Messages in this thread |  | | Date | Sat, 17 May 2003 20:42:49 +0200 | From | Andrea Arcangeli <> | Subject | Re: Race between vmtruncate and mapped areas? |
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On Sat, May 17, 2003 at 11:19:39AM -0700, Paul McKenney wrote: > > > > > > On Thu, May 15, 2003 at 02:20:00AM -0700, Andrew Morton wrote: > > > Andrea Arcangeli <andrea@suse.de> wrote: > > > > > > > > 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. > > > > > I do think that we should push the revalidate operation over into the > vm_ops. > > > That'll require an extra arg to ->nopage, but it has a spare one anyway > (!). > > > > 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)
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