Messages in this thread | | | Date | Mon, 24 Sep 2007 20:24:26 +0100 | From | Christoph Hellwig <> | Subject | Re: [PATCH 24/25] r/o bind mounts: track number of mount writers |
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On Mon, Sep 24, 2007 at 12:10:35PM -0700, Andrew Morton wrote: > > As we already say in various messages the percpu counters in here > > look rather fishy. I'd recomment to take a look at the per-cpu > > superblock counters in XFS as they've been debugged quite well > > now and could probably be lifted into a generic library for this > > kind of think. The code is mostly in fs/xfs/xfs_mount.c can > > can be spotted by beeing under #ifdef HAVE_PERCPU_SB. > > > > It also handles cases like hotplug cpu nicely that this code > > seems to work around by always iterating over all possible cpus > > which might not be nice on a dual core laptop with a distro kernel > > that also has to support big iron. > > hm. How come xfs invented a new version of percpu_counters?
This code actually predates the generic percpu_counters even if it was merged to mainline later. Neither Dave who wrote it nor me who reviewed it before it was merged thought of percpu_counters probably. Then again this code is considerably more complex due to features actually needed in a very hot fastpath. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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