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Shutemov" To: Dave Hansen Cc: Dave Hansen , Andy Lutomirski , Peter Zijlstra , x86@kernel.org, Kostya Serebryany , Andrey Ryabinin , Andrey Konovalov , Alexander Potapenko , Taras Madan , Dmitry Vyukov , "H . J . Lu" , Andi Kleen , Rick Edgecombe , Bharata B Rao , Jacob Pan , Ashok Raj , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCHv10 09/15] x86: Expose untagging mask in /proc/$PID/arch_status Message-ID: <20221018222419.oy2z2wanvwp2pnrm@box.shutemov.name> References: <20221018113358.7833-1-kirill.shutemov@linux.intel.com> <20221018113358.7833-10-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1666131867; a=rsa-sha256; cv=none; b=c5NC/2wCISW9AwId9S7MGQhP5okj4TvednXJbkb6gQmDG4yMJLB+8TdwTLtYIz16a2GKBk JT+GYxLYcU0rQaN3Zi8qDFOkfbg9ybHOX1+06VIBvbWj9QHFabnWO9n0AENzvfkBChYmbY S0Vm+Kv2pVJ0C/EFvA54YY0/N8mI5Rs= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=C6jAa3Xc; spf=none (imf26.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 192.55.52.151) smtp.mailfrom=kirill.shutemov@linux.intel.com; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1666131867; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=vHXXYibUINwIgQR0oiJA5Nrm93TCSdVW+EvhjRUguyE=; b=JfZ0N0O5bSVavwrHzYCvlhJeGeDUqsukzQEMeN5g1AR0EocLNzPQCmiXx49IKcsdwSiXto Lsgwb3pLabHjAeTVOSFZOi/zAYc3yynHMIIVJyaSEjCcgIv73RieVqgR/MG65A1Pf4fAsy Xok/1XscjupV3U8e+x1MXEveuR+sXX0= X-Stat-Signature: hbb9euqkdsndmrw1jdkefgk5gb8so49g X-Rspamd-Queue-Id: E5B9F140034 X-Rspam-User: X-Rspamd-Server: rspam03 Authentication-Results: imf26.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=C6jAa3Xc; spf=none (imf26.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 192.55.52.151) smtp.mailfrom=kirill.shutemov@linux.intel.com; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none) X-HE-Tag: 1666131866-91692 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 Tue, Oct 18, 2022 at 02:02:43PM -0700, Dave Hansen wrote: > On 10/18/22 04:33, Kirill A. Shutemov wrote: > > Add a line in /proc/$PID/arch_status to report untag_mask. It can be > > used to find out LAM status of the process from the outside. It is > > useful for debuggers. > > Considering that address masking is not x86-specific, it seems like this > needs a better home (another file in /proc). In generic /proc/$PID/status? And I'm not sure if it is a good idea at this stage. Semantics around tags is not settled across architectures: somewhere it is per-thread, somewhere per-process, somewhere it is global. Maybe keep it arch-specific? > This could even be left out of the series for now, right? Nothing, > including the selftests, depends on it. GDB folks wanted to know the mask. -- Kiryl Shutsemau / Kirill A. Shutemov