On Sat, May 17, 2003 at 11:19:39AM -0700, Paul McKenney wrote:

quoted

On Thu, May 15, 2003 at 02:20:00AM -0700, Andrew Morton wrote:

quoted

Andrea Arcangeli [off-list ref] wrote:

quoted

and it's still racy

damn, and it just booted ;)

I'm just a little bit concerned over the ever-expanding inode.  Do you
think the dual sequence numbers can be replaced by a single generation
counter?

yes, I wrote it as a single counter first, but was unreadable and it had
more branches, so I added the other sequence number to make it cleaner.
I don't mind another 4 bytes, that cacheline should be hot anyways.

quoted

I do think that we should push the revalidate operation over into the

vm_ops.

quoted

quoted

That'll require an extra arg to ->nopage, but it has a spare one anyway

(!).

quoted

not sure why you need a callback, the lowlevel if needed can serialize
using the same locking in the address space that vmtruncate uses. I
would wait a real case need before adding a callback.

FYI, we verified that the revalidate callback could also do the same
job that the proposed nopagedone callback does -- permitting filesystems
that provide their on vm_operations_struct to avoid the race between
page faults and invalidating a page from a mapped file.

don't you need two callbacks to avoid the race? (really I mean, to call
two times a callback, the callback can be also the same)

Andrea
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