Messages in this thread | | | Date | Tue, 29 Jan 2002 11:33:19 +1100 | From | Rusty Russell <> | Subject | Re: [RFC] Peeling off dcache_lock |
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On Fri, 25 Jan 2002 15:00:00 +0530 Dipankar Sarma <dipankar@in.ibm.com> wrote:
> Since there has been speculation about the throughput #s for lower end, > I have put up the comparison graph in the same page > (http://lse.sf.net/locking/dcache/dcache_lock.html).
Have you thought about getting rid of the lru list altogether, and traverse one chain at a time in prune_dcache, using the referenced bit as a straight clock algorithm:
spin_lock(&dentry->d_lock); if (atomic_read(dentry->dcount) == 0) { if (dentry->d_vfs_flags & DCACHE_REFERENCED) dentry->d_vfs_flags &= ~DCACHE_REFERENCED; else prune_one_dentry(dentry); } spin_unlock(&dentry->d_lock);
This can be optimized by doing a dcount check outside the loop, and the global dcache lock can be dropped between each hash chain, and we can store the last traversed hash chain in a static var, protected by the global lock.
I'm just not sure how much the "semi" LRU wins us... Rusty. -- Anyone who quotes me in their sig is an idiot. -- Rusty Russell. - 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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