From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B8866448D1F; Tue, 14 Jul 2026 13:09:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784034572; cv=none; b=iW5YzhZMJMAZID5TN/+NBE95rBweOi2t5PUCFDWYgbgxRF92tUr6ngeRZMFAeNy9k+nzUYZJK9HNb5RCaAFeuSFfKDXm37ILmn4A7Scgb3DuYK9fZr7uyjQTZXaFWLtubPNV+9Lr9JbQT82bHhX1xm9gvvHnn6dipMjjXA1AgO4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784034572; c=relaxed/simple; bh=PtWpq51zL8SCuSo8Qjje4u24kXZ9DAI+ry5vr8Wp3XI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Kg+stOEHqrVLBhf9qAjxyuUppsH0yjA9UeGCtwsCddTPdrXP+Eph06/N7NCFLEUsRNUx66CpgI9lNej+9VVlsuiuReQLiBP5+k7NNCGYFsIKVeCN5VWH1/kacRDTM0h0o3qjaMdmv6NE772L5e8hz35imuqFuF7im6/woz8M9+Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dpRJoLzw; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dpRJoLzw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 29B171F000E9; Tue, 14 Jul 2026 13:09:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784034571; bh=kuU7fP5JxANN4DJ9eHGNnkUQXlno2tJDQn4DVBGprns=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=dpRJoLzwZiGcUmL6g/gynlg3FDZmRkf9wZ079mK6qsQlHk4J4q4EbzA/9expriTFc z50SZVFrYDmBd8SHH7a+CO7C3Nab3+2gTGPsMHOAakKTFlFIZS76gA6rxFGDLLIDDC Na//Tc8iXHj3bkqxrXz0/0R4eT/lKmCGE3DENgoEWq60JYtw8J1oZu4Lh8TD9GkfCj bZhkXbF4XhnuK4QZHa6I2sFQ3K3nOmaHKL62Kt+mpbhyturS7KpEG2RPQl333dv4E+ n3F9hbKeZEh+zoaW7Ap02LPRs+uSiRTgrW9TDkdIEnPyAEWCixkIvVLNPvTFzPCoZA qF6RcIJIKV0uA== Message-ID: <037d58c6-de55-4b69-bb71-905e03985657@kernel.org> Date: Tue, 14 Jul 2026 15:09:25 +0200 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 2/9] mm/page_owner: add MR_NEVER to enum migrate_reason and use it for last_migrate_reason Content-Language: en-US To: "David Hildenbrand (Arm)" , Ye Liu , Andrew Morton , Steven Rostedt , Masami Hiramatsu , Jan Kiszka , Kieran Bingham Cc: Zi Yan , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Mathieu Desnoyers , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org References: <20260714015117.78351-1-ye.liu@linux.dev> <20260714015117.78351-3-ye.liu@linux.dev> <9e0db1c2-06ca-4dba-8fb1-552fab91cb02@kernel.org> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/14/26 15:05, David Hildenbrand (Arm) wrote: > On 7/14/26 03:51, Ye Liu wrote: >> The last_migrate_reason field uses -1 as a sentinel value to mean "no >> migration has happened". Replace the four bare -1 occurrences by >> adding a proper MR_NEVER member to enum migrate_reason, defining a >> corresponding "never_migrated" string in the MIGRATE_REASON trace >> macro, and updating the GDB page_owner script to use MR_NEVER instead >> of the hardcoded -1 so that lx-dump-page-owner does not incorrectly >> report unmigrated pages as migrated. >> >> No functional change. >> >> Signed-off-by: Ye Liu >> Reviewed-by: Zi Yan >> Reviewed-by: Vlastimil Babka (SUSE) >> --- >> include/linux/migrate_mode.h | 1 + >> include/trace/events/migrate.h | 3 ++- >> mm/page_owner.c | 8 ++++---- >> scripts/gdb/linux/page_owner.py | 4 +++- >> 4 files changed, 10 insertions(+), 6 deletions(-) >> >> diff --git a/include/linux/migrate_mode.h b/include/linux/migrate_mode.h >> index 265c4328b36a..05102d4d2490 100644 >> --- a/include/linux/migrate_mode.h >> +++ b/include/linux/migrate_mode.h >> @@ -25,6 +25,7 @@ enum migrate_reason { >> MR_LONGTERM_PIN, >> MR_DEMOTION, >> MR_DAMON, >> + MR_NEVER, /* page has never been migrated */ > > Shouldn't this be more like > > "MR_NONE" ? > > As "never" is not really a "reason" ? It's not used ever as a reason that would be actually passed to migration. So I think the name is more descriptive this way.