On Mon, Aug 08, 2005 at 06:31:52PM +0200, Manfred Spraul wrote: > Dipankar Sarma wrote: > > >Hugh, could you please try this with the experimental patch below ? > >Manfred, is it safe to decrement nr_files in file_free() > >instead of the destructor ? I can't see any problem. > > > > > > > The ctor/dtor are only called when new objects are created, not on every > kmem_cache_alloc/kmem_cache_free. Thus I would expect that the counter > becomes negative on builds without CONFIG_DEBUG_SLAB. > Thus increase in the ctor and decrease in file_free() is the wrong > thing. If you want to move the decrease from the dtor to file_free, then > you must move the increase, too. > But: IIRC the counters were moved to the ctor/dtor for performance > reasons, I'd guess mbligh ran into cache line trashing on the > filp_count_lock spinlock with reaim or something like that.
Ah, so the whole idea was to inc/dec nr_files less often so that we reduce contention on filp_count_lock, right ? This however causes skews nr_files by the size of the slab array, AFAICS. Since we check nr_files before we allocate files from slab, the check seems inaccurate. Anyway, I guess, I need to look at scaling the file counting first. Thanks Dipankar - 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/
