Re: [patch 4/9] Guest page hinting: volatile swap cache.
- From: Dave Hansen <haveblue@xxxxxxxxxx>
- Date: Fri, 01 Sep 2006 08:52:19 -0700
On Fri, 2006-09-01 at 17:37 +0200, Martin Schwidefsky wrote:
On Fri, 2006-09-01 at 08:04 -0700, Dave Hansen wrote:
+EXPORT_SYMBOL(find_get_page_nodiscard);
+
+#endif
Is it worth having another full copy of find_get_page()? What about a
"nodiscard" argument?
That is a hard call to make. I really tried hard to avoid adding any
overhead to a system running without the feature.
The overhead being the extra (potentially unused) argument to the
function? Plus, that the function isn't inlined and thus will be unable
to have its argument optimized away?
In the worse case, we're talking about the cost of saving and restoring
the contents of a single register to the stack. In other arches, we're
talking about the push of an immediate on the stack for the call.
Yeah, it is a hard call to make, especially if you're aiming for
zero-impact.
-- Dave
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- [patch 4/9] Guest page hinting: volatile swap cache.
- From: Martin Schwidefsky
- Re: [patch 4/9] Guest page hinting: volatile swap cache.
- From: Dave Hansen
- Re: [patch 4/9] Guest page hinting: volatile swap cache.
- From: Martin Schwidefsky
- [patch 4/9] Guest page hinting: volatile swap cache.
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