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 0449B1C860C; Tue, 14 Jul 2026 13:22:10 +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=1784035332; cv=none; b=JyCplNqF+s0ndPQHSWWp7VSAhvNNfgwenPAXOqA/JC3NSbmR8xalcuN2zm/j/1gKJ4z5ySt5pINzbBG6kkuwXJ4d1kuU5P/xFBn/cCQXYq1NL80qrvYhOuEaGvdUMmSUQHTJSuZFE1dMutKTbT9NM8PbhlyiAdrF19R+TE2JGQ4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784035332; c=relaxed/simple; bh=Xj6legA3KHKMkiNyygSe0EFG22Cup3aZuOSMSCPRPkE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=muAKdBKE1rYe6nDl00c70UKLV3H9mfjW30ggHlhn/9kuRitk6sbni3A/P5HqqvXPX9N91NxOCligdm8Ic+mLddIJn5i6abyXpAkBZ8rwKGWoB16lYwndFIdabHRhVVw6Lb1rCaznDDJAyOrPCXFMJ1qC66v62Uy4MOuRkTHK3gQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hraK3PiX; 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="hraK3PiX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 509C91F000E9; Tue, 14 Jul 2026 13:22:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784035330; bh=GzusWZQvSdAC75BhLePWkECb62a3t8QA9yY4IsEwwDM=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=hraK3PiXKmtnhhb9PCsQZZMi0fnPEajxrk/hTrFivKeDnfGKVGMpZZ6CugQFEzU94 xqWjX8Vb5ll8Nfl0tUO/uqtwp43W6aVdY0JwSDoelJUSkdckhXmXJz2fOjCoRYIt8V T6igIIICawbRUXs4M8kFRb5DRJmS1bBe2BHAKBor0Voz19RQBbn+Rzj9UPE9wD6bWw Az4uP5At9Iau4mQvIX8Zx6i8qVHPikHKAAGyrkKbv7KrgcPQcIICv1RRFnkjKmh+4B 2UBgePb7962aGd5n+lHIssD10B4z90mlH87treQSZZIkFi1y+LOdv/2dP0udPrh1Hk I66RIsT/6WsNg== Message-ID: <9e9345c8-30a4-4f78-ba55-d7fa073b82d5@kernel.org> Date: Tue, 14 Jul 2026 15:22:06 +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 To: "Vlastimil Babka (SUSE)" , 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> <037d58c6-de55-4b69-bb71-905e03985657@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/14/26 15:09, Vlastimil Babka (SUSE) wrote: > 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. Right, it's a placeholder for "there is no migrate reason because it is unset" > So I think the name is more descriptive this way. Not sure I agree. The usual translation of -1 -> unset is NONE or UNSET. At least I was confused by "NEVER". -- Cheers, David