On Fri, Aug 14, 2020 at 5:26 PM Hugh Dickins wrote:
>
> We used to rely on page count there, and on trylock_page() only; but
> there was at least one user whose app went wrong when occasionally we
> COWed the page, just because something else momentarily took a reference
> to it, or locked it.
On Fri, 14 Aug 2020, Linus Torvalds wrote:
> On Thu, Aug 13, 2020 at 10:42 PM Christoph Hellwig wrote:
> >
> > The whole thing predates my involvement with the code, but I defintively
> > think the patch from Hugh is a major improvement. But I would also
> > have no problem with just removing it
On Thu, Aug 13, 2020 at 10:42 PM Christoph Hellwig wrote:
>
> The whole thing predates my involvement with the code, but I defintively
> think the patch from Hugh is a major improvement. But I would also
> have no problem with just removing it entirely.
I decided to just do both, since neither
On Thu, Aug 13, 2020 at 12:02:41PM -0700, Linus Torvalds wrote:
> Yeah, that's ridiculously expensive, and serializes things for no good reason.
>
> Your patch looks obviously correct to me (Christoph?),
It also looks correct to me.
> but it also
> makes me go "why are we doing this in the
On Thu, Aug 13, 2020 at 12:03 PM Linus Torvalds
wrote:
>
> On Wed, Aug 12, 2020 at 8:17 PM Hugh Dickins wrote:
> >
> > Since commit 2a9127fcf229 ("mm: rewrite wait_on_page_bit_common() logic")
> > improved unlock_page(), it has become more noticeable how cow_user_page()
> > in a kernel with
On Wed, Aug 12, 2020 at 8:17 PM Hugh Dickins wrote:
>
> Since commit 2a9127fcf229 ("mm: rewrite wait_on_page_bit_common() logic")
> improved unlock_page(), it has become more noticeable how cow_user_page()
> in a kernel with CONFIG_DMA_API_DEBUG=y can create and suffer from heavy
> contention on
Since commit 2a9127fcf229 ("mm: rewrite wait_on_page_bit_common() logic")
improved unlock_page(), it has become more noticeable how cow_user_page()
in a kernel with CONFIG_DMA_API_DEBUG=y can create and suffer from heavy
contention on DMA debug's radix_lock in debug_dma_assert_idle().
It is only
7 matches
Mail list logo