On Wed, Mar 23, 2016 at 11:39:44AM +0530, [email protected] wrote:
> +#ifdef CONFIG_MIGRATION
> +static int i915_migratepage(struct address_space *mapping,
> +                         struct page *newpage, struct page *page,
> +                         enum migrate_mode mode, void *dev_priv_data)

If we move this to i915_gem_shrink_migratepage (i.e. i915_gem_shrink),
we can

> +     /*
> +      * Use trylock here, with a timeout, for struct_mutex as
> +      * otherwise there is a possibility of deadlock due to lock
> +      * inversion. This path, which tries to migrate a particular
> +      * page after locking that page, can race with a path which
> +      * truncate/purge pages of the corresponding object (after
> +      * acquiring struct_mutex). Since page truncation will also
> +      * try to lock the page, a scenario of deadlock can arise.
> +      */
> +     while (!mutex_trylock(&dev->struct_mutex) && --timeout)
> +             schedule_timeout_killable(1);

replace this with i915_gem_shrinker_lock() and like constructs with the
other shrinkers. Any reason for dropping the early
if (!page_private(obj)) skip?

Similarly there are other patterns here that would benefit from
integration with existing shrinker logic. However, things like tidying
up the pin_display, unbinding, rpm lock inversion are still only on
list.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre
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