On 5/1/07, Nate Diller <[email protected]> wrote:
On 5/1/07, Christoph Lameter <[email protected]> wrote:
> On Tue, 1 May 2007, Andrew Morton wrote:
>
> > As Satyam said, this will sometimes cause us to map and unmap the page
> > twice, and to run flush_dcache_page() twice. In not-terribly-uncommon
> > circumstances in very frequently called functions.
> >
> > Doesn't seem worth it to me.
>
> Ok but we have that code three times. Should I add a variant of
> zero_user_page that zeroes everything but the section specified?
>
> zero_user_page_allbut() ?
the function already exists, it's called simple_prepare_write(), and i
thought there were patches to convert those callsites in -mm ...
although it looks like i let a review comment on that slide by. I
need to redo a bunch of patches for re-submission anyway, so i guess
i'll deal with that tomorrow.
NATE
well, leave it to me to reply too quickly, sorry. i think we should
leave simple_prepare_write() the way it is, since it's a library
function itself. the other two callsites in your patch are buffers,
which may themselves be smaller than a page so you would need a
special function for just those two uses, there's no other way to
avoid making two calls to flush_dcache_page(). if it's tremendously
important to you to eliminate open coding of these, maybe make a
'static int buffer_prepare_write()' or some such in fs/buffer.c
NATE
-
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]
