From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 460F1C25B74 for ; Mon, 27 May 2024 04:25:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BDDB66B0082; Mon, 27 May 2024 00:25:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B664F6B0083; Mon, 27 May 2024 00:25:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A06526B0085; Mon, 27 May 2024 00:25:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 82DA56B0082 for ; Mon, 27 May 2024 00:25:58 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id E9C89810F8 for ; 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imf04.hostedemail.com; dkim=none; spf=pass (imf04.hostedemail.com: domain of byungchul@sk.com designates 166.125.252.92 as permitted sender) smtp.mailfrom=byungchul@sk.com; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1716783956; a=rsa-sha256; cv=none; b=M4tkezJ1VZON7nS7wRRsIRgkziSh5p0aMu3b9lEarWyrxII2Wj1EBwA2l8G68aAbrjDMi9 v4at6WZ+a+U0dUG0RVMhM2ZkHoCIsg8ehntmfcq4UbCAeGLLKQKVWRlbz7O8mtArbmvjw5 Y7qnfCbJ8s9mWMQ5Y2AQdDmo/9AAzek= X-AuditID: a67dfc5b-d6dff70000001748-3b-66540b51522c Date: Mon, 27 May 2024 13:25:48 +0900 From: Byungchul Park To: Dave Hansen Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel_team@skhynix.com, akpm@linux-foundation.org, ying.huang@intel.com, vernhao@tencent.com, mgorman@techsingularity.net, hughd@google.com, willy@infradead.org, david@redhat.com, peterz@infradead.org, luto@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, rjgolo@gmail.com Subject: Re: [PATCH v10 00/12] LUF(Lazy Unmap Flush) reducing tlb numbers over 90% Message-ID: <20240527042548.GD12937@system.software.com> References: <20240510065206.76078-1-byungchul@sk.com> <982317c0-7faa-45f0-82a1-29978c3c9f4d@intel.com> <20240527015732.GA61604@system.software.com> <20240527034614.GA12937@system.software.com> <20240527041946.GC12937@system.software.com> MIME-Version: 1.0 Content-Type: text/plain; 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Just > > > tweaking the VFS or mmap() code likely isn't going to cut it. > > What a stupid idiot I am. > > I already discuss the exact cases with Nadav Amit at the very beginning > around v1. I didn't remember it when I was answering to you. > > mmap() or changing the permission by user already performs TLB flush > needed within that code, which LUF never touch. > > Worth noting currently LUF touchs only unmapping during migration or > reclaim. Other updating mapping would perform TLB flush it needs, as is. > I guess updating page cache is also already perform TLB flush needed. This may not be the case tho.. I might need to work on page cache. Byungchul > I need to check it. Probably, it would already do. > > Byungchul > > > LUF is interested in limited folios that are migratable or reclaimable > > in lru for now. So, IMHO, fixing a few things is going to cut it. > > > > > I guess we'll see what you come up with next, but this email was really > > > just the result of Vlastimil and I chatting on IRC for five minutes > > > about this set. > > > > > > It has absolutely not been tested nor reviewed enough. I hope the > > > performance gains stick around once more of the bugs are gone. > > > > Sure. It should be. > > > > Byungchul