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 CA763C7EE22 for ; Fri, 28 Apr 2023 16:03:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229662AbjD1QDn (ORCPT ); Fri, 28 Apr 2023 12:03:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230478AbjD1QDl (ORCPT ); Fri, 28 Apr 2023 12:03:41 -0400 Received: from mail-yw1-x112e.google.com (mail-yw1-x112e.google.com [IPv6:2607:f8b0:4864:20::112e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 734802D51 for ; Fri, 28 Apr 2023 09:03:40 -0700 (PDT) Received: by mail-yw1-x112e.google.com with SMTP id 00721157ae682-552a6357d02so331927b3.3 for ; Fri, 28 Apr 2023 09:03:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1682697819; x=1685289819; 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=8QgP7oOPrCOMv4LzWX+EiazStwQFUH2wo4nGqGDOHAQ=; b=nvfKOytggc0TV2KC1oVi0eO9jK45GWpComHTEdKXS38DLXUAecZItgJp+zOL9O7ixs KRj5Ar99YcAM3NoA9WfWL63497jD7/7bITxxlATu2hbqRcj0JLhiIICwEqXHI9FdaL2I lqP/EXLTekjFh/xxnxZxYmQXbrVl7xQxOAYWqd7eDG6ntWNahsHR18+td5mj1D2fgUfy /jXGx1oPlomoWllZH4MNfPjphGCRMcOupm3Y5Vx1HkOVnOfDi96Q6zYOqkq0aUIhXwPc Ky0BAvwBDzrztRJ1E/wFcPq/b8C8sK9ibvtRYh138C4vdgydQ5E/HdfEsHec5NyAGESN IX+w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1682697819; x=1685289819; 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=8QgP7oOPrCOMv4LzWX+EiazStwQFUH2wo4nGqGDOHAQ=; b=h0q45+xoUbifxBJ7V2QGbnLW+dvJU1stfmBzF5atyD0Vt4o6xbaYCTUKR8oeVFjxkY nbiT9iVo6dKQ07KkyQh3tgsPj+06GEb/1vEIJZy0ZZYCHVrcXd6vXRUuVG4FFlXjRG8M uxqwjAgjTPt+xOSNwWpbQLokSt6aGXUjB/avb0iQihzwrvHWNXcylDkiJQ9Bwa4Lw1M+ wb0aRQDuCip+6/d+mAhW0zKrq0fB8K5lfLaxm7fFb5OjRVK+wBlEqBA+ubaETrSPalbt BfVkKYwrWZKE+mkcv6Xd3qyxwuuzkJyotZy9jnnjBtcsu3IfTidehDWYFg/gmDsXZAWc OGpQ== X-Gm-Message-State: AC+VfDxf4mZ4/OZN6mijj+DIKwH8YuUJrQ57OL1637cRjUCaSTEaRVCq k2/JOyRDErAZUoDpXa/D64obsi5c+CLdk39GqsFYXQ== X-Google-Smtp-Source: ACHHUZ64tMS0gUi6CNL1GsL8dHEGzJsUS2Ahoys8Q+1dLz3B4rmbWKE4ji0jyrWetULT4u121cXCnOjs+4mItf3RNCA= X-Received: by 2002:a81:6087:0:b0:54f:bb49:c3a2 with SMTP id u129-20020a816087000000b0054fbb49c3a2mr3750188ywb.28.1682697819401; Fri, 28 Apr 2023 09:03:39 -0700 (PDT) MIME-Version: 1.0 References: <20230427153345.451d86681f9c6775ea579e5a@linux-foundation.org> In-Reply-To: From: Suren Baghdasaryan Date: Fri, 28 Apr 2023 09:03:27 -0700 Message-ID: Subject: Re: [GIT PULL] MM updates for 6.4-rc1 To: Linus Torvalds Cc: Andrew Morton , mm-commits@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Lorenzo Stoakes , Vlastimil Babka Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 27, 2023 at 8:03=E2=80=AFPM Linus Torvalds wrote: > > On Thu, Apr 27, 2023 at 3:33=E2=80=AFPM Andrew Morton wrote: > > > > - Suren Baghdasaryan has improved mmap_lock scalability by switching to > > per-VMA locking. > > .. related to this, we have that new PER_VMA_LOCK_STATS config entry, > which is 'default y' and has basically no help test. > > Please don't do that. > > I don't think any of the VM debugging stuff should likely be 'default > y' in the first place, but if they are, they should most definitely > have a good *explanation* for why they should be on for a normal user. Understood. I wanted these stats enabled by default to be able to identify possible pathological cases and to also let users disable them if they can't tolerate even a small overhead in the pagefault path. Should I document this reasoning for the config option? > > Linus