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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D3419C38A02 for ; Sun, 30 Oct 2022 00:54:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229476AbiJ3Ayu (ORCPT ); Sat, 29 Oct 2022 20:54:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229489AbiJ3Ayu (ORCPT ); Sat, 29 Oct 2022 20:54:50 -0400 Received: from mail-pj1-x1036.google.com (mail-pj1-x1036.google.com [IPv6:2607:f8b0:4864:20::1036]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5FD2FF02D; Sat, 29 Oct 2022 17:54:48 -0700 (PDT) Received: by mail-pj1-x1036.google.com with SMTP id m2so7638598pjr.3; Sat, 29 Oct 2022 17:54:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=to:references:message-id:content-transfer-encoding:cc:date :in-reply-to:from:subject:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=77q2Cu689tqGNFEGpDkfXqQD5HzMzl1ec5TJSSyQvvA=; b=EraN1j/tCpQDZrJ6/ChafeAePu1N6xwqHXnZgFGM2HTEcIYNsfqapOIp9JhcE6f2MJ fwQ8agRAzxeFH4TVG9SmI6vdBwOxt5w2zQOv+rsPY8aSdVl9EZVB/cDI8dUNO5i7/x9Y 3uA46NZDyAheIe66Z1sHl9VpS6CGbAZqyWo+eZXtcD/mU8L1LDy6fmXgWW8n3cghu/42 AB6kHTo9MNr/ftT8kwMwm4iKNGnvwzspTd+3RoF7WGydt2++63Z64GvHrIZLgiHUBMWa Rw2xo4PXQUsHAEf6y8yjgsm6++4OHrAIT/gwr7WzQRTXOBGOantv8cf04VGJAIo8Kccc 8HRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=to:references:message-id:content-transfer-encoding:cc:date :in-reply-to:from:subject:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=77q2Cu689tqGNFEGpDkfXqQD5HzMzl1ec5TJSSyQvvA=; b=MnQs/TcoVelGZSgIYmQwZnkUxWIps251q+ORQcJo+iMGWGJMYr+5H01WHxzH//nRcA DY0wlKOrs7PC9+P/lVcpgmeue1vSTl2wJ83ReUY2gXkN9JERi8NG3VZEh+jwUSNCChyK EBR0qJZ7lTQOaHSL7NLTTrVBEai+VJj9kmp0qUNZXZ4A+PL3WoXg+xPRrRrxHw7f7BDz iTMQ2Eb9t7d+5GTJtAelE67pBSHOmBgfFsyUYdW7siV/tocNJAWZvoGOzVNBSFiBkIt9 E+uTlNl9Ns8FpPNM0rvHiVFjmQeWjDRcjhws2y9Y7En55x7CeVhzQZCLUG2lTue2kKze KHlA== X-Gm-Message-State: ACrzQf1A3iJMe2g24+B3lEZV8Uy8qIB1YrIYgt0e+UTmRF0uHnhWRm2Y MuZmIRs6lvt2u8FTrtK0QbY= X-Google-Smtp-Source: AMsMyM6gu09eo3bvtudODSKlspE707KvxJBRdAPtM3xEOdPcKEWu5D0PrHM4NTTxtQHInt1uCrtMgQ== X-Received: by 2002:a17:902:bcc4:b0:181:899a:ac9c with SMTP id o4-20020a170902bcc400b00181899aac9cmr6914467pls.124.1667091287610; Sat, 29 Oct 2022 17:54:47 -0700 (PDT) Received: from smtpclient.apple (c-24-6-216-183.hsd1.ca.comcast.net. [24.6.216.183]) by smtp.gmail.com with ESMTPSA id 6-20020a631446000000b0046f7e1ca434sm1594012pgu.0.2022.10.29.17.54.45 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sat, 29 Oct 2022 17:54:46 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.120.41.1.1\)) Subject: Re: [PATCH v2] hugetlb: don't delete vma_lock in hugetlb MADV_DONTNEED processing From: Nadav Amit In-Reply-To: Date: Sat, 29 Oct 2022 17:54:44 -0700 Cc: Peter Xu , Linux-MM , kernel list , Naoya Horiguchi , David Hildenbrand , Axel Rasmussen , Mina Almasry , Rik van Riel , Vlastimil Babka , Matthew Wilcox , Andrew Morton , Wei Chen , stable@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: <7048D2B5-5FA5-4F72-8FDC-A02411CFD71D@gmail.com> References: <20221023025047.470646-1-mike.kravetz@oracle.com> To: Mike Kravetz X-Mailer: Apple Mail (2.3696.120.41.1.1) Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Oct 29, 2022, at 5:15 PM, Mike Kravetz = wrote: > zap_page_range is a bit confusing. It appears that the passed range = can > span multiple vmas. Otherwise, there would be no do while loop. Yet, = there > is only one mmu_notifier_range_init call specifying the passed vma. >=20 > It appears all callers pass a range entirely within a single vma. >=20 > The modifications above would work for a range within a single vma. = However, > things would be more complicated if the range can indeed span multiple = vmas. > For multiple vmas, we would need to check the first and last vmas for > pmd sharing. >=20 > Anyone know more about this seeming confusing behavior? Perhaps, = range > spanning multiple vmas was left over earlier code? I don=E2=80=99t have personal knowledge, but I noticed that it does not = make much sense, at least for MADV_DONTNEED. I tried to batch the TLB flushes = across VMAs for madvise=E2=80=99s. [1] Need to get to it sometime. [1] = https://lore.kernel.org/lkml/20210926161259.238054-7-namit@vmware.com/