Messages in this thread | | | Date | Tue, 13 Mar 2007 04:27:42 -0800 | From | Andrew Morton <> | Subject | Re: [QUICKLIST 0/4] Arch independent quicklists V2 |
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> On Tue, 13 Mar 2007 04:17:26 -0700 (PDT) Christoph Lameter <clameter@sgi.com> wrote: > On Tue, 13 Mar 2007, Andrew Morton wrote: > > > > On Tue, 13 Mar 2007 00:13:25 -0700 (PDT) Christoph Lameter <clameter@sgi.com> wrote: > > > Page table pages have the characteristics that they are typically zero > > > or in a known state when they are freed. > > > > Well if they're zero then perhaps they should be released to the page > > allocator to satisfy the next __GFP_ZERO request. If that request is > > for a pagetable page, we break even (except we get to remove > > special-case code). If that __GFP_ZERO allocation was or some > > application other than for a pagetable, we win. > > Nope that wont work. > > 1. We need to support other states of pages other than zeroed.
What does this mean?
> 2. Prezeroing does not make much sense if a large portion of the > page is being used. Performance is better if the whole page > is zeroed directly before use.Prezeroing only makes sense for sparse > allocations like the page table pages.
This is not related to the above discussion.
> > (Will require some work in the page allocator) > > (That work will open the path to using the idle thread to prezero pages) > > I already tried that 3 years ago and there was *no* benefit for usual > users of the a page allocator. The advantage exists only if a small > portion of the page is used. F.e. For one cacheline there was a 4x > improvement. See lkml archives for prezeroing.
Unsurprised. Were non-temporal stores tried? - 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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