Wip claim 2 #3
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Wip claim 2 #3
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added 4 commits
December 8, 2014 16:41
Signed-off-by: Matt Benjamin <[email protected]>
Formerly known as "strong claim," this change introduces a new sharable() property to ceph::buffer::raw objects, which can be used to prevent unplanned sharing of buffers. The default value of sharable() is true, but derived classes may override this. For example, Accelio message buffers may point to registered or pool-allocated memory which should not be held for long periods. Cloning of non-sharable buffers is now the unmarked case, so is performed automatically in the buffer::list copy constructor. Low-level operations should allow explicit volatile sharing, so copying a buffer::list:iterator or a buffer::ptr works as normal. For explicit sharing of "non-sharable" buffers, a new boolean is added to the public claim_* methods, and a buffer::list::share method is also added, to share an entire sequence. Signed-off-by: Vu Pham <[email protected]> Signed-off-by: Matt Benjamin <[email protected]> Signed-off-by: Matt Benjamin <[email protected]> Conflicts: src/include/buffer.h Signed-off-by: Matt Benjamin <[email protected]> Conflicts: src/common/buffer.cc Signed-off-by: Matt Benjamin <[email protected]> new naming for "strong claim": clone_nonsharable Signed-off-by: Matt Benjamin <[email protected]>
This change restores volatile sharing semantics in the Message decode path, and also in the OSD write path for FileStore/FileJournal. This can be verified with a breakpoint set at the clone/COW case in buffer::ptr::clone_nonsharable(currently buffer.cc:690). Signed-off-by: Matt Benjamin <[email protected]>
Signed-off-by: Matt Benjamin <[email protected]>
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The new "sharable" language still seems imperfect, but hopefully better than volatile. We can change it again if needed.