lkml.org 
[lkml]   [2007]   [Feb]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [rfc][patch 0/3] a faster buffered write deadlock fix?
    On Fri, Feb 09, 2007 at 02:09:54AM -0800, Andrew Morton wrote:
    > On Fri, 9 Feb 2007 10:54:05 +0100 Nick Piggin <npiggin@suse.de> wrote:
    >
    > >
    > > That's still got a deadlock,
    >
    > It does?

    Yes, PG_lock vs mm->mmap_sem.

    > > and also it doesn't work if we want to lock
    > > the page when performing a minor fault (which I want to fix fault vs
    > > invalidate),
    >
    > It's hard to discuss this without a description of what you want to fix
    > there, and a description of how you plan to fix it.

    http://marc.theaimsgroup.com/?l=linux-mm&m=116865911432667&w=2

    > > and also assumes nobody's ->nopage locks the page or
    > > requires any resources that are held by prepare_write (something not
    > > immediately clear to me with the cluster filesystems, at least).
    >
    > The nopage handler is filemap_nopage(). Are there any exceptions to that?

    OCFS2 and GFS2.

    > > But that all becomes legacy path, so do we really care? Supposing fs
    > > maintainers like perform_write, then after the main ones have implementations
    > > we could switch over to the slow-but-correct prepare_write legacy path.
    > > Or we could leave it, or we could use Linus's slightly-less-buggy scheme...
    > > by that point I expect I'd be sick of arguing about it ;)
    >
    > It's worth "arguing" about. This is write(). What matters more??

    That's the legacy path that uses prepare/commit (ie. supposing that all
    major filesystems did get converted to perform_write).

    Of course I would still want my correct-but-slow version in that case,
    but I just wouldn't care to argue if you still wanted to keep it fast.

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2007-02-09 11:35    [W:3.336 / U:0.316 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site