On Fri, Nov 02, 2007 at 10:05:37AM -0400, Rik van Riel wrote: > On Fri, 2 Nov 2007 07:42:20 +0100 > Nick Piggin <[EMAIL PROTECTED]> wrote: > > > On Thu, Nov 01, 2007 at 06:19:41PM -0700, Linus Torvalds wrote: > > > > > > > > > On Thu, 1 Nov 2007, Rik van Riel wrote: > > > > > > > > Larry Woodman managed to wedge the VM into a state where, on his > > > > 4x dual core system, only 2 cores (on the same CPU) could get the > > > > zone->lru_lock overnight. The other 6 cores on the system were > > > > just spinning, without being able to get the lock. > > > > That's quite incredible, considering that the CPUs actually _taking_ > > the locks also drop the locks and do quite a bit of work before taking > > them again (ie. they take them to pull pages off the LRU, but then > > do a reasonable amount of work to remove each one from pagecache > > before refilling from the LRU). > > > > Possibly actually that is a *more* difficult case for the HW to > > handle: once the CPU actually goes away and operates on other > > cachelines, it may get a little more difficult to detect that it is > > causing starvation issues. > > In case of the zone->lru_lock, grabbing the spinlock does > not mean that the process is letting go of the cacheline. > > On the contrary, once the spinlock has been grabbed, the > real cacheline prodding begins.
I didn't say that, though. Obviously the hardware can't do anything about starvating until a lock is released. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/