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 6FDB5C2BD09 for ; Mon, 1 Jul 2024 21:28:12 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E96086B0088; Mon, 1 Jul 2024 17:28:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E46126B008A; Mon, 1 Jul 2024 17:28:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D0E096B008C; Mon, 1 Jul 2024 17:28:11 -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 B2CC46B0088 for ; Mon, 1 Jul 2024 17:28:11 -0400 (EDT) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 56EE8C1DFD for ; Mon, 1 Jul 2024 21:28:11 +0000 (UTC) X-FDA: 82292471982.27.7B07A25 Received: from mail-vk1-f175.google.com (mail-vk1-f175.google.com [209.85.221.175]) by imf03.hostedemail.com (Postfix) with ESMTP id 942862000E for ; Mon, 1 Jul 2024 21:28:09 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=ej3WzN4c; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf03.hostedemail.com: domain of 21cnbao@gmail.com designates 209.85.221.175 as permitted sender) smtp.mailfrom=21cnbao@gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1719869271; a=rsa-sha256; cv=none; b=ulTkCATyiTe0iOxUcZ+0ZiKA7raUEO8jhn8eMkCULcAEQtYAQCn77BTQyVgXgR2gpXvKLO U/8fs9PjZQI4qlqKwfRM5jhK/BVd9ksHmKB3299SNvPe6heE7s9MBUsFUxuBVyeSYeh4Q0 52AnABRnKSxbbgVfl2JaGGhmc96ft4s= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=ej3WzN4c; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf03.hostedemail.com: domain of 21cnbao@gmail.com designates 209.85.221.175 as permitted sender) smtp.mailfrom=21cnbao@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1719869271; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Ou1KHLdWw83FJUJksFOCwGjxghpAWqEzTlvLRzDw3ic=; b=4CyzWu+8Xs/gBkywAAVMQhbBTo/rQk+XKFt0gs1N020gu9uHG5TxqDoBaWGQ5FwpS7dP1q FwXBzePHsTBQPfml3OtPjDeniQTUH2kkXHHN05HhQ1CsXjU4eSoSPtM3sMAyPi4NtAMTey ELvJzyJlE22x7JsB03pJpxtcZZeNIQ8= Received: by mail-vk1-f175.google.com with SMTP id 71dfb90a1353d-4ef5a2f4e6cso1229874e0c.2 for ; Mon, 01 Jul 2024 14:28:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1719869288; x=1720474088; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=Ou1KHLdWw83FJUJksFOCwGjxghpAWqEzTlvLRzDw3ic=; b=ej3WzN4cKVZe58pR8vMlvsjziexBtvDnF2zk8lNwpHsw9oZnDVQsh1eBrYi7rudg+u k0ROogpddnRdm7kkoV2vrn+VtficD57aFUIbx0x03JHvimJ0pmDqRZBL9L+8DcPIIGj8 LslTQhbHfeigNQC0Hb8q9uDof1E4ma8RWV7jjPI549Xv2cFvcClRAmtn2E0NJe7F0xGv Aq+oFhKCq7ECESKYkUPZXfEYP2zvzu+/yX/jnax3N1ksnvp/tNaNt9f1MOy51CFRqTDV FXPQSg9W3PSmNz9O/NfAV59hZc72ZjvoUhwc2uhFNXKwMUs5TgaRtCxxFbOQq6QgvBWj Wvgw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1719869288; x=1720474088; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Ou1KHLdWw83FJUJksFOCwGjxghpAWqEzTlvLRzDw3ic=; b=SJBp/NswPArpYqqUIof93Eed06Tei8tty1JI3rhS2er7niL/jGYkAEyDFe5YAxLrYo W0t9r3e/lxhqsOH6+4XtaNiz+mrc/Pjb84rgBWi8DWZQonCV3kS7F0PwIXYS2MM7EAbP 61qRdnZ2tzjyS8CVqVuLV3jaMtSm06537WTg2mFv4Hi/tond9EVKPIr+ZkAiyUVPtBJA vbgjRUcE3Wuy6qiJbiRwVKQB1dXDiop6YLJaflIme0JqhM/P9BR9/+rlrrFEYL/RQ4r8 dwL4aDGO/3bu7kVn6r+qXLXYFuLRQVfXtknknKm3t1pzQrxk4iNfwleEIXFn3idPiNIx XPsw== X-Forwarded-Encrypted: i=1; AJvYcCULDnN6SbDzaK8dE6mLe1Ncp3VW1q5zMtEMQXGQpjvBZ2//2SAlVoeKcTdUfRWzFYrC8TTDH5t5Oz6Gk9hloE2kr0k= X-Gm-Message-State: AOJu0YyyDY/S8CKA5C6uC5HVKX8LAOePSZO6WindzoJ5xhjDX6d2ZQO1 PH7fM8lagnXlfj2TNSnfhUkHZU3ooazxTqPhiGDM8Ls4T8x1VE928orXrrbbF2GRJIuDAze+5It R63pByTyopqg93dxHPJLHDP2gIMo= X-Google-Smtp-Source: AGHT+IHRKNpdUtDXUbVFR16WEQTMX/Oyl0mZEjn1zvveqOa0IVQ8vXLuwCXweryD3Pz7igwtOV65lxH2rkWSQjF62fw= X-Received: by 2002:a05:6122:3224:b0:4ef:27dc:7a9 with SMTP id 71dfb90a1353d-4f2a5318a94mr8154206e0c.0.1719869288585; Mon, 01 Jul 2024 14:28:08 -0700 (PDT) MIME-Version: 1.0 References: <20240629111010.230484-1-21cnbao@gmail.com> <20240629111010.230484-3-21cnbao@gmail.com> In-Reply-To: From: Barry Song <21cnbao@gmail.com> Date: Tue, 2 Jul 2024 09:27:57 +1200 Message-ID: Subject: Re: [PATCH RFC v4 2/2] mm: support large folios swapin as a whole for zRAM-like swapfile To: Yosry Ahmed Cc: akpm@linux-foundation.org, linux-mm@kvack.org, chrisl@kernel.org, david@redhat.com, hannes@cmpxchg.org, kasong@tencent.com, linux-kernel@vger.kernel.org, mhocko@suse.com, nphamcs@gmail.com, ryan.roberts@arm.com, shy828301@gmail.com, surenb@google.com, kaleshsingh@google.com, hughd@google.com, v-songbaohua@oppo.com, willy@infradead.org, xiang@kernel.org, ying.huang@intel.com, baolin.wang@linux.alibaba.com, shakeel.butt@linux.dev, senozhatsky@chromium.org, minchan@kernel.org, Chuanhua Han Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 942862000E X-Stat-Signature: e4o1yjd41895fqhdffh7rbxhre733xi4 X-Rspam-User: X-HE-Tag: 1719869289-252513 X-HE-Meta: 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 fr0Czre9 08kjjaD4K6lSyVMjzJc1xRzLzDhx5+vMZTbgW71uhE44Vs75++ZxJr/KpqT7j4/qo2P/7N0k8cSHxuehQkRlggBSQD2LssstyLwHOJdZH99QI2LoTwzpHfm1VhJcjZ6yjnm1vem+xGc+2c8K97mjQCA12Z339utKYYCpbeo9UWz8rfP1bUWumOG9RNPwa3guGmC6HonqDsKEUX2HSQk+SSdf/xW4gARqElhsD8NX/8olQfVVLZ6GAvlQozOK8xxGpW2opfrUpyDrnOPru7QSD/2mMVA== 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 Tue, Jul 2, 2024 at 1:53=E2=80=AFAM Yosry Ahmed = wrote: > > [..] > > +static struct folio *alloc_swap_folio(struct vm_fault *vmf) > > +{ > > + struct vm_area_struct *vma =3D vmf->vma; > > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > > + unsigned long orders; > > + struct folio *folio; > > + unsigned long addr; > > + spinlock_t *ptl; > > + pte_t *pte; > > + gfp_t gfp; > > + int order; > > + > > + /* > > + * If uffd is active for the vma we need per-page fault fidelit= y to > > + * maintain the uffd semantics. > > + */ > > + if (unlikely(userfaultfd_armed(vma))) > > + goto fallback; > > + > > + /* > > + * a large folio being swapped-in could be partially in > > + * zswap and partially in swap devices, zswap doesn't > > + * support large folios yet, we might get corrupted > > + * zero-filled data by reading all subpages from swap > > + * devices while some of them are actually in zswap > > + */ > > If we read all subpages from swap devices while some of them are > actually in zswap, the corrupted data won't be zero-filled AFAICT, it > could be anything (old swapped out data). There are also more ways > this can go wrong: if the first page is in zswap, we will only fill > the first page and leave the rest of the folio uninitialized. > > How about a more generic comment? Perhaps something like: > > A large swapped out folio could be partially or fully in zswap. We > lack handling for such cases, so fallback to swapping in order-0 > folio. looks good to me, thanks! > > > + if (!zswap_never_enabled()) > > + goto fallback; > > +