From: Seth Jennings Date: Wed, 12 Oct 2011 19:41:00 +0000 (-0500) Subject: staging: zcache: remove zcache_direct_reclaim_lock X-Git-Tag: v3.2-rc1~169^2^2~68 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=00bf256011d362e7d61824f3cda8514f5d48585d;p=pandora-kernel.git staging: zcache: remove zcache_direct_reclaim_lock zcache_do_preload() currently does a spin_trylock() on the zcache_direct_reclaim_lock. Holding this lock intends to prevent shrink_zcache_memory() from evicting zbud pages as a result of a preload. However, it also prevents two threads from executing zcache_do_preload() at the same time. The first thread will obtain the lock and the second thread's spin_trylock() will fail (an aborted preload) causing the page to be either lost (cleancache) or pushed out to the swap device (frontswap). It also doesn't ensure that the call to shrink_zcache_memory() is on the same thread as the call to zcache_do_preload(). Additional, there is no need for this mechanism because all zcache_do_preload() calls that come down from cleancache already have PF_MEMALLOC set in the process flags which prevents direct reclaim in the memory manager. If the zcache_do_preload() call is done from the frontswap path, we _want_ reclaim to be done (which it isn't right now). This patch removes the zcache_direct_reclaim_lock and related statistics in zcache. Based on v3.1-rc8 Signed-off-by: Seth Jennings Reviewed-by: Dave Hansen Acked-by: Dan Magenheimer Signed-off-by: Greg Kroah-Hartman --- Reading git-diff-tree failed