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[91.12.103.101]) by smtp.gmail.com with ESMTPSA id s8sm13174651wra.9.2021.11.23.09.20.03 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 23 Nov 2021 09:20:03 -0800 (PST) Message-ID: Date: Tue, 23 Nov 2021 18:20:02 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [PATCH] mm: split thp synchronously on MADV_DONTNEED To: Shakeel Butt Cc: "Kirill A . Shutemov" , Yang Shi , Zi Yan , Matthew Wilcox , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20211120201230.920082-1-shakeelb@google.com> <25b36a5c-5bbd-5423-0c67-05cd6c1432a7@redhat.com> <1b30d06d-f9c0-1737-13e6-2d1a7d7b8507@redhat.com> <92fe0c31-b083-28c4-d306-da8a3cd891a3@redhat.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 28CB420019D3 X-Stat-Signature: s66hscnuc53jwt7ffwxrhmhazeufef4k Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=U6dYrGMz; spf=none (imf26.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 170.10.129.124) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-HE-Tag: 1637688007-57633 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 23.11.21 18:17, Shakeel Butt wrote: > On Tue, Nov 23, 2021 at 8:57 AM David Hildenbrand wrote: >> > [...] >>>> >>>> I do wonder which these locking contexts are exactly, and if we could >>>> also do the same thing on ordinary munmap -- because I assume it can be >>>> similarly problematic for some applications. >>> >>> This is a good question regarding munmap. One main difference is >>> munmap takes mmap_lock in write mode and usually performance critical >>> applications avoid such operations. >> >> Maybe we can extend it too most page zapping, if that makes things simpler. >> > > Do you mean doing sync THP split for most of page zapping functions > (but only if that makes things simpler)? > Yes -- if there are no downsides. -- Thanks, David / dhildenb