Messages in this thread | | | Date | Fri, 22 Aug 2003 17:34:29 +0100 | From | Matthew Wilcox <> | Subject | Re: [parisc-linux] Re: Problems with kernel mmap (failing tst-mmap-eofsync in glibc on parisc) |
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On Fri, Aug 22, 2003 at 09:14:47AM -0700, David S. Miller wrote: > On 22 Aug 2003 09:40:37 -0500 > James Bottomley <James.Bottomley@SteelEye.com> wrote: > > The reason this doesn't happen is because the mapping is not on the > > mmap_shared list that flush_dcache_page() updates. > > flush_dcache_page() checks both the shared and non-shared mmap lists, > so if it is on _either_ list it is flushed. It does not check only > the shared list.
Gah, that's going to get really inefficient. I still think we want to split flush_dcache_page() into two operations -- flush_dcache_user() and flush_dcache_kernel(). flush_dcache_user() would flush this specific user mapping back to ram and flush_dcache_kernel() would flush the kernel mapping. Obviously we'd still want to have flush_dcache_page() as there are instances when you want to flush all user mappings and the kernel mapping back to ram.
> The VM_SHARED change you are proposing is definitely wrong.
Why is it wrong? Why should whether-or-not a mapping is read-only affect whether it's mapped shared? I can't see anything in SuS v3 that suggests we should do this.
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