Re: 2.4.10pre13aa1

[Manfred Spraul]

 >> with only the dirty bit set?  Does somebody know for sure? I can
 >> imagine the cpu finding the tlb state writeable, and issuing
 >> just a locked bit test and set in the pte without caring to
 >> check if the pte is zero or not.
 >>
 >> If the cpu just set the bit this patch will avoid to lose a shared
 >> mapping update. Otherwise it's a safe noop so I keep it applied
 >> until this issue is sorted out
 >
 >I've tested this on all the machines I could get my hands on, and every
 >single CPU will take a page fault if the pte is not present on dirtying
 >the page.  If people are truely paranoid, then make it a boot time
 > assertion.
 >

I don't think that this is a valid argument:
you are testing on i386 and make design decisions for the architecture
independant part.

I'd prefer ptep_get_and_clear_and_flush(), then the arch part can do
what's needed to get the final pte value. (if a single page is modified,
otherwise the arch can define a suitable mmu_gather)

--
     Manfred