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 3B1ECCCA47C for ; Tue, 7 Jun 2022 19:14:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A679F6B007E; Tue, 7 Jun 2022 15:14:29 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9F0DA8D0002; Tue, 7 Jun 2022 15:14:29 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 869866B0082; Tue, 7 Jun 2022 15:14:29 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 723846B007E for ; Tue, 7 Jun 2022 15:14:29 -0400 (EDT) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 491571338 for ; Tue, 7 Jun 2022 19:14:29 +0000 (UTC) X-FDA: 79552391058.16.D6666F6 Received: from mail-pl1-f180.google.com (mail-pl1-f180.google.com [209.85.214.180]) by imf02.hostedemail.com (Postfix) with ESMTP id 9AABC80057 for ; Tue, 7 Jun 2022 19:14:28 +0000 (UTC) Received: by mail-pl1-f180.google.com with SMTP id t2so15625468pld.4 for ; Tue, 07 Jun 2022 12:14:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=4gIoCqHZbpYfz/4CTgGuHK7roKtjg6cuYorUKPnysxI=; b=D/1axmuX0TjXZkgX/H+s6PRCcg/n/Uu3fEbHrZADgIe5vs90JvfL57nAfktz0s73ir 7Z1G8bOuIp/hM2WFqLIjRzCRpaO8RjBvfqJCt678E1E7BR63J7vhdi1fWCQFufWsPv/G PhKztNhxerDRKI4eYGU7gzzUw4cPWPYYSxptfzZevJeOR9GIaVxdDW4T8h/QO9pgeXKE AYtklMxkK4VYbF6nxuST0+l/ne8+bZwgOj+odITMMzWkk5wGZS0ZiGfbH5QhcyzxXRos 4VMhllMPOs4KzLudbOM4vBjC+dZ7N6+Mj7UoSVq2xL3QLKIhJzO49Rotp0hqH1utJ6+E etPA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=4gIoCqHZbpYfz/4CTgGuHK7roKtjg6cuYorUKPnysxI=; b=iwA0A2ZIcZsvIRbLuBl8aRgOomMqAm8Bq2pUNSHf/C92Lg8eORlZxVQvwmDvPEoMqF 5xAiJ6MISSNBH1tETBhN8dB/ZuleOJ5Z6NZRQOSCdEynIz1Av3ncEAmdr6iWqaFNP6j4 XrSMEC9TeHPFjhUg9pZ5zkp5hKWr+HwW4/E+tzI8tvXDPitBP6aH5qWsOnszze5dxRdW 3BeUnKtpSaJGnja6Fzj2HRwJfjlwkSHtXCEK63VCuhwLvxvQMi5MZ3LGQl+sLZOwc7SX 25/nDe3tSdqs/ZG2te9dsftngOPs4TjsE50qjNTLZNVJ/4nf3vW9kjb+XnYBQgjtxNQK fBiA== X-Gm-Message-State: AOAM533dJzJUDhVe9YjtufyWgGyWTbRDlZ2o+GbAhB6RHroJ2E6QM6tw HKEh+BGFQ91qK3Qs10HQT7iLDRx0Zp03LLhZfk0= X-Google-Smtp-Source: ABdhPJzeewsCIfohsl0IKhzm8qpSromrDRxrjMQbUbLveC0ElWX8fohgBMGM+zvTQN8IbjzeW4A+gVzf2Z5HKPz5hz4= X-Received: by 2002:a17:90b:4c4c:b0:1e8:6f9a:b642 with SMTP id np12-20020a17090b4c4c00b001e86f9ab642mr16072321pjb.21.1654629267665; Tue, 07 Jun 2022 12:14:27 -0700 (PDT) MIME-Version: 1.0 References: <20220604004004.954674-1-zokeefe@google.com> <20220604004004.954674-12-zokeefe@google.com> In-Reply-To: <20220604004004.954674-12-zokeefe@google.com> From: Yang Shi Date: Tue, 7 Jun 2022 12:14:15 -0700 Message-ID: Subject: Re: [PATCH v6 11/15] mm/madvise: add MADV_COLLAPSE to process_madvise() To: "Zach O'Keefe" Cc: Alex Shi , David Hildenbrand , David Rientjes , Matthew Wilcox , Michal Hocko , Pasha Tatashin , Peter Xu , Rongwei Wang , SeongJae Park , Song Liu , Vlastimil Babka , Zi Yan , Linux MM , Andrea Arcangeli , Andrew Morton , Arnd Bergmann , Axel Rasmussen , Chris Kennelly , Chris Zankel , Helge Deller , Hugh Dickins , Ivan Kokshaysky , "James E.J. Bottomley" , Jens Axboe , "Kirill A. Shutemov" , Matt Turner , Max Filippov , Miaohe Lin , Minchan Kim , Patrick Xia , Pavel Begunkov , Thomas Bogendoerfer Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: 5bzy5txzfuj38rpktrbyek5xaypc7yi1 Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b="D/1axmuX"; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf02.hostedemail.com: domain of shy828301@gmail.com designates 209.85.214.180 as permitted sender) smtp.mailfrom=shy828301@gmail.com X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 9AABC80057 X-HE-Tag: 1654629268-923241 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: On Fri, Jun 3, 2022 at 5:40 PM Zach O'Keefe wrote: > > Allow MADV_COLLAPSE behavior for process_madvise(2) if caller has > CAP_SYS_ADMIN or is requesting collapse of it's own memory. It is fine to me. But I'd like to hear more from other folks. > > This is useful for the development of userspace agents that seek to > optimize THP utilization system-wide by using userspace signals to > prioritize what memory is most deserving of being THP-backed. > > Signed-off-by: Zach O'Keefe > --- > mm/madvise.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/mm/madvise.c b/mm/madvise.c > index eccac2620226..b19e2f4b924c 100644 > --- a/mm/madvise.c > +++ b/mm/madvise.c > @@ -1171,13 +1171,15 @@ madvise_behavior_valid(int behavior) > } > > static bool > -process_madvise_behavior_valid(int behavior) > +process_madvise_behavior_valid(int behavior, struct task_struct *task) > { > switch (behavior) { > case MADV_COLD: > case MADV_PAGEOUT: > case MADV_WILLNEED: > return true; > + case MADV_COLLAPSE: > + return task == current || capable(CAP_SYS_ADMIN); > default: > return false; > } > @@ -1455,7 +1457,7 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec, > goto free_iov; > } > > - if (!process_madvise_behavior_valid(behavior)) { > + if (!process_madvise_behavior_valid(behavior, task)) { > ret = -EINVAL; > goto release_task; > } > -- > 2.36.1.255.ge46751e96f-goog >