The following commit has been merged into the locking/core branch of tip: Commit-ID: 8881e7a774a8d14088d6c6fde8730660f74a3642 Gitweb: https://git.kernel.org/tip/8881e7a774a8d14088d6c6fde8730660f74a3642 Author: Paul E. McKenney <paulmck@xxxxxxxxxx> AuthorDate: Fri, 06 Nov 2020 09:58:01 -08:00 Committer: Paul E. McKenney <paulmck@xxxxxxxxxx> CommitterDate: Mon, 04 Jan 2021 14:40:49 -08:00 tools/memory-model: Tie acquire loads to reads-from This commit explicitly makes the connection between acquire loads and the reads-from relation. It also adds an entry for happens-before, and refers to the corresponding section of explanation.txt. Reported-by: Boqun Feng <boqun.feng@xxxxxxxxx> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> --- tools/memory-model/Documentation/glossary.txt | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/tools/memory-model/Documentation/glossary.txt b/tools/memory-model/Documentation/glossary.txt index 79acb75..b2da636 100644 --- a/tools/memory-model/Documentation/glossary.txt +++ b/tools/memory-model/Documentation/glossary.txt @@ -33,10 +33,11 @@ Acquire: With respect to a lock, acquiring that lock, for example, acquire loads. When an acquire load returns the value stored by a release store - to that same variable, then all operations preceding that store - happen before any operations following that load acquire. + to that same variable, (in other words, the acquire load "reads + from" the release store), then all operations preceding that + store "happen before" any operations following that load acquire. - See also "Relaxed" and "Release". + See also "Happens-Before", "Reads-From", "Relaxed", and "Release". Coherence (co): When one CPU's store to a given variable overwrites either the value from another CPU's store or some later value, @@ -119,6 +120,11 @@ Fully Ordered: An operation such as smp_mb() that orders all of that orders all of its CPU's prior accesses, itself, and all of its CPU's subsequent accesses. +Happens-Before (hb): A relation between two accesses in which LKMM + guarantees the first access precedes the second. For more + detail, please see the "THE HAPPENS-BEFORE RELATION: hb" + section of explanation.txt. + Marked Access: An access to a variable that uses an special function or macro such as "r1 = READ_ONCE(x)" or "smp_store_release(&a, 1)".
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