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Fri, 22 Oct 2021 23:57:18 +0000 Subject: Re: [PATCH 4/4] hugetlb: Remove redundant VM_BUG_ON() in add_reservation_in_range() To: Baolin Wang , akpm@linux-foundation.org Cc: mhocko@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <2b565552f3d06753da1e8dda439c0d96d6d9a5a3.1634797639.git.baolin.wang@linux.alibaba.com> From: Mike Kravetz Message-ID: <54e7cc45-dc11-b969-98b2-fd0825012426@oracle.com> Date: Fri, 22 Oct 2021 16:57:15 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 In-Reply-To: <2b565552f3d06753da1e8dda439c0d96d6d9a5a3.1634797639.git.baolin.wang@linux.alibaba.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MWHPR04CA0068.namprd04.prod.outlook.com (2603:10b6:300:6c::30) To BY5PR10MB4196.namprd10.prod.outlook.com (2603:10b6:a03:20d::23) MIME-Version: 1.0 Received: from [192.168.2.123] (50.38.35.18) by MWHPR04CA0068.namprd04.prod.outlook.com (2603:10b6:300:6c::30) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4628.15 via Frontend Transport; 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dkim=pass header.d=oracle.com header.s=corp-2021-07-09 header.b=CEoNGsPT; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b="iN+kJ/d+"; dmarc=pass (policy=none) header.from=oracle.com; spf=none (imf20.hostedemail.com: domain of mike.kravetz@oracle.com has no SPF policy when checking 205.220.177.32) smtp.mailfrom=mike.kravetz@oracle.com X-HE-Tag: 1634947040-977330 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 10/20/21 11:31 PM, Baolin Wang wrote: > When calling hugetlb_resv_map_add(), we've guaranteed that the parameter > 'to' is always larger than 'from', so it never returns a negative value > from hugetlb_resv_map_add(). Thus remove the redundant VM_BUG_ON(). > > Signed-off-by: Baolin Wang > --- > mm/hugetlb.c | 1 - > 1 file changed, 1 deletion(-) Thanks! You are correct, we could never trigger that VM_BUG_ON. Reviewed-by: Mike Kravetz -- Mike Kravetz > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 5922629..166cfa1 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -446,7 +446,6 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t, > add += hugetlb_resv_map_add(resv, rg, last_accounted_offset, > t, h, h_cg, regions_needed); > > - VM_BUG_ON(add < 0); > return add; > } > >