Messages in this thread | | | Subject | Re: [PATCH -v6 2/2] Updating ctime and mtime for memory-mapped files | From | Miklos Szeredi <> | Date | Fri, 18 Jan 2008 19:57:17 +0100 |
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> > That would need a new page flag (PG_mmap_dirty?). Do we have one > > available? > > Yeah, that would be bad. We probably have flags free, but those page flags > are always a pain. Scratch that. > > How about just setting a per-vma dirty flag, and then instead of updating > the mtime when taking the dirty-page fault, we just set that flag? > > Then, on unmap and msync, we just do > > if (vma->dirty-flag) { > vma->dirty_flag = 0; > update_file_times(vma->vm_file); > } > > and be done with it?
But then background writeout, sync(2), etc, wouldn't update the times. Dunno. I don't think actual _physical_ writeout matters much, so it's not worse to be 30s early with the timestamp, than to be 30s or more late.
Miklos
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