From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mslow3.mail.gandi.net (mslow3.mail.gandi.net [217.70.178.249]) (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 9C88313B293 for ; Mon, 3 Nov 2025 14:15:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.178.249 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762179323; cv=none; b=Nnq7u9jEZoV4NFq6G6uibbx/W7j4sZK0xoaxLSmjeo26bPJVpC7EvLw6lsieOhHIurfBngX//yNU3O9/dLzWLy7iRmJ2AzFySz3dmlcLHiYtNXDHYwNMcVNwQPkvWspcM7piQj0v6Y+J9uOjeL6wNmmA9vYycTLjkn2ECifV5Xo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762179323; c=relaxed/simple; bh=Oj8TIcowaCPGB4I1KVwlM1xBTAbemXe8vYU27KXmWJU=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=ALERuAfgQA3slXAQBSEVmrq3QpNYt1WgB34T6P1LPEEieUybnPr7mZhWT2EpaECYGvUSskXiExbLlX108vX1Q5hWMa8ixa4bodQz9+exe+fKNsmfGrz+Hb+8yHLT3z14v2ucb7waBAIn9QYGknL2/aMsyqtpEoGVVNaJFyDDoEg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=xenomai.org; spf=pass smtp.mailfrom=xenomai.org; dkim=pass (2048-bit key) header.d=xenomai.org header.i=@xenomai.org header.b=grs2xKUa; arc=none smtp.client-ip=217.70.178.249 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=xenomai.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=xenomai.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=xenomai.org header.i=@xenomai.org header.b="grs2xKUa" Received: from relay5-d.mail.gandi.net (relay5-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::225]) by mslow3.mail.gandi.net (Postfix) with ESMTP id 48F49581A18 for ; Mon, 3 Nov 2025 14:06:30 +0000 (UTC) Received: by mail.gandi.net (Postfix) with ESMTPSA id E9C544326A; Mon, 3 Nov 2025 14:06:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=xenomai.org; s=gm1; t=1762178783; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=VLei5HccQ3sKmGNSRcGBSkp0ScdGe97Y1Le2EbFtB84=; b=grs2xKUa5Y1PAgt3lg3uO1gB1ry/1IO1In1I+ni5SdUsolajA0kwxJE7AnubC7NXqaSHtw RAdDTv+ReoJY4f4xkAXywUTh1nRqJOwwpvykLE4d7iRr0h//6nAwgqrFpy82RjrgSortYX og8erZKVa5ccv70BKBNf4ZLC8OLUdoF6a+JHREGXnIQVVIlu5gf04cDr4z1GIX5SfGk2Um 6hZotwQpLLRpQQXyf4WFnhSo2lS2el9wkP2JvRUv1vj8bo4uwW+dNB52UWOICSagR04Vyt 6G/FVnGXkZQM/EPLC3JNZQ0Wg8vQUW829sS5gYvxXB+8+3xghoxa9KCDaWwarg== From: Philippe Gerum To: Giulio Moro Cc: =?utf-8?Q?=C5=81ukasz?= Majewski , Xenomai Subject: Re: Unexpected switches to in-band In-Reply-To: <58fcd922-3a50-74c5-bfee-01cbcb7e1e6d@bela.io> (Giulio Moro's message of "Sat, 1 Nov 2025 11:33:35 -0500") References: <20251009151737.0d03b211@wsk> <20676160-4572-d92d-4b33-ff4255946345@bela.io> <87qzv9sa9c.fsf@xenomai.org> <87ikgls9kh.fsf@xenomai.org> <20251020094705.2ac256f2@wsk> <9d2bacac-8d70-f083-e926-21beee2207c2@bela.io> <87o6q1ad07.fsf@xenomai.org> <20251023155439.0170f987@wsk> <87a51djuor.fsf@xenomai.org> <20251027120535.7933c720@wsk> <20251027172505.29eecfb2@wsk> <875xbyawx7.fsf@xenomai.org> <20251029145125.71debaab@wsk> <20251030132602.2d1ccfcc@wsk> <87qzukuzy5.fsf@xenomai.org> <20251031165615.2c9f72f5@wsk> <87bjlnc9u5.fsf@xenomai.org> <20251101165957.12432bf4@wsk> <58fcd922-3a50-74c5-bfee-01cbcb7e1e6d@bela.io> User-Agent: mu4e 1.12.12; emacs 30.2 Date: Mon, 03 Nov 2025 15:06:22 +0100 Message-ID: <87cy5znrc1.fsf@xenomai.org> Precedence: bulk X-Mailing-List: xenomai@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeeffedrtdeggddujeekfedvucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuifetpfffkfdpucggtfgfnhhsuhgsshgtrhhisggvnecuuegrihhlohhuthemuceftddunecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpefhvfevufgjfhgffffkgggtsehttdertddtredtnecuhfhrohhmpefrhhhilhhiphhpvgcuifgvrhhumhcuoehrphhmseigvghnohhmrghirdhorhhgqeenucggtffrrghtthgvrhhnpedvlefhvdehkeduheevleegiedtueejgfekhfeijeefvdeijeekgeeigfejhfekgeenucfkphepvdgrtddumegvtdgrmedulegsmeeftggutdemleeklegrmeehtgegsgemsgejfhhfmegsrghfnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepvdgrtddumegvtdgrmedulegsmeeftggutdemleeklegrmeehtgegsgemsgejfhhfmegsrghfpdhhvghlohepphihrhhopdhmrghilhhfrhhomheprhhpmhesgigvnhhomhgrihdrohhrghdpnhgspghrtghpthhtohepfedprhgtphhtthhopeigvghnohhmrghisehlihhsthhsrdhlihhnuhigrdguvghvpdhrtghpthhtoheplhhukhhmrgesnhgrsghlrgguvghvrdgtohhmpdhrtghpthhtohepghhiuhhlihhosegsvghlrgdrihho X-GND-Sasl: rpm@xenomai.org Giulio Moro writes: > Hi everyone, > >> CONFIG_COMPACTION=n - it also automatically set CONFIG_MIGRATION=n >> From the Kconfig dependencies CONFIG_MIGRATION=n -> !PREEMPT_RT >> [=n] >> (i.e. it can be only enabled when PREEMPT_RT is NOT) >> I've just set CONFIG_COMPACTION=n (which also disabled the >> CONFIG_MIGRATION) and now I cannot reproduce the issue on my setup (i.e. >> v6.6.) anymore. >> It looks like those (enabled by default) config options have slipped >> in >> silently and introduced the issue... >> > > I can confirm disabling CONFIG_COMPACTION and CONFIG_MIGRATION fixed the issue for me as well. Fun fact is that I started looking over these options when I first raised the issue, but then realised that evl check did not flag them as problematic, giving me a false sense of security ... > Without knowing much about the internals, in hindsight it makes perfect sense that the process was more likely to fail early on in the lifteime of the process and/or of the kernel than after it had been running for a long time: once the memory layout has settled, it's unlikely it will get moved again. > > By the way, I was thinking that replacing an in-menuconfig warning (a > la Xenomai-3) would be nice to have, instead of having to manually run > evl check on the config file. Actually, we want both. Some automated configuration process may not give us any hint loud enough, a runtime check is always welcome, especially when providing support. -- Philippe.