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/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
| |
 |