Messages in this thread | | | Date | Sun, 12 Feb 2006 23:59:06 -0800 (PST) | Subject | Re: [PATCH 1/3] compound page: use page[1].lru | From | "David S. Miller" <> |
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From: Andrew Morton <akpm@osdl.org> Date: Sun, 12 Feb 2006 23:12:23 -0800
> "David S. Miller" <davem@davemloft.net> wrote: > > > > The ->mapping check is there essentially to hit user mapped pages that > > would be modified by the kernel using kernel space memory accesses > > other than those done by copy_user_page() and clear_user_page() (and > > their brothers copy_user_highpage() and clear_user_highpage() which > > just call the former directly on a non-HIGHPAGE platform like > > sparc64). > > The direct-io.c code just does memset. (That's very common - maybe > clear_user_highpage_partial() is needed?)
Yes, something like clear_user_higpage_partial() is definitely needed for cases like direct-io.c.
We have similar handling for when ptrace() uses get_user_pages() and tries to write to those pages, via copy_to_user_page() and copy_from_user_page(). But those interfaces don't clear memory and they only work in the ptrace path, and they are optimized for that usage. - 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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