linux/tools/memory-model/Documentation, branch v4.19

tools/memory-model: Rename litmus tests to comply to norm7

2018-07-17T07:30:36Z

norm7 produces the 'normalized' name of a litmus test, when the test can be generated from a single cycle that passes through each process exactly once. The commit renames such tests in order to comply to the naming scheme implemented by this tool. Signed-off-by: Andrea Parri Signed-off-by: Paul E. McKenney Acked-by: Alan Stern Cc: Akira Yokosawa Cc: Boqun Feng Cc: David Howells Cc: Jade Alglave Cc: Linus Torvalds Cc: Luc Maranget Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: linux-arch@vger.kernel.org Cc: parri.andrea@gmail.com Link: http://lkml.kernel.org/r/20180716180605.16115-14-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar

tools/memory-model/Documentation: Fix typo, smb->smp

2018-07-17T07:30:35Z

The tools/memory-model/Documentation/explanation.txt file says "For each other CPU C', smb_wmb() forces all po-earlier stores" This commit therefore replaces the "smb_wmb()" with "smp_wmb()". Signed-off-by: Yauheni Kaliuta Signed-off-by: Paul E. McKenney Acked-by: Alan Stern Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akiyks@gmail.com Cc: boqun.feng@gmail.com Cc: dhowells@redhat.com Cc: j.alglave@ucl.ac.uk Cc: linux-arch@vger.kernel.org Cc: luc.maranget@inria.fr Cc: npiggin@gmail.com Cc: parri.andrea@gmail.com Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/20180716180605.16115-13-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar

tools/memory-model: Remove ACCESS_ONCE() from recipes

2018-07-17T07:29:34Z

Since commit: b899a850431e2dd0 ("compiler.h: Remove ACCESS_ONCE()") ... there has been no definition of ACCESS_ONCE() in the kernel tree, and it has been necessary to use READ_ONCE() or WRITE_ONCE() instead. Let's update the exmaples in recipes.txt likewise for consistency, using READ_ONCE() for reads. Signed-off-by: Mark Rutland Signed-off-by: Paul E. McKenney Acked-by: Andrea Parri Cc: Akira Yokosawa Cc: Alan Stern Cc: Boqun Feng Cc: David Howells Cc: Jade Alglave Cc: Linus Torvalds Cc: Luc Maranget Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: linux-arch@vger.kernel.org Cc: parri.andrea@gmail.com Link: http://lkml.kernel.org/r/20180716180605.16115-5-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar

tools/memory-model: Add reference for 'Simplifying ARM concurrency'

2018-05-15T06:11:19Z

The paper discusses the revised ARMv8 memory model; such revision had an important impact on the design of the LKMM. Signed-off-by: Andrea Parri Signed-off-by: Paul E. McKenney Cc: Akira Yokosawa Cc: Alan Stern Cc: Andrew Morton Cc: Boqun Feng Cc: David Howells Cc: Jade Alglave Cc: Linus Torvalds Cc: Luc Maranget Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: linux-arch@vger.kernel.org Cc: parri.andrea@gmail.com Link: http://lkml.kernel.org/r/1526340837-12222-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar

tools/memory-model: Update ASPLOS information

2018-05-15T06:11:18Z

ASPLOS 2018 was held in March: make sure this is reflected in header comments and references. Signed-off-by: Andrea Parri Signed-off-by: Paul E. McKenney Cc: Akira Yokosawa Cc: Alan Stern Cc: Andrew Morton Cc: Boqun Feng Cc: David Howells Cc: Jade Alglave Cc: Linus Torvalds Cc: Luc Maranget Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: linux-arch@vger.kernel.org Cc: parri.andrea@gmail.com Link: http://lkml.kernel.org/r/1526340837-12222-18-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar

tools/memory-order: Update the cheat-sheet to show that smp_mb__after_atomic() orders later RMW operations

2018-05-15T06:11:16Z

The current cheat sheet does not claim that smp_mb__after_atomic() orders later RMW atomic operations, which it must, at least against earlier RMW atomic operations and whatever precedes them. This commit therefore adds the needed "Y". Signed-off-by: Paul E. McKenney Acked-by: Alan Stern Cc: Andrew Morton Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: akiyks@gmail.com Cc: boqun.feng@gmail.com Cc: dhowells@redhat.com Cc: j.alglave@ucl.ac.uk Cc: linux-arch@vger.kernel.org Cc: luc.maranget@inria.fr Cc: npiggin@gmail.com Cc: parri.andrea@gmail.com Link: http://lkml.kernel.org/r/1526340837-12222-6-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar

tools/memory-order: Improve key for SELF and SV

2018-05-15T06:11:16Z

The key for "SELF" was missing completely and the key for "SV" was a bit obtuse. This commit therefore adds a key for "SELF" and improves the one for "SV". Reported-by: Paolo Bonzini Signed-off-by: Paul E. McKenney Acked-by: Alan Stern Cc: Andrew Morton Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: akiyks@gmail.com Cc: boqun.feng@gmail.com Cc: dhowells@redhat.com Cc: j.alglave@ucl.ac.uk Cc: linux-arch@vger.kernel.org Cc: luc.maranget@inria.fr Cc: npiggin@gmail.com Cc: parri.andrea@gmail.com Link: http://lkml.kernel.org/r/1526340837-12222-5-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar

tools/memory-model: Fix cheat sheet typo

2018-05-15T06:11:16Z

"RWM" should be "RMW". Signed-off-by: Paolo Bonzini Signed-off-by: Paul E. McKenney Cc: Andrew Morton Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: akiyks@gmail.com Cc: boqun.feng@gmail.com Cc: dhowells@redhat.com Cc: j.alglave@ucl.ac.uk Cc: linux-arch@vger.kernel.org Cc: luc.maranget@inria.fr Cc: npiggin@gmail.com Cc: parri.andrea@gmail.com Cc: stern@rowland.harvard.edu Link: http://lkml.kernel.org/r/1526340837-12222-4-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar

tools/memory-model: Redefine rb in terms of rcu-fence

2018-05-15T06:11:16Z

This patch reorganizes the definition of rb in the Linux Kernel Memory Consistency Model. The relation is now expressed in terms of rcu-fence, which consists of a sequence of gp and rscs links separated by rcu-link links, in which the number of occurrences of gp is >= the number of occurrences of rscs. Arguments similar to those published in http://diy.inria.fr/linux/long.pdf show that rcu-fence behaves like an inter-CPU strong fence. Furthermore, the definition of rb in terms of rcu-fence is highly analogous to the definition of pb in terms of strong-fence, which can help explain why rcu-path expresses a form of temporal ordering. This change should not affect the semantics of the memory model, just its internal organization. Signed-off-by: Alan Stern Signed-off-by: Paul E. McKenney Reviewed-by: Boqun Feng Reviewed-by: Andrea Parri Cc: Andrew Morton Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: akiyks@gmail.com Cc: dhowells@redhat.com Cc: j.alglave@ucl.ac.uk Cc: linux-arch@vger.kernel.org Cc: luc.maranget@inria.fr Cc: npiggin@gmail.com Link: http://lkml.kernel.org/r/1526340837-12222-2-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar

tools/memory-model: Rename link and rcu-path to rcu-link and rb

2018-05-15T06:11:15Z

This patch makes a simple non-functional change to the RCU portion of the Linux Kernel Memory Consistency Model by renaming the "link" and "rcu-path" relations to "rcu-link" and "rb", respectively. The name "link" was an unfortunate choice, because it was too generic and subject to confusion with other meanings of the same word, which occur quite often in LKMM documentation. The name "rcu-path" is not very appropriate, because the relation is analogous to the happens-before (hb) and propagates-before (pb) relations -- although that fact won't become apparent until the second patch in this series. Signed-off-by: Alan Stern Signed-off-by: Paul E. McKenney Acked-by: Andrea Parri Cc: Andrew Morton Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: akiyks@gmail.com Cc: boqun.feng@gmail.com Cc: dhowells@redhat.com Cc: j.alglave@ucl.ac.uk Cc: linux-arch@vger.kernel.org Cc: luc.maranget@inria.fr Cc: npiggin@gmail.com Link: http://lkml.kernel.org/r/1526340837-12222-1-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar