZu?=
 =?us-ascii?Q?k+eP3/CpsXri60RaSCx5GX+1ZG/eTWplsrlBCaEvxE3h6hra0S8OHek7FTMM?=
 =?us-ascii?Q?OmJaDrL7qDKxruYSuhKolnhY2RBCXCxzTaT6gSAFfhnv73pm+n8aMh++adBa?=
 =?us-ascii?Q?rx2xxu+tluNKIwBTyu4=3D?=
X-OriginatorOrg: Nvidia.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 537fb452-baa4-473e-ef91-08dc863fef05
X-MS-Exchange-CrossTenant-AuthSource: DS7PR12MB5744.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Jun 2024 15:47:13.2097
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: fDn0kDBfLEz1bAhLWjEvgk55gFdWG22w2WCILWDndq1JWtX7xvRWQ5do5IRkvRix
X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR12MB7261

--=_MailMate_1A98BCE4-F926-4E16-97A0-2C5DFDD51BEB_=
Content-Type: text/plain

On 6 Jun 2024, at 8:44, Pankaj Raghav (Samsung) wrote:

> From: Pankaj Raghav <p.raghav@samsung.com>
>
> create_pagecache_thp_and_fd() in split_huge_page_test.c used the
> variable dummy to perform mmap read.
>
> However, this test was skipped even on XFS which has large folio
> support. The issue was compiler (gcc 13.2.0) was optimizing out the
> dummy variable, therefore, not creating huge page in the page cache.
>
> Make it as a global variable to force the compiler not to optimize out
> the loop where we read from the mmaped addr.
>
> Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
> ---
> Changes since v1:
> - Make the dummy variable as a global variable(willy).
>
>  tools/testing/selftests/mm/split_huge_page_test.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>

Reviewed-by: Zi Yan <ziy@nvidia.com>

Thanks.

Best Regards,
Yan, Zi

--=_MailMate_1A98BCE4-F926-4E16-97A0-2C5DFDD51BEB_=
Content-Description: OpenPGP digital signature
Content-Disposition: attachment; filename=signature.asc
Content-Type: application/pgp-signature; name=signature.asc

-----BEGIN PGP SIGNATURE-----
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=+DVO
-----END PGP SIGNATURE-----

--=_MailMate_1A98BCE4-F926-4E16-97A0-2C5DFDD51BEB_=--