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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C2840C433FE for ; Mon, 30 May 2022 15:53:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=FLSRw1Jy++u138uHmR+3/vsNjIJLD69ZFMJsI3B6u+8=; b=YblrE10HFRvBhU 8TZaFFOq3SGIioV0VAIzeuVV1E40a1IDloa+T5lT+HZw1wrV3rViN9OHgooRhLMeJqgRejoRWPhgU GutQAurfpSXmNhD6ynMJ/dU/pDIhrgQINScS0A2DZslsX0shEt2ZZnzN+UnUzZSkLCGkej1M1IXqV RQ8zjMDdmCYkmilMSfv0miLfhXeQrDCLldVQgYLLl9S00d/muWkj9QKxg9DRXeKtT6kHAeQvdxy7P oTswHaDQDHKDgmoBNA2z3Kb7KIZBav0Sm8a1pSxSWFzPatstfM+/WQxPDRhy2jJ30/d9dUIVqneTE Cfedp/kt79o0GF4MPdKw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nvhhe-007Z7m-5V; Mon, 30 May 2022 15:53:10 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nvhhZ-007Z2r-BO for linux-riscv@lists.infradead.org; Mon, 30 May 2022 15:53:07 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1653925984; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=bDYue/Afd3VGZHzU7tYF7qy5xBeBUpqe85rLuoAiRcE=; b=YgN3kgKJ0UzknAvHl1zBxccmG3i56sV4QgvUX4eJf0Ld94UI/B3rzQ+H9H9r71ucRytUDE 7td1PYJ+GkbJCAOJz8RObrIYqARuP487sIlHwkitK2SZiJRk2NlllsX+0KBKmdVkbl9XRx SSAPhGUN1SgEKW0W6OTaMjFD1JgioAg= Received: from mail-io1-f69.google.com (mail-io1-f69.google.com [209.85.166.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-647-ySAo21r4NCO45E4MPq8UVA-1; Mon, 30 May 2022 11:53:01 -0400 X-MC-Unique: ySAo21r4NCO45E4MPq8UVA-1 Received: by mail-io1-f69.google.com with SMTP id l67-20020a6b3e46000000b00660b8c61a31so5682839ioa.0 for ; Mon, 30 May 2022 08:53:01 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=bDYue/Afd3VGZHzU7tYF7qy5xBeBUpqe85rLuoAiRcE=; b=UCnq0Uc51eCYOPoIW1QhnsaR/eGRhxU/dWiO4aM4NExT60bhFmgmx3B999FMt9aMJN uYXmb04uD2GVLUpTaviUX4VWD2gHU8ddxlC7KwBb1uhn3EqYheUXnBU7Hm5ZQp/Afmnf EJ3MfKOzKgn9QaKyiY0tNPfpj8Cs3Mr4aYGmvAZZP8o5UowOG6eNOs/JtPbhywA7wYE+ upWKbwH0ffwkRCoQxi+u3pJVbgSoQgbnFqFx101dwMs4kYor6iAnpxzVCiRLHG8GtYyC HLfwRU7GJN7aKRXbwEm+KM5PZ+86cswl2VMBDJoJepiTkjk4rDRZzRlSyEXCwrn6HB8t fzMg== X-Gm-Message-State: AOAM531dmLk0acV1h5k304vniEgX7l1MEkXz4WKgfQTIDR3IGnRrQ2s0 W5hBRTDVdpebmYUWRH1G1N4UEMAzSFb8OekW+4zBvt6cO/qJFyyxhWJLt2JtdAFSjDYqT1UJf19 EWAQzp0pVPepdLeWJiC7yv/rk7ait X-Received: by 2002:a5d:9cc8:0:b0:663:2899:4b8 with SMTP id w8-20020a5d9cc8000000b00663289904b8mr16857397iow.192.1653925980597; Mon, 30 May 2022 08:53:00 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyKQIoyyqGc41UCjMUnObS0GZ5Lh8IPSVLY8KDGIOa5YRMfMwdzANPXLWIG/1E7oUnwvcvO1w== X-Received: by 2002:a5d:9cc8:0:b0:663:2899:4b8 with SMTP id w8-20020a5d9cc8000000b00663289904b8mr16857337iow.192.1653925980357; Mon, 30 May 2022 08:53:00 -0700 (PDT) Received: from xz-m1.local (cpec09435e3e0ee-cmc09435e3e0ec.cpe.net.cable.rogers.com. [99.241.198.116]) by smtp.gmail.com with ESMTPSA id 66-20020a021d45000000b0032e75bfe344sm2781109jaj.171.2022.05.30.08.52.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 May 2022 08:52:59 -0700 (PDT) Date: Mon, 30 May 2022 11:52:54 -0400 From: Peter Xu To: Christian Borntraeger Cc: Heiko Carstens , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Will Deacon , Matt Turner , linux-s390@vger.kernel.org, Andrew Morton , Brian Cain , Borislav Petkov , linux-alpha@vger.kernel.org, Alistair Popple , Jonas Bonn , linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, Michael Ellerman , Stefan Kristiansson , linux-snps-arc@lists.infradead.org, Vineet Gupta , Vasily Gorbik , Vlastimil Babka , Ivan Kokshaysky , Rich Felker , sparclinux@vger.kernel.org, Russell King , David Hildenbrand , Benjamin Herrenschmidt , Nicholas Piggin , "James E . J . Bottomley" , linux-xtensa@linux-xtensa.org, linux-sh@vger.kernel.org, Paul Walmsley , linux-m68k@lists.linux-m68k.org, linuxppc-dev@lists.ozlabs.org, Richard Henderson , Guo Ren , linux-parisc@vger.kernel.org, Andrea Arcangeli , Helge Deller , Al Viro , Albert Ou , linux-um@lists.infradead.org, "H . Peter Anvin" , Janosch Frank , Sven Schnelle , Anton Ivanov , openrisc@lists.librecores.org, Thomas Bogendoerfer , linux-hexagon@vger.kernel.org, Andy Lutomirski , Stafford Horne , linux-csky@vger.kernel.org, Thomas Gleixner , linux-mips@vger.kernel.org, Paul Mackerras , Alexander Gordeev , Dinh Nguyen , Palmer Dabbelt , "David S . Miller" , Johannes Weiner , Hugh Dickins , Ingo Molnar , Peter Zijlstra , linux-riscv@lists.infradead.org, Max Filippov , Catalin Marinas , Geert Uytterhoeven , Johannes Berg , Chris Zankel , Michal Simek , x86@kernel.org, Yoshinori Sato , Dave Hansen , Richard Weinberger , Ingo Molnar Subject: Re: [PATCH v4] mm: Avoid unnecessary page fault retires on shared memory types Message-ID: References: <20220527193936.30678-1-peterx@redhat.com> <33fd4731-9765-d78b-bdc3-f8243c98e81f@linux.ibm.com> MIME-Version: 1.0 In-Reply-To: <33fd4731-9765-d78b-bdc3-f8243c98e81f@linux.ibm.com> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=peterx@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220530_085305_812881_F9BE956B X-CRM114-Status: GOOD ( 20.65 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Mon, May 30, 2022 at 11:35:10AM +0200, Christian Borntraeger wrote: > > > Am 29.05.22 um 22:33 schrieb Heiko Carstens: > [...] > > > > Guess the patch below on top of your patch is what we want. > > Just for clarification: if gmap is not NULL then the process is a kvm > > process. So, depending on the workload, this optimization makes sense. > > > > diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c > > index 4608cc962ecf..e1d40ca341b7 100644 > > --- a/arch/s390/mm/fault.c > > +++ b/arch/s390/mm/fault.c > > @@ -436,12 +436,11 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) > > /* The fault is fully completed (including releasing mmap lock) */ > > if (fault & VM_FAULT_COMPLETED) { > > - /* > > - * Gmap will need the mmap lock again, so retake it. TODO: > > - * only conditionally take the lock when CONFIG_PGSTE set. > > - */ > > - mmap_read_lock(mm); > > - goto out_gmap; > > + if (gmap) { > > + mmap_read_lock(mm); > > + goto out_gmap; > > + } > > + goto out; > > Yes, that makes sense. With that > > Acked-by: Christian Borntraeger Looks sane, thanks Heiko, Christian. I'll cook another one. -- Peter Xu _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv