On Wed, 2007-08-22 at 11:52 +0900, KAMEZAWA Hiroyuki wrote:
> On Wed, 22 Aug 2007 10:08:09 +0800
> Shaohua Li <[email protected]> wrote:
>
> > commit dc386d4d1e98bb39fb967ee156cd456c802fc692 adds rcu_read_lock, but
> > some routines in the lock range might sleep (like lock_buffer,
> > aops->writepage), I saw a 'sleep in atomic' warning. It appears the
> > patch has several versions before. Doing rcu_read_lock in PageAnon
> > sounds break the case of PageAnon(page) && PageSwapCache(page),
> > as .writepage might be called. The dummy anon patch maybe is ok.
> >
>
> Thank you for catching.
>
> Maybe you're correct.
>
> BTW, in PageAnon(page) && PageSwapCache(page) case, I can't find when
> .writepage is called. Could you explain ?
>
> In my understanding,
>
> rcu_read_lock()
> -> try_to_unmap()
> -> move_to_new_page()
> -> migrate_page() // swap has .migratepage member.
> -> migrate_page_move_mapping().
> -> migrate_page_copy().
> -> remove_migration_ptes().
>
>
> At quick glance, above path has no writepage() ops.
> just replace swap's radix tree entry.
I missed swap has .migratepage and thought fallback_migrate_page is
used, then I thought doing rcu lock in PageAnon case is ok.
Thanks,
Shaohua
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
