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 A85CDC25B74 for ; Mon, 27 May 2024 04:19:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EBEF46B0082; Mon, 27 May 2024 00:19:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E6DB56B0085; Mon, 27 May 2024 00:19:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D34FA6B0088; Mon, 27 May 2024 00:19:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id B4F8F6B0082 for ; Mon, 27 May 2024 00:19:56 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 5106F41170 for ; 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imf02.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf02.hostedemail.com: domain of byungchul@sk.com designates 166.125.252.92 as permitted sender) smtp.mailfrom=byungchul@sk.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1716783594; a=rsa-sha256; cv=none; b=4UAn1ry4NbuyCSBTPFgXZjvBrw3yNivQY6zFWABz6RMD3mL34BbWp+A1t8bcydfulqoDmY bjnwfDXrrIMX7R3fKTnUKdO7YoPDrHLHn2lGewChn0NKUor97lcXUyWlj3fnB9nvXFMOo2 tnu5dldmT5lSiHIpDqzoXdTLGHWs2Jc= X-AuditID: a67dfc5b-d85ff70000001748-7a-665409e87671 Date: Mon, 27 May 2024 13:19:46 +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: <20240527041946.GC12937@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> 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. 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