From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 22D6FC43603 for ; Thu, 12 Dec 2019 09:01:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E37A622B48 for ; Thu, 12 Dec 2019 09:01:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="EMYGgAge" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728261AbfLLJBk (ORCPT ); Thu, 12 Dec 2019 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<20191211201634.GA13407@ls3530.fritz.box> <63f37f01-6ae1-96e2-815b-aa48eb1f1c31@bell.net> From: Helge Deller Autocrypt: addr=deller@gmx.de; keydata= mQINBF3Ia3MBEAD3nmWzMgQByYAWnb9cNqspnkb2GLVKzhoH2QD4eRpyDLA/3smlClbeKkWT HLnjgkbPFDmcmCz5V0Wv1mKYRClAHPCIBIJgyICqqUZo2qGmKstUx3pFAiztlXBANpRECgwJ r+8w6mkccOM9GhoPU0vMaD/UVJcJQzvrxVHO8EHS36aUkjKd6cOpdVbCt3qx8cEhCmaFEO6u CL+k5AZQoABbFQEBocZE1/lSYzaHkcHrjn4cQjc3CffXnUVYwlo8EYOtAHgMDC39s9a7S90L 69l6G73lYBD/Br5lnDPlG6dKfGFZZpQ1h8/x+Qz366Ojfq9MuuRJg7ZQpe6foiOtqwKym/zV dVvSdOOc5sHSpfwu5+BVAAyBd6hw4NddlAQUjHSRs3zJ9OfrEx2d3mIfXZ7+pMhZ7qX0Axlq Lq+B5cfLpzkPAgKn11tfXFxP+hcPHIts0bnDz4EEp+HraW+oRCH2m57Y9zhcJTOJaLw4YpTY GRUlF076vZ2Hz/xMEvIJddRGId7UXZgH9a32NDf+BUjWEZvFt1wFSW1r7zb7oGCwZMy2LI/G aHQv/N0NeFMd28z+deyxd0k1CGefHJuJcOJDVtcE1rGQ43aDhWSpXvXKDj42vFD2We6uIo9D 1VNre2+uAxFzqqf026H6cH8hin9Vnx7p3uq3Dka/Y/qmRFnKVQARAQABtBxIZWxnZSBEZWxs ZXIgPGRlbGxlckBnbXguZGU+iQJRBBMBCAA7AhsDBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheA 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notjunk:1;V03:K0:bXgwcS6lCFg=:20qeWGzMrdmsayfMbfv9uK +GNQtpaXyvUisR4DxOPRbUUo5NCZ+CHnVRdOK78N8M7kmtWFny7j+tmbuJNy0820M1JLJ5qwO 42PC3DmaVbtrnh0LHoqejnymuv80NA4WxuQ6MNmkmQ5/dKZr/PQ7/A00SXUJFYUTpZg4Qvdz6 WFdjPZKdnUhJ4ERGKGakZI7wIdnd32B+TxsCFFZgIROxBngW8My/LKwPtetP+arEU3FRQa42W VQyw73mwjzRU7pSEtG1eHaBjHGvcN6HUWKC0ZUdLfaVaNIO8FeBy/v8c9t32EyuIZr2Ux+2jp z6dVtC7mwDxmeuPmcSBts9aYbz9dfo/PfnmtM0P2SvyVNUGpdM/D9EA3nD9cwdk0BNVlr0APN xshGWhwaD1gWihRcj+t7fU/5omoATBZeGUftdgUaTeOgsC0fK5Hh4IZ7JaO5zetg1eiL2X3JN +2CK0ih1qil3V9ZDHylEnf0oPAfcH/+tTIHYCbVcBNEYoz0WTdemnj4shmTezv9KduGTS91RK thp9LpXlFGmTAJPGXljaThv+A66JjTdcR1pb+EewNNYx9IQ3gWinmSP1ifPskY1fjomjbnbKO 3FiKkFbBaaMjU7MVSMuwju2QfkMMJfAf/5TDMpL16rsoIjKeeBwR2tm2jLLO1bxTF77hwHS9J odQRJESpwXIa6cHaJCu/3sxqvRw9WH/QUDjZpTXJwy6P1C+A8yPiWe0mJbtwID6SNavZQbiRw qN4GgTrpPX3QrmEx1JrFCkCXbbAntiVGs4D0KZek3obZsgpDa4YMMJAXn8FA6occI4bxy+T4S sPB2960ds/mos/cD/wV5kS2GmyOOusQw6Q9cXUfkpk9X/pRgJxCV2RFuy/5N+ZP+W0cAv3cI3 cV8NVq3WB/92s+0/zMwqXpGoJ7CDK2bJe618DF8Dcxid35ug0BQz4VoDaCuLO6okMyrqOPPtC msqDNlQRzO29V+8oDntbMGMnoQDQZh96QRFXs4MDVzPjpIbc2dQ8fAk74Fraz1hoODyDaNQVV TxassoaekFQcd2RAfz1HxqYjlAMXDFD44bwefhxHeH4vQt+hljNqvQkYUOUWT3zBzuEdUkBSv x/7jDLmU+zIqRwwAIXhlz3nMcHrmxUyxxF4nTKfGZjt3nGYxOnPg8bIJt9CZu0zT2vegOHHgQ aZfXCAjW/7BQVeVg5cBmTiibBdCCEKGMQuVYYgFrEZMNXSg7E8spqN8rF8jspSePDd0UWYnz+ mdxGW+LlUGyNjfKJurxrpilpk4OqQX0mGyw73qQ== Sender: linux-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org On 11.12.19 22:29, John David Anglin wrote: > On 2019-12-11 3:16 p.m., Helge Deller wrote: >> Up to now we tried to optimize the ldcw usage by using the coherent >> completer of this command, which operates on the cache (instead of >> memory) and thus might speed up things, and which was enabled by defaul= t >> on our 64bit kernel build. >> >> But we still see runtime locking problems, so this patch changes it bac= k >> to use ldcw for 32- and 64-bit kernels, and live-patches it at runtime >> to use the coherent completer when running on a uniprocessor machine. > I'm not convinced this is the problem.=C2=A0 Nominally, every PA 2.0 mac= hine that we support is coherent. > Is there evidence that this actually helps?=C2=A0 I did a test where I s= witched "ldcw,co" to "ldcw" and > didn't find a significant difference.=C2=A0 So, I left the default assum= ption that most PA 2.0 machines > are coherent in gcc. > > I'm seeing different behavior for pthread_mutex_lock/pthread_mutex_unloc= k with different > glibc versions.=C2=A0 The locking issues also seem to vary from one kern= el version to the next. > > I don't know that we can blame the two build failures of acl2_8.1dfsg-6 = on phantom on a > locking issue, but phantom failed twice at the same pwasoint.=C2=A0 In b= oth cases, cc1 terminated with > a segmentation fault.=C2=A0 Yet, mx3210 has been chugging away for more = than a day on the package. > It also built -4 and -5. > > I don't have a clue what's really wrong but I suspect the slowness of ou= r locking infrastructure > is what exposes these issues. > > I've seen one issue in user space where a pointer to a mutex got corrupt= ed in apt-cacher-ng. > If I remember correctly, the LWS locking code was spinning with a pointe= r value of 0x12.=C2=A0 I think > the code should have faulted but the thread stuck.=C2=A0 Had to systemct= l restart apt-cacher-ng. Dave, thanks for your feedback! I'm neither convinced that this helps, nor did I tested it any further tha= n just booting. My main concern is the stuck kernel threads which happen seldom on the big= ger debian buildd servers. For now I'll not apply my patch for upstream kernels, but will keep it in = patchwork. Helge