Messages in this thread | | | Date | Mon, 22 Oct 2007 21:16:17 +0100 (BST) | From | Hugh Dickins <> | Subject | Re: msync(2) bug(?), returns AOP_WRITEPAGE_ACTIVATE to userland |
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On Mon, 15 Oct 2007, Pekka Enberg wrote: > > I wonder whether _not setting_ BDI_CAP_NO_WRITEBACK implies that > ->writepage() will never return AOP_WRITEPAGE_ACTIVATE for > !wbc->for_reclaim case which would explain why we haven't hit this bug > before. Hugh, Andrew?
Only ramdisk and shmem have been returning AOP_WRITEPAGE_ACTIVATE. Both of those set BDI_CAP_NO_WRITEBACK. ramdisk never returned it if !wbc->for_reclaim. I contend that shmem shouldn't either: it's a special code to get the LRU rotation right, not useful elsewhere. Though Documentation/filesystems/vfs.txt does imply wider use.
I think this is where people use the phrase "go figure" ;)
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