2019-08-02 09:38:03

by Joonas Lahtinen

[permalink] [raw]
Subject: Re: [PATCH 06/34] drm/i915: convert put_page() to put_user_page*()

Quoting [email protected] (2019-08-02 05:19:37)
> From: John Hubbard <[email protected]>
>
> For pages that were retained via get_user_pages*(), release those pages
> via the new put_user_page*() routines, instead of via put_page() or
> release_pages().
>
> This is part a tree-wide conversion, as described in commit fc1d8e7cca2d
> ("mm: introduce put_user_page*(), placeholder versions").
>
> Note that this effectively changes the code's behavior in
> i915_gem_userptr_put_pages(): it now calls set_page_dirty_lock(),
> instead of set_page_dirty(). This is probably more accurate.

We've already fixed this in drm-tip where the current code uses
set_page_dirty_lock().

This would conflict with our tree. Rodrigo is handling
drm-intel-next for 5.4, so you guys want to coordinate how
to merge.

Regards, Joonas


2019-08-03 16:57:40

by John Hubbard

[permalink] [raw]
Subject: Re: [PATCH 06/34] drm/i915: convert put_page() to put_user_page*()

On 8/2/19 2:19 AM, Joonas Lahtinen wrote:
> Quoting [email protected] (2019-08-02 05:19:37)
>> From: John Hubbard <[email protected]>
>>
>> For pages that were retained via get_user_pages*(), release those pages
>> via the new put_user_page*() routines, instead of via put_page() or
>> release_pages().
>>
>> This is part a tree-wide conversion, as described in commit fc1d8e7cca2d
>> ("mm: introduce put_user_page*(), placeholder versions").
>>
>> Note that this effectively changes the code's behavior in
>> i915_gem_userptr_put_pages(): it now calls set_page_dirty_lock(),
>> instead of set_page_dirty(). This is probably more accurate.
>
> We've already fixed this in drm-tip where the current code uses
> set_page_dirty_lock().
>
> This would conflict with our tree. Rodrigo is handling
> drm-intel-next for 5.4, so you guys want to coordinate how
> to merge.
>

Hi Joonas, Rodrigo,

First of all, I apologize for the API breakage: put_user_pages_dirty_lock()
has an additional "dirty" parameter.

In order to deal with the merge problem, I'll drop this patch from my series,
and I'd recommend that the drm-intel-next take the following approach:

1) For now, s/put_page/put_user_page/ in i915_gem_userptr_put_pages(),
and fix up the set_page_dirty() --> set_page_dirty_lock() issue, like this
(based against linux.git):

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index 528b61678334..94721cc0093b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -664,10 +664,10 @@ i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj,

for_each_sgt_page(page, sgt_iter, pages) {
if (obj->mm.dirty)
- set_page_dirty(page);
+ set_page_dirty_lock(page);

mark_page_accessed(page);
- put_page(page);
+ put_user_page(page);
}
obj->mm.dirty = false;


That will leave you with your original set_page_dirty_lock() calls
and everything works properly.

2) Next cycle, move to the new put_user_pages_dirty_lock().

thanks,
--
John Hubbard
NVIDIA


> Regards, Joonas
>

2019-08-04 04:02:13

by John Hubbard

[permalink] [raw]
Subject: Re: [PATCH 06/34] drm/i915: convert put_page() to put_user_page*()

On 8/2/19 11:48 AM, John Hubbard wrote:
> On 8/2/19 2:19 AM, Joonas Lahtinen wrote:
>> Quoting [email protected] (2019-08-02 05:19:37)
>>> From: John Hubbard <[email protected]>
...
> In order to deal with the merge problem, I'll drop this patch from my series,
> and I'd recommend that the drm-intel-next take the following approach:

Actually, I just pulled the latest linux.git, and there are a few changes:

>
> 1) For now, s/put_page/put_user_page/ in i915_gem_userptr_put_pages(),
> and fix up the set_page_dirty() --> set_page_dirty_lock() issue, like this
> (based against linux.git):
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
> index 528b61678334..94721cc0093b 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
> @@ -664,10 +664,10 @@ i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj,
>
>         for_each_sgt_page(page, sgt_iter, pages) {
>                 if (obj->mm.dirty)
> -                       set_page_dirty(page);
> +                       set_page_dirty_lock(page);

I see you've already applied this fix to your tree, in linux.git already.

>
>                 mark_page_accessed(page);
> -               put_page(page);
> +               put_user_page(page);

But this conversion still needs doing. So I'll repost a patch that only does
this (plus the other call sites).

That can go in via either your tree, or Andrew's -mm tree, without generating
any conflicts.

thanks,
--
John Hubbard
NVIDIA