From: Martin Schwidefsky Date: Wed, 14 Jan 2015 16:52:33 +0000 (+0100) Subject: s390/spinlock: add compare-and-delay to lock wait loops X-Git-Tag: fixes-v4.0-rc1~134^2~17 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2c72a44ecdf2a7ceac73844226e97ed2d5dd1e82;p=pandora-kernel.git s390/spinlock: add compare-and-delay to lock wait loops Add the compare-and-delay instruction to the spin-lock and rw-lock retry loops. A CPU executing the compare-and-delay instruction stops until the lock value has changed. This is done to make the locking code for contended locks to behave better in regard to the multi- hreading facility. A thread of a core executing a compare-and-delay will allow the other threads of a core to get a larger share of the core resources. Signed-off-by: Martin Schwidefsky --- Reading git-diff-tree failed