Re: [PATCH 2/2] AFS: Implement shared-writable mmap

[Nick Piggin <nickpiggin@yahoo.com.au>]

Andrew Morton wrote:
> On Tue, 15 May 2007 16:52:31 +0100
> David Howells <dhowells@redhat.com> wrote:
> 
> 
>>Implement shared-writable mmap for AFS.
> 
> 
> This blows up in -mm:
> 
> fs/afs/file.c:59: error: 'filemap_nopage' undeclared here (not in a function)
> fs/afs/file.c:60: error: unknown field 'populate' specified in initializer
> fs/afs/file.c:60: error: 'filemap_populate' undeclared here (not in a function)
> 
> because Nick went and renamed half the VM and deleted the other half.

And page_mkwrite is next ;)


> I need to work out what to do with
> 
> mm-fix-fault-vs-invalidate-race-for-linear-mappings.patch
> mm-merge-populate-and-nopage-into-fault-fixes-nonlinear.patch
> mm-merge-populate-and-nopage-into-fault-fixes-nonlinear-doc-fix.patch
> mm-merge-populate-and-nopage-into-fault-fixes-nonlinear-fix.patch
> mm-merge-nopfn-into-fault.patch
> convert-hugetlbfs-to-use-vm_ops-fault.patch
> mm-remove-legacy-cruft.patch
> mm-debug-check-for-the-fault-vs-invalidate-race.patch
> mm-fix-clear_page_dirty_for_io-vs-fault-race.patch
> 
> Probably merge them, I guess.  Hugh had concerns, I think over small
> additional overhead from the lock_page()?

Yes he did. It seems to only be noticable in microbenchmarks. In my opinion
not enough to withhold pagecache corruption bug fixes.

Still, I have some lock_page speedup work that eliminates that regression
anyway.

However, Hugh hasn't exactly said yes or no yet...

-- 
SUSE Labs, Novell Inc.