Hi,
On Wed, Dec 11, 2002 at 09:01:02AM +0100, Jan Hudec wrote:
> > What is the meaning of this dirty queue, what is the effect of linking
> > a page onto that queue, and when should the set_page_dirty() function
> > be used rather than the
> > SetPageDirty() macro?
>
> If you use the SetPageDirty macro, then the page is marked dirty, but
> kernel can't find it when it should clean it. Thus it eventualy won't
> flush the data (it won't call writepage on it).
set_page_dirty() can be used in all cases, IMHO, since it:
- will not sleep
- will not call the set_page_dirty() method, if page has been dirty
before (test_and_set_XXX is atomic an guarantees to trigger
once only)
- will not do anything besides settingt the PG_Dirty bit,
if the page contains no mapping, or does not contain a
set_page_dirty_method
So if set_page_dirty() exists on a certain kernel you want to
support, it should be used in all cases. Accounting code can also
be hooked into this, if it is used properly.
Regards
Ingo Oeser
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