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| author | David Howells <dhowells@redhat.com> | 2016-04-26 10:22:06 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-04-28 10:57:51 +0200 |
| commit | 8d4840e84871847ee1bae56a776907d08a9265f7 (patch) | |
| tree | a886a2b2502770feee97fa9cfc1e444ccfffcaa0 /Documentation/memory-barriers.txt | |
| parent | e7720af5f9ac914577e2b810d5c004cdf395fd82 (diff) | |
| download | lwn-8d4840e84871847ee1bae56a776907d08a9265f7.tar.gz lwn-8d4840e84871847ee1bae56a776907d08a9265f7.zip | |
locking/Documentation: State purpose of memory-barriers.txt
There has been some confusion about the purpose of memory-barriers.txt,
so this commit adds a statement of purpose.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: corbet@lwn.net
Cc: dave@stgolabs.net
Cc: linux-doc@vger.kernel.org
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1461691328-5429-2-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'Documentation/memory-barriers.txt')
| -rw-r--r-- | Documentation/memory-barriers.txt | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt index fb2dd35a823a..8b11e54238bf 100644 --- a/Documentation/memory-barriers.txt +++ b/Documentation/memory-barriers.txt @@ -19,6 +19,22 @@ in case of any doubt (and there are many) please ask. To repeat, this document is not a specification of what Linux expects from hardware. +The purpose of this document is twofold: + + (1) to specify the minimum functionality that one can rely on for any + particular barrier, and + + (2) to provide a guide as to how to use the barriers that are available. + +Note that an architecture can provide more than the minimum requirement +for any particular barrier, but if the architecure provides less than +that, that architecture is incorrect. + +Note also that it is possible that a barrier may be a no-op for an +architecture because the way that arch works renders an explicit barrier +unnecessary in that case. + + ======== CONTENTS ======== |