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[209.85.220.41]) by mx.google.com with SMTPS id x15sor3798460uan.25.2019.05.22.09.01.45 for (Google Transport Security); Wed, 22 May 2019 09:01:45 -0700 (PDT) Received-SPF: pass (google.com: domain of dancol@google.com designates 209.85.220.41 as permitted sender) client-ip=209.85.220.41; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=scYBgQFy; spf=pass (google.com: domain of dancol@google.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=dancol@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=RSdosCg7CAf5I4ACWla5jsLhMewb72YTSpe4zJkcCao=; b=scYBgQFym9ROAnpR66sReozWPRXNqJVUFlss1Ng44ycb9HpxOlw8L7UQ1Va7t73uvb DFN4rwIbWJsovtJ2lO1jCcCjsv/llpFZh7teYPx3c/Yc+JplddZXqxpVfZbwzI5Xn/LU 9roGRSVSkxgW4wDuxlB1LMucxNvX0+5VadelX4+ew/Ov8rX4CgCIijza9KX9Fco3/Nm2 8SL7c5IzGLvFUIvWKZDylrdng3FZ1T4GjMPVuy0qw+C2IfwG28lOU6P6EUI6IMf2Wcqr rEI5XiismRDtzA7X6wixbeBYQUnhz83yCAmnWShusLcB2rHnAQpp3dkFTdpQFJWPHfmz Odiw== X-Google-Smtp-Source: APXvYqxi2BZoiCj8jAFjAAZIHHrwShReaS6FEKzT0Pw5Kh4Zsg7Q1dxxKPve5INSlH18g3XyBmOg6fU4xTfpOx2B+bU= X-Received: by 2002:ab0:1051:: with SMTP id g17mr10254083uab.41.1558540905237; Wed, 22 May 2019 09:01:45 -0700 (PDT) MIME-Version: 1.0 References: <20190521110552.GG219653@google.com> <20190521113029.76iopljdicymghvq@brauner.io> <20190521113911.2rypoh7uniuri2bj@brauner.io> <20190522145216.jkimuudoxi6pder2@brauner.io> <20190522154823.hu77qbjho5weado5@brauner.io> <20190522160108.l5i7t4lkfy3tyx3z@brauner.io> In-Reply-To: <20190522160108.l5i7t4lkfy3tyx3z@brauner.io> From: Daniel Colascione Date: Wed, 22 May 2019 09:01:33 -0700 Message-ID: Subject: Re: [RFC 0/7] introduce memory hinting API for external process To: Christian Brauner Cc: Minchan Kim , Andrew Morton , LKML , linux-mm , Michal Hocko , Johannes Weiner , Tim Murray , Joel Fernandes , Suren Baghdasaryan , Shakeel Butt , Sonny Rao , Brian Geffon , Jann Horn Content-Type: text/plain; charset="UTF-8" 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 Wed, May 22, 2019 at 9:01 AM Christian Brauner wrote: > > On Wed, May 22, 2019 at 08:57:47AM -0700, Daniel Colascione wrote: > > On Wed, May 22, 2019 at 8:48 AM Christian Brauner wrote: > > > > > > On Wed, May 22, 2019 at 08:17:23AM -0700, Daniel Colascione wrote: > > > > On Wed, May 22, 2019 at 7:52 AM Christian Brauner wrote: > > > > > I'm not going to go into yet another long argument. I prefer pidfd_*. > > > > > > > > Ok. We're each allowed our opinion. > > > > > > > > > It's tied to the api, transparent for userspace, and disambiguates it > > > > > from process_vm_{read,write}v that both take a pid_t. > > > > > > > > Speaking of process_vm_readv and process_vm_writev: both have a > > > > currently-unused flags argument. Both should grow a flag that tells > > > > them to interpret the pid argument as a pidfd. Or do you support > > > > adding pidfd_vm_readv and pidfd_vm_writev system calls? If not, why > > > > should process_madvise be called pidfd_madvise while process_vm_readv > > > > isn't called pidfd_vm_readv? > > > > > > Actually, you should then do the same with process_madvise() and give it > > > a flag for that too if that's not too crazy. > > > > I don't know what you mean. My gut feeling is that for the sake of > > consistency, process_madvise, process_vm_readv, and process_vm_writev > > should all accept a first argument interpreted as either a numeric PID > > or a pidfd depending on a flag --- ideally the same flag. Is that what > > you have in mind? > > Yes. For the sake of consistency they should probably all default to > interpret as pid and if say PROCESS_{VM_}PIDFD is passed as flag > interpret as pidfd. Sounds good to me!