Hi,
On Thu, 2004-04-01 at 17:19, Jamie Lokier wrote:
> Some documentation I'm looking at says MS_INVALIDATE updates the
> mapped page to contain the current contents of the file. 2.6.4 seems
> to do the reverse: update the file to contain the current content of
> the mapped page. "man msync" agrees with the the latter. (I can't
> look at SUS right now).
btw, just looking at the filemap_sync_pte() code for MS_INVALIDATE, I
noticed
if (!PageReserved(page) &&
(ptep_clear_flush_dirty(vma, address, ptep) ||
page_test_and_clear_dirty(page)))
set_page_dirty(page);
I just happened to follow the function and noticed that on s390,
page_test_and_clear_dirty() has the comment:
* Test and clear dirty bit in storage key.
* We can't clear the changed bit atomically. This is a potential
* race against modification of the referenced bit. This function
* should therefore only be called if it is not mapped in any
* address space.
but in this case the page is clearly mapped in the caller's address
space, else we wouldn't have reached this.
Is this a problem?
--Stephen
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