Messages in this thread | | | Date | Sat, 1 Feb 2020 08:06:29 -0600 | From | Segher Boessenkool <> | Subject | Re: [PATCH] powerpc/32s: Don't flush all TLBs when flushing one page |
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On Sat, Feb 01, 2020 at 08:27:03AM +0100, Christophe Leroy wrote: > Le 31/01/2020 à 20:38, Segher Boessenkool a écrit : > >On Fri, Jan 31, 2020 at 05:15:20PM +0100, Christophe Leroy wrote: > >>Le 31/01/2020 à 16:51, Segher Boessenkool a écrit : > >>>On Fri, Jan 31, 2020 at 03:37:34PM +0000, Christophe Leroy wrote: > >>>>When the range is a single page, do a page flush instead. > >>> > >>>>+ start &= PAGE_MASK; > >>>>+ end = (end - 1) | ~PAGE_MASK; > >>>> if (!Hash) { > >>>>- _tlbia(); > >>>>+ if (end - start == PAGE_SIZE) > >>>>+ _tlbie(start); > >>>>+ else > >>>>+ _tlbia(); > >>>> return; > >>>> } > >>> > >>>For just one page, you get end - start == 0 actually? > >> > >>Oops, good catch. > >> > >>Indeed you don't get PAGE_SIZE but (PAGE_SIZE - 1) for just one page. > > > >You have all low bits masked off in both start and end, so you get zero. > >You could make the condion read "if (start == end)? > > No, in end the low bits are set, that's a BIT OR with ~PAGE_MASK, so it > sets all low bits to 1.
Oh, wow, yes, I cannot read apparently.
Maybe there are some ROUND_DOWN and ROUND_UP macros you could use?
Segher
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