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([2601:408:c180:2530:d041:4c25:86b8:e76a]) by smtp.gmail.com with ESMTPSA id e9e14a558f8ab-3a79abbebb7sm20193135ab.24.2024.11.25.12.54.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 25 Nov 2024 12:54:50 -0800 (PST) From: Waiman Long X-Google-Original-From: Waiman Long Message-ID: <88f47cea-baba-4673-9bd7-7b7c3f421008@redhat.com> Date: Mon, 25 Nov 2024 15:54:48 -0500 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] sparc/pci: Make pci_poke_lock a raw_spinlock_t. To: Guenter Roeck , Waiman Long , Sebastian Andrzej Siewior Cc: sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org, Boqun Feng , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Will Deacon , "David S. Miller" , Andreas Larsson References: <20241009161041.1018375-1-bigeasy@linutronix.de> <20241009161041.1018375-2-bigeasy@linutronix.de> <7656395b-58fc-4874-a9f3-6d934e2ef7ee@roeck-us.net> <20241125085314.1iSDFulg@linutronix.de> <20241125174336.8nEhFXIw@linutronix.de> <20241125181231.XpOsxxHx@linutronix.de> <72991b83-173e-492e-a4aa-5049304c1bd0@roeck-us.net> <5d269249-afd1-44f5-8faf-9ac11d9a3beb@redhat.com> <2a940822-b4d4-43ea-b4f7-4294043b76ea@roeck-us.net> Content-Language: en-US In-Reply-To: <2a940822-b4d4-43ea-b4f7-4294043b76ea@roeck-us.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 11/25/24 3:23 PM, Guenter Roeck wrote: > On 11/25/24 12:06, Guenter Roeck wrote: >> On 11/25/24 11:33, Waiman Long wrote: >> [ ... ] >>>> Fixing that finally gives me a clean run. Nevertheless, that makes >>>> me wonder: >>>> Should I just disable CONFIG_PROVE_RAW_LOCK_NESTING for sparc >>>> runtime tests ? >>> >>> If no one is tryng to ever enable PREEMPT_RT on SPARC, I suppose you >>> could disable CONFIG_PROVE_RAW_LOCK_NESTING to avoid the trouble. >>> >> >> SGTM. I'll do that unless someone gives me a good reason to keep it >> enabled. >> > > Actually it can not be disabled with a configuration flag. It is > automatically enabled. I'll have to disable PROVE_LOCKING to disable it. > > config PROVE_RAW_LOCK_NESTING >         bool                    <---- no longer user configurable >         depends on PROVE_LOCKING >         default y >         help >          Enable the raw_spinlock vs. spinlock nesting checks which ensure >          that the lock nesting rules for PREEMPT_RT enabled kernels are >          not violated. > > I don't really like that, and I don't understand the logic behind it, > but it is what it is. > > FWIW, the description of commit 560af5dc839 is misleading. It says > "Enable > PROVE_RAW_LOCK_NESTING _by default_" (emphasis mine). That is not what > the > commit does. It force-enables PROVE_RAW_LOCK_NESTING if PROVE_LOCKING is > enabled. It is all or nothing. > I think we can relax it by diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 5d9eca035d47..bfdbd3fa2d29 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1399,7 +1399,7 @@ config PROVE_LOCKING  config PROVE_RAW_LOCK_NESTING         bool         depends on PROVE_LOCKING -       default y +       default y if ARCH_SUPPORTS_RT         help          Enable the raw_spinlock vs. spinlock nesting checks which ensure          that the lock nesting rules for PREEMPT_RT enabled kernels are Sebastian, what do you think? Cheers, Longman > Guenter >