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[103.168.172.200]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6fb5011ef19sm33090246d6.38.2025.06.17.10.13.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Jun 2025 10:13:13 -0700 (PDT) Received: from phl-compute-02.internal (phl-compute-02.phl.internal [10.202.2.42]) by mailfauth.phl.internal (Postfix) with ESMTP id 4A83D1200043; Tue, 17 Jun 2025 13:13:13 -0400 (EDT) Received: from phl-mailfrontend-02 ([10.202.2.163]) by phl-compute-02.internal (MEProxy); Tue, 17 Jun 2025 13:13:13 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeeffedrtddvgdejhecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpggftfghnshhusghstghrihgsvgdpuffr tefokffrpgfnqfghnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnth hsucdlqddutddtmdenucfjughrpeffhffvvefukfhfgggtuggjsehttdertddttddvnecu hfhrohhmpeeuohhquhhnucfhvghnghcuoegsohhquhhnrdhfvghnghesghhmrghilhdrtg homheqnecuggftrfgrthhtvghrnhephedugfduffffteeutddvheeuveelvdfhleelieev tdeguefhgeeuveeiudffiedvnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpe hmrghilhhfrhhomhepsghoqhhunhdomhgvshhmthhprghuthhhphgvrhhsohhnrghlihht hidqieelvdeghedtieegqddujeejkeehheehvddqsghoqhhunhdrfhgvnhhgpeepghhmrg hilhdrtghomhesfhhigihmvgdrnhgrmhgvpdhnsggprhgtphhtthhopeejpdhmohguvgep shhmthhpohhuthdprhgtphhtthhopehllhhonhhgsehrvgguhhgrthdrtghomhdprhgtph htthhopegrlhgvgihjlhiihhgvnhhgsehgmhgrihhlrdgtohhmpdhrtghpthhtohepphgv thgvrhiisehinhhfrhgruggvrggurdhorhhgpdhrtghpthhtohepfihilhhlsehkvghrnh gvlhdrohhrghdprhgtphhtthhopehlihhnuhigqdhkvghrnhgvlhesvhhgvghrrdhkvghr nhgvlhdrohhrghdprhgtphhtthhopegrlhgvgihjlhiihhgvnhhgsehtvghntggvnhhtrd gtohhmpdhrtghpthhtohepsghoqhhunhesfhhigihmvgdrnhgrmhgv X-ME-Proxy: Feedback-ID: iad51458e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 17 Jun 2025 13:13:12 -0400 (EDT) Date: Tue, 17 Jun 2025 10:13:12 -0700 From: Boqun Feng To: Waiman Long Cc: alexjlzheng@gmail.com, peterz@infradead.org, will@kernel.org, linux-kernel@vger.kernel.org, Jinliang Zheng Subject: Re: [PATCH] locking/rwsem: use OWNER_NONSPINNABLE directly instead of OWNER_SPINNABLE Message-ID: References: <20250610130158.4876-1-alexjlzheng@tencent.com> <7a006014-bf6e-4480-bd61-b0333c74e3a4@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7a006014-bf6e-4480-bd61-b0333c74e3a4@redhat.com> On Fri, Jun 13, 2025 at 01:52:43AM -0400, Waiman Long wrote: > > On 6/10/25 9:01 AM, alexjlzheng@gmail.com wrote: > > From: Jinliang Zheng > > > > After commit 7d43f1ce9dd0 ("locking/rwsem: Enable time-based spinning on > > reader-owned rwsem"), OWNER_SPINNABLE contains all possible values except > > OWNER_NONSPINNABLE, namely OWNER_NULL | OWNER_WRITER | OWNER_READER. > > > > Therefore, it is better to use OWNER_NONSPINNABLE directly to determine > > whether to exit optimistic spin. > > > > And, remove useless OWNER_SPINNABLE to simplify the code. > > > > Signed-off-by: Jinliang Zheng > > --- > > kernel/locking/rwsem.c | 4 +--- > > 1 file changed, 1 insertion(+), 3 deletions(-) > > > > diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c > > index 2ddb827e3bea..8572dba95af4 100644 > > --- a/kernel/locking/rwsem.c > > +++ b/kernel/locking/rwsem.c > > @@ -727,8 +727,6 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem) > > return ret; > > } > > -#define OWNER_SPINNABLE (OWNER_NULL | OWNER_WRITER | OWNER_READER) > > - > > static inline enum owner_state > > rwsem_owner_state(struct task_struct *owner, unsigned long flags) > > { > > @@ -835,7 +833,7 @@ static bool rwsem_optimistic_spin(struct rw_semaphore *sem) > > enum owner_state owner_state; > > owner_state = rwsem_spin_on_owner(sem); > > - if (!(owner_state & OWNER_SPINNABLE)) > > + if (owner_state == OWNER_NONSPINNABLE) > > break; > > /* > > Right, OWNER_SPINNABLE is no longer needed after commit 7d43f1ce9dd0. > > Acked-by: Waiman Long > Queued for more tests and reviews, thank you both! Regards, Boqun