locking/qspinlock: Fix inaccessible URL of MCS lock paper (57097124) · Commits · 戴 / test

It turns out that the URL of the MCS lock paper listed in the source code is no longer accessible. I did got question about where the paper was. This patch updates the URL to BZ 206115 which contains a copy of the paper from https://www.cs.rochester.edu/u/scott/papers/1991_TOCS_synch.pdf Signed-off-by:

Waiman Long <longman@redhat.com> Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:

Will Deacon <will@kernel.org> Link: https://lkml.kernel.org/r/20200107174914.4187-1-longman@redhat.com

kernel/locking/qspinlock.c

+7 −6

Original line number	Diff line number	Diff line
		@@ -31,14 +31,15 @@
		/*
		* The basic principle of a queue-based spinlock can best be understood
		* by studying a classic queue-based spinlock implementation called the
		* MCS lock. The paper below provides a good description for this kind
		* of lock.
		* MCS lock. A copy of the original MCS lock paper ("Algorithms for Scalable
		* Synchronization on Shared-Memory Multiprocessors by Mellor-Crummey and
		* Scott") is available at
		*
		* http://www.cise.ufl.edu/tr/DOC/REP-1992-71.pdf
		* https://bugzilla.kernel.org/show_bug.cgi?id=206115
		*
		* This queued spinlock implementation is based on the MCS lock, however to make
		* it fit the 4 bytes we assume spinlock_t to be, and preserve its existing
		* API, we must modify it somehow.
		* This queued spinlock implementation is based on the MCS lock, however to
		* make it fit the 4 bytes we assume spinlock_t to be, and preserve its
		* existing API, we must modify it somehow.
		*
		* In particular; where the traditional MCS lock consists of a tail pointer
		* (8 bytes) and needs the next pointer (another 8 bytes) of its own node to

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