On 14 September 2010 01:21, Johannes Stezenbach <js@xxxxxxxxx> wrote: > On Fri, Sep 10, 2010 at 06:02:48PM +0200, Johannes Stezenbach wrote: >> >> Linear read heuristic might be a good guess, but it would >> be nice to hear a comment from a vm/fs expert which >> confirms this works as intended. > > Apparently I'm unworthy to get a response from someone knowledgable :-( > > Anyway I found lmdd (from lmbench) can do random reads, > and indeed causes the data to enter the block (page?) cache, > replacing the previous data. I am no expert, but what did you think would happen if you did dd twice from /dev/zero? but... Honestly what do you think will be cached? If you want 'COW', use btrfs. -- Conscience doth make cowards of us all. -- Shakespeare -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>