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 42A41C47074 for ; Tue, 2 Jan 2024 03:25:26 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7F62B6B020E; Mon, 1 Jan 2024 22:25:25 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7A5DB6B020F; Mon, 1 Jan 2024 22:25:25 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 695936B0213; Mon, 1 Jan 2024 22:25:25 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 5A87E6B020E for ; Mon, 1 Jan 2024 22:25:25 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 09F524071A for ; Tue, 2 Jan 2024 03:25:25 +0000 (UTC) X-FDA: 81632930610.19.EE3C7E9 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf20.hostedemail.com (Postfix) with ESMTP id 3EFDA1C000F for ; Tue, 2 Jan 2024 03:25:23 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b="eFpz/HwQ"; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf20.hostedemail.com: domain of jszhang@kernel.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=jszhang@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1704165923; a=rsa-sha256; cv=none; b=AcSgQUd3HX+ttF8hik9g3Wf59sltpylSnD18Iu9WfvJgaNYB7hHO5fyzyGQDhMTcgAp+/R QLHlSZzj0cgfRSOBW+DvHf4XSKAHMcoLTpHIJ0cYQ/ZqrxygR95VyNPW8Fc48tkU6AT8tk pJmjrDkveUAdUnCkE7oMCwo8zdGE2dg= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b="eFpz/HwQ"; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf20.hostedemail.com: domain of jszhang@kernel.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=jszhang@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1704165923; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=lobofrDR1pj7DY9JXew8sLB5zfTcOvQHtVZdEfdVtXU=; b=6YWL4M6JvVJ/BRKoGUORHq+xnWLH51V/zgS4hvaou6Hmb82qR3rZaqv3XKLI1x5Vdgct4J 98sUX51v3RXPriYrqbKm8Bc7FONE8zVNOG3FYllisaDqJ+i270yV8IOVAg0WgJkjvxz8/I CWB9c2i8LCI5d5uwWAq/38l3Wm/+smk= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by ams.source.kernel.org (Postfix) with ESMTP id 90600B80B26; Tue, 2 Jan 2024 03:25:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9ABCFC433C7; Tue, 2 Jan 2024 03:25:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1704165920; bh=o/p87hu05uv8+RjO26XUTaEkNHmf3m3Fyaag4qcW8jc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eFpz/HwQpMqLwV8rzZWW11P6Dv8qkJCFf/jA3j9XCkL7/ypnfinGbNA8QHws0wBUj wgYpbC096foRDJI1zKTYJ+eFZJ23P+/seKkF0K4GTanOpPW4trwk21boCAcz7rH1jt W+GOyIlUPV6uRl7EeHQJKqaxDMweOKubhk89NArt78GqNR/QEireW4+2vfU/+/Gl8T 9h3MA9fZK4+f/aGVWSTsy+LklekVjKO/0rJ1AUq7faP+1ZbPJ/3BaPUo/CQakpck/2 ifxd8ipDb53P3TKakbMzxyGG51wiXE3sikJoFCMGAVs+LwB18YNYXyGG7z3wgoqls3 TENkP7y2dOl1Q== Date: Tue, 2 Jan 2024 11:12:32 +0800 From: Jisheng Zhang To: Alexandre Ghiti Cc: Will Deacon , "Aneesh Kumar K . V" , Andrew Morton , Nick Piggin , Peter Zijlstra , Catalin Marinas , Paul Walmsley , Palmer Dabbelt , Albert Ou , Arnd Bergmann , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH 2/2] riscv: tlb: avoid tlb flushing if fullmm == 1 Message-ID: References: <20231228084642.1765-1-jszhang@kernel.org> <20231228084642.1765-3-jszhang@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 3EFDA1C000F X-Stat-Signature: yagxjcxjkr15rekhu4ybx5994u1wrzcs X-HE-Tag: 1704165923-739878 X-HE-Meta: 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 TucamtYa mI1Ri2/TsJNGHvafFMHzNUyrYboxv9uE9Zu2FNa836g0eyoG6NP+LJ3snBx6P8ImtTOSuvoXX8CRZWxqJ6Y5HyT0OKC0c+qtR1arTE7miW7IXOB9Hqh+xk85G+w3wv6+0kCgXz8N6XHRKI5qbjk1CAxHtA+StvLTH9XzfQskcZhIKV1of3vzzbrUGNKJXrPOAefKOntMkMorhLdtHQTddF+9akX/A7wiTHPTYUeupIbqtj+lqxD2eZkGafQ== 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: List-Subscribe: List-Unsubscribe: On Sat, Dec 30, 2023 at 07:26:11PM +0100, Alexandre Ghiti wrote: > Hi Jisheng, Hi Alex, > > On 28/12/2023 09:46, Jisheng Zhang wrote: > > The mmu_gather code sets fullmm=1 when tearing down the entire address > > space for an mm_struct on exit or execve. So if the underlying platform > > supports ASID, the tlb flushing can be avoided because the ASID > > allocator will never re-allocate a dirty ASID. > > > > Use the performance of Process creation in unixbench on T-HEAD TH1520 > > platform is improved by about 4%. > > > > Signed-off-by: Jisheng Zhang > > --- > > arch/riscv/include/asm/tlb.h | 9 +++++++++ > > 1 file changed, 9 insertions(+) > > > > diff --git a/arch/riscv/include/asm/tlb.h b/arch/riscv/include/asm/tlb.h > > index 1eb5682b2af6..35f3c214332e 100644 > > --- a/arch/riscv/include/asm/tlb.h > > +++ b/arch/riscv/include/asm/tlb.h > > @@ -12,10 +12,19 @@ static void tlb_flush(struct mmu_gather *tlb); > > #define tlb_flush tlb_flush > > #include > > +#include > > static inline void tlb_flush(struct mmu_gather *tlb) > > { > > #ifdef CONFIG_MMU > > + /* > > + * If ASID is supported, the ASID allocator will either invalidate the > > + * ASID or mark it as used. So we can avoid TLB invalidation when > > + * pulling down a full mm. > > + */ > > > Given the number of bits are limited for the ASID, at some point we'll reuse > previously allocated ASID so the ASID allocator must make sure to invalidate > the entries when reusing an ASID: can you point where this is done? Per my understanding of the code, the path would be set_mm_asid() __new_context() __flush_context() // set context_tlb_flush_pending if (need_flush_tlb) local_flush_tlb_all() Thanks > > > + if (static_branch_likely(&use_asid_allocator) && tlb->fullmm) > > + return; > > + > > if (tlb->fullmm || tlb->need_flush_all) > > flush_tlb_mm(tlb->mm); > > else