Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 8 Oct 2003 07:57:00 -0700 | From | "David S. Miller" <> | Subject | Re: [PATCH] page->flags corruption fix |
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On Wed, 8 Oct 2003 15:49:34 +0100 (BST) Hugh Dickins <hugh@veritas.com> wrote:
> Seven atomic ops in a row, isn't that rather inefficient? > The 2.6 version clears those PG_flags all together in one > non-atomic op - but elsewhere, in prep_new_page. > > Is there an actual test case for why 2.4 now needs this change?
It's not a new bug, we've always had this bug in 2.4.x
There is so much code that does atomic bit ops asynchronously on page->flags that it is therefore not safe for any context to make non-atomic changes to the values there.
The patch Rik posted is the safest solution to this bug. If you want to make it faster by creating a "mutliple bit" set of bitops go right ahead, but be nice enough to make sure every single architecture has an implementation before suggesting that the change gets merged into 2.4.x - 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/
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