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 X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD6C5C31E40 for ; Mon, 10 Jun 2019 14:47:18 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8B2832085A for ; Mon, 10 Jun 2019 14:47:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="X5g0JAvd" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8B2832085A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 270DD6B0269; Mon, 10 Jun 2019 10:47:18 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2224C6B026A; Mon, 10 Jun 2019 10:47:18 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1115E6B026B; Mon, 10 Jun 2019 10:47:18 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-pg1-f200.google.com (mail-pg1-f200.google.com [209.85.215.200]) by kanga.kvack.org (Postfix) with ESMTP id D0ABB6B0269 for ; Mon, 10 Jun 2019 10:47:17 -0400 (EDT) Received: by mail-pg1-f200.google.com with SMTP id j26so7042703pgj.6 for ; Mon, 10 Jun 2019 07:47:17 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:date:from:subject:to:cc :references:in-reply-to:mime-version:user-agent:message-id :content-transfer-encoding; bh=Wq53+njaY8Nizg87bnJv9I6awFz838NRdQghS0a7fkM=; b=HP8wO75lexD9W9s98lKDANcpW0NYU6jcC7k+o/rudlEjJVfQLEMQNXpw2e/uDlmscY mMEwh2D9/rvrsRpQ0d6ODjKrp+sjzneJdy6thipwhgfZyXK8Lnr6M6VhFoQjscqRdIAL RNzUhKIbf4cR2qHpEfeyVRcTkm2TO2yKZcRiiXhmCDKpOaHdLcjdU3jwNykqufo+Wljy Ae0ISgeNbgcoqzALdEX8I+46UyWnf9TspMpxSdZbmH2r3tmNRuIr9eeVRWKuxaKT3M9Y XWpTaj8IOZwe8nQaKvSdhg7PtXGX06msDvCi9Zxrwsid07Z1hAT8I/XQ/IyHb7tYUz9P AL4Q== X-Gm-Message-State: APjAAAUh5IY5OYY+kyZdEex2q77IKGSxZzD8w72MbBQJCCcQ/zz8ldox fKBA0IW28whOR2kzUfP4/aCGjSL9iXfkiIO2ExxoxDimrA7YEJDqXF7JD6k3tLRtnf7BHboUjyL DMFY+eWmw3lrP9QscfQfz82hLNTAv8iyLIZ1xnARAVqwJkMdr9a2nlIKneqXI/a1D6g== X-Received: by 2002:a63:1d1d:: with SMTP id d29mr5998384pgd.259.1560178037355; Mon, 10 Jun 2019 07:47:17 -0700 (PDT) X-Received: by 2002:a63:1d1d:: with SMTP id d29mr5998329pgd.259.1560178036369; Mon, 10 Jun 2019 07:47:16 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1560178036; cv=none; d=google.com; s=arc-20160816; b=qhly4ncPMk0f8DFGDj7MWMuGFQsTinZSbvS+b5tV3EDD0NdyE44ZkmUWqQ0hs81kBH HCNHzbeGkfSYZtU7FhNbn2MLBW1CsDhXcly0a2RJNBsWY0EuDAoyakwwFwMhWCtJeYCh 0YgsjWcN3g0kkK9/2gTGOYGCPH+dX9d4qja0quA49svKTswVUsQnuFbquO4UEvq4p8X+ UCc60Lt3QE2KK/kzMJb4lEKbpwKHZ6+yj82JsLbi2Tloid/e6y/1Nq1PX8MHfkW9oUqE rBb55734R3D8Dv0itKh0fopvjRbjG+5E0BiMeFwxMOcXT+M5O9y6mlo7qshqY9BtrATb pIog== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:message-id:user-agent:mime-version :in-reply-to:references:cc:to:subject:from:date:dkim-signature; bh=Wq53+njaY8Nizg87bnJv9I6awFz838NRdQghS0a7fkM=; b=AV/fZmcZ6gV36Ldip9pLaosqNkE5tC5QrTr4X/UvG89TmAZo4o9VlSDX/UNrfSO73m eeNE2BsN+eHtGdXpa2SmXztFR0voS6bI+TongzObUCkJd4yQywFXuCm2qUkKmGVlbi1X +JiEbTc1tMGcWc/hElsQWpXgsnS4TsCs3PWK0/GP6Yl57/CA1rI70hFRDUd/4/YVDwqU vs+TqRGxfmZnXxgIjkMGbbCOxhfeOeW+asgWVcXQw0OiCAC7QfKBP2hq4mY9BzpKhlMM +MvYG/yuLOcLbQ+HB/UvdJQzzFFyCWYXt6K2LrIoWIt5QO/5Yd7Iv9o30/Lwvjn1Gfbl NTWw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=X5g0JAvd; spf=pass (google.com: domain of npiggin@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=npiggin@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id 73sor11858747plf.60.2019.06.10.07.47.16 for (Google Transport Security); Mon, 10 Jun 2019 07:47:16 -0700 (PDT) Received-SPF: pass (google.com: domain of npiggin@gmail.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=X5g0JAvd; spf=pass (google.com: domain of npiggin@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=npiggin@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:subject:to:cc:references:in-reply-to:mime-version :user-agent:message-id:content-transfer-encoding; bh=Wq53+njaY8Nizg87bnJv9I6awFz838NRdQghS0a7fkM=; b=X5g0JAvdV1k6T8yY6ZUvrcraWM4yMrG/lxJCK+nAqRLcZyfzQtXY4ZbYz6fOYHWy3n Ou8dcJ4J6pIL1UEocGoC4sPgamfUWIHesWmZ8UX6rEWSdzt9ISIcx9cBiIgBO1pLSbDQ bhOBx/V93amqxNh29DiYEna/vlDWwPNSH0HP8kuGzL0W2dnDnjJk1o+mR2xDI146xllb CGKw3KHTmadPXuq8gLrXsXWVk8oNjiQOOuOZXkERDlgP23OsxNnnrUkyJ5sqo3VO0K3v NviZJEwFJwnWh80oqJu8/n12fYX46vxiYKwSmmxCyHZAabHAJNThB0WoxME22CohL67N 7IJQ== X-Google-Smtp-Source: APXvYqzO+K5a5izxxRmZJDOMMeEKbiwUXCm3sWfTX0ai2WfHFHXOFTxBzy4ayjR/yFM/5mp8uqkfJw== X-Received: by 2002:a17:902:8f81:: with SMTP id z1mr4934200plo.290.1560178036097; Mon, 10 Jun 2019 07:47:16 -0700 (PDT) Received: from localhost (60-241-56-246.tpgi.com.au. [60.241.56.246]) by smtp.gmail.com with ESMTPSA id p68sm4145337pfb.80.2019.06.10.07.47.14 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 10 Jun 2019 07:47:15 -0700 (PDT) Date: Tue, 11 Jun 2019 00:44:49 +1000 From: Nicholas Piggin Subject: Re: [PATCH 4/4] mm/vmalloc: Hugepage vmalloc mappings To: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org References: <20190610043838.27916-1-npiggin@gmail.com> <20190610043838.27916-4-npiggin@gmail.com> <20190610141036.GA16989@lakrids.cambridge.arm.com> In-Reply-To: <20190610141036.GA16989@lakrids.cambridge.arm.com> MIME-Version: 1.0 User-Agent: astroid/0.14.0 (https://github.com/astroidmail/astroid) Message-Id: <1560177786.t6c5cn5hw4.astroid@bobo.none> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable 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: Mark Rutland's on June 11, 2019 12:10 am: > Hi, >=20 > On Mon, Jun 10, 2019 at 02:38:38PM +1000, Nicholas Piggin wrote: >> For platforms that define HAVE_ARCH_HUGE_VMAP, have vmap allow vmalloc t= o >> allocate huge pages and map them >>=20 >> This brings dTLB misses for linux kernel tree `git diff` from 45,000 to >> 8,000 on a Kaby Lake KVM guest with 8MB dentry hash and mitigations=3Dof= f >> (performance is in the noise, under 1% difference, page tables are likel= y >> to be well cached for this workload). Similar numbers are seen on POWER9= . >=20 > Do you happen to know which vmalloc mappings these get used for in the > above case? Where do we see vmalloc mappings that large? Large module vmalloc could be subject to huge mappings. > I'm worried as to how this would interact with the set_memory_*() > functions, as on arm64 those can only operate on page-granular mappings. > Those may need fixing up to handle huge mappings; certainly if the above > is all for modules. Good point, that looks like it would break on arm64 at least. I'll work on it. We may have to make this opt in beyond HUGE_VMAP. Thanks, Nick =