Messages in this thread | | | Date | Sun, 28 Jul 2002 18:04:03 -0700 | From | William Lee Irwin III <> | Subject | Re: [BK PATCH 2.5] Introduce 64-bit versions of PAGE_{CACHE_,}{MASK,ALIGN} |
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On Sun, Jul 28, 2002 at 05:43:25PM -0700, William Lee Irwin III wrote: >> This is so aggressive I'm obligated to pursue it. The pte_chain will >> die shortly if I get my way as it is.
On Mon, Jul 29, 2002 at 02:56:12AM +0200, Andrea Arcangeli wrote: > if you look at DaveM first full rmap implementation it never had a > pte-chain. He used the same rmap logic we always hand in linux since the > first 2.1 kernel I looked at, to handle correctly truncate against > MAP_SHARED. Unfortunately that's not very efficient and requires some > metadata allocation for anonymous pages (that's the address space > pointer, anon pages regularly doesn't have a dedicated address space), > and overhead that we never had w/o full rmap (and for inode backed > mappings we just have this info in the inode, just the shared_lock > locking isn't trivial). Hope you can came up with a better algorithm > (nevertheless also the current rmap implementation adds significant > measurable overhead in the fast paths), Rik told me a few days ago he > also wanted to drop the pte_chain, but I assume you're just in sync with him.
I've seen davem's implementation. The anonymous page metadata allocations, while they are overhead, are likely to be significantly smaller than per-pte overhead. The rest is a matter of details. You're welcome to participate with the design and/or implementation.
Cheers, Bill - 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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