Hello Matthew,
Thanks for your precious answers.
On Thu, Jan 15, 2009 at 3:00 PM, Matthew Wilcox <matthew@xxxxxx> wrote:
> Sure. Take a look in mm/filemap.c. Filesystems that use the page cache
> will usually end up calling do_generic_file_read() one way or another.
> It tries to find the page in the page cache, when it doesn't find the
> page, it creates it, then calls ->readpage() to start the read, and
> lock_page_killable() to wait for the page to be read.
I see now thanks !
> As the comment says, when the read finishes, it will unlock the page
> and the reader will continue.
I expect that the comment you're talking about is this one in
do_generic_file_read():
page_not_up_to_date:
/* Get exclusive access to the page ... */
error = lock_page_killable(page);
if (unlikely(error))
goto readpage_error;
If so, IMHO it's pretty useless as is... it could have been:
/* we're probably going to wait for the data to be ready */
or something.
--
Francis
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