Messages in this thread | | | Date | Mon, 12 Oct 2009 18:03:12 +0100 | From | Russell King <> | Subject | Re: [PATCH] [ARM] force dcache flush if dcache_dirty bit set |
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On Mon, Oct 12, 2009 at 05:09:53PM +0100, Hugh Dickins wrote: > Sorry to muddy the waters on this, if you and Dave are sure that > you have the right fix, down in your architectures, and that fix > isn't going to hurt your performance significantly.
If I look at the issue from this point of view:
- we are using PG_arch_1 to delay cache handling for the page
- if PG_arch_1 is set on a page, we set it explicitly because we didn't do some flushing between the allocation of the page and mapping it into userspace
- if a page with PG_arch_1 set ever gets to userspace, this can only be because we did the lazy flushing thing
I don't see that there should have been any bearing on whether a page has a mapping or not when we get to update_mmu_cache. The issue here is that > if PG_arch_1 is set on a page, then we didn't flush it at the time when we believed it was appropriate to do so. <
Tell me I'm wrong (having only just sent it to Linus...)
-- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of:
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