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b=HXctiPqcixf5ofRlrw+62WSquXdeg/boIUpGLomwpKVj4626AgypM/t2M8rYDENXj YOkXcx/yKvz5/s4jyifY2mW1flXNaCsWvSYxmK0gJ7XjQNEiVZzlg2lfZ63gFBIv2E 4Oz02TVBb94YAw/BBhK3vlGdPOyluJGZrqi9pGjW+7sExI2po7aP2cIWvS3/isKdkW 0WFptr0QEHFyxDBlSQ/4PyZYGpJH4yc0808O02A8Xc/Fbe9m9Jc2n1pLypjpfsci9C J9KNBIVaIVCw2Ro1cSCuSHjrQQnsPTq1cFm9KpqdsnEbU4RAFdSE9UGrr5VIWJf7uh RUCtDOFmetuaA== Message-ID: Date: Tue, 21 Apr 2026 16:06:53 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] mm/page_alloc: use batch page clearing in kernel_init_pages() To: Zi Yan Cc: Hrushikesh Salunke , akpm@linux-foundation.org, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, rkodsara@amd.com, bharata@amd.com, ankur.a.arora@oracle.com, shivankg@amd.com References: <20260421042451.76918-1-hsalunke@amd.com> <23A49388-EF68-4055-B620-54FD92FF2EC8@nvidia.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 911CE140004 X-Stat-Signature: pnmo8bern9ju1qq661rsnzwud5dik5dn X-HE-Tag: 1776780420-131090 X-HE-Meta: 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 VuRJS3b5 cgxuIfMj7PZ9Wl7BWu9X+Ra3L/bZoPWENkNOkYMNvp8j0GGaG5oAvmk8kNxrsWZFGeWf5S+3hg2ZOt2lVZ0CMHSgcp4SWrA6LI5/mZqw5aST7BNm2dCPTOQCHFfIh/6BNQNVbrbIqiWhYrrcE76emyrYMdOjIwDJgDBjS3NpM4z0iK8/pFpA+Evoc6lEZPmNFAkKGt/2zxbyVj5yT6nd2gWMLerDJpQhABksRXsNpdP9ABlD6noYC9jSiNmZd6KbNuIkejD3oibCsExaXgJP5qRzttnk9o8loMrV8Odn7f0/9GR+U7yXWwno13A== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/21/26 16:03, Zi Yan wrote: > On 21 Apr 2026, at 9:57, David Hildenbrand (Arm) wrote: > >> On 4/21/26 15:44, Zi Yan wrote: >>> >>> >>> kasan_reset_tag() here removes the tag from page address, so that >>> clear_pages() can use the right kaddr. I thought each page needs >>> a kasan_reset_tag(). No need to respond here, as I am reading >>> the code and trying to understand how it works. >> >> It's all confusing. But we really just turn the pointer into an untagged >> pointer here, once. > > Yes, I realized that after reading kasan_reset_tag() implementation. > >> >> So I think this is ok. >> >> I do wonder, though, whether we want to move the >> kasan_disable_current/kasan_enable_current into the >> clear_highpages_kasan_tagged(). > > This sounds reasonable to me. And also replace kernel_init_pages() > with clear_highpages_kasan_tagged(), since kernel_init_pages() > will be a wrapper then. Agreed. -- Cheers, David