In zap_pte_range(), the check for non_swap_entry() and
is_device_private_entry() is redundant since the latter is a subset of the
former. Remove the redundant check to simplify the code and for clarity.
Signed-off-by: Ralph Campbell <[email protected]>
---
This is based on the current linux tree and is intended for Andrew's mm
tree. There is no rush so it could go into 5.9 but I think it is safe
enough to go into an rc after the patch is reviewed.
mm/memory.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/memory.c b/mm/memory.c
index dc7f3543b1fd..bdbb4f97e7d0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1098,7 +1098,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
}
entry = pte_to_swp_entry(ptent);
- if (non_swap_entry(entry) && is_device_private_entry(entry)) {
+ if (is_device_private_entry(entry)) {
struct page *page = device_private_entry_to_page(entry);
if (unlikely(details && details->check_mapping)) {
--
2.20.1
On Fri, Jun 12, 2020 at 12:26:18PM -0700, Ralph Campbell wrote:
> In zap_pte_range(), the check for non_swap_entry() and
> is_device_private_entry() is redundant since the latter is a subset of the
> former. Remove the redundant check to simplify the code and for clarity.
That is highly configuration dependent.
#else /* CONFIG_DEVICE_PRIVATE */
...
static inline bool is_device_private_entry(swp_entry_t entry)
{
return false;
}
...
#if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) || \
defined(CONFIG_DEVICE_PRIVATE)
static inline int non_swap_entry(swp_entry_t entry)
{
return swp_type(entry) >= MAX_SWAPFILES;
}
#else
static inline int non_swap_entry(swp_entry_t entry)
{
return 0;
}
#endif
On Fri, Jun 12, 2020 at 12:26:18PM -0700, Ralph Campbell wrote:
> In zap_pte_range(), the check for non_swap_entry() and
> is_device_private_entry() is redundant since the latter is a subset of the
> former. Remove the redundant check to simplify the code and for clarity.
>
> Signed-off-by: Ralph Campbell <[email protected]>
>
> This is based on the current linux tree and is intended for Andrew's mm
> tree. There is no rush so it could go into 5.9 but I think it is safe
> enough to go into an rc after the patch is reviewed.
Probably shouldn't mark it as mm/hmm if Andrew is going to pick it
Reviewed-by: Jason Gunthorpe <[email protected]>
Jason
On Fri, Jun 12, 2020 at 12:35:24PM -0700, Matthew Wilcox wrote:
> On Fri, Jun 12, 2020 at 12:26:18PM -0700, Ralph Campbell wrote:
> > In zap_pte_range(), the check for non_swap_entry() and
> > is_device_private_entry() is redundant since the latter is a subset of the
> > former. Remove the redundant check to simplify the code and for clarity.
>
> That is highly configuration dependent.
>
> #else /* CONFIG_DEVICE_PRIVATE */
> ...
> static inline bool is_device_private_entry(swp_entry_t entry)
> {
> return false;
> }
The commit message might be a bit confusing, as it is not a subset, I
would say that device_private_entry alone is sufficient to tell if the
entry is private or not.
For the !CONFIG_DEVICE_PRIVATE case having it wired to false is
right.
Jason
On 6/12/20 12:33 PM, Jason Gunthorpe wrote:
> On Fri, Jun 12, 2020 at 12:26:18PM -0700, Ralph Campbell wrote:
>> In zap_pte_range(), the check for non_swap_entry() and
>> is_device_private_entry() is redundant since the latter is a subset of the
>> former. Remove the redundant check to simplify the code and for clarity.
>>
>> Signed-off-by: Ralph Campbell <[email protected]>
>>
>> This is based on the current linux tree and is intended for Andrew's mm
>> tree. There is no rush so it could go into 5.9 but I think it is safe
>> enough to go into an rc after the patch is reviewed.
>
> Probably shouldn't mark it as mm/hmm if Andrew is going to pick it
OK, I'll mark it as just mm: if I need to repost.
> Reviewed-by: Jason Gunthorpe <[email protected]>
>
> Jason
>
Thanks!
On 6/12/20 12:42 PM, Jason Gunthorpe wrote:
> On Fri, Jun 12, 2020 at 12:35:24PM -0700, Matthew Wilcox wrote:
>> On Fri, Jun 12, 2020 at 12:26:18PM -0700, Ralph Campbell wrote:
>>> In zap_pte_range(), the check for non_swap_entry() and
>>> is_device_private_entry() is redundant since the latter is a subset of the
>>> former. Remove the redundant check to simplify the code and for clarity.
>>
>> That is highly configuration dependent.
>>
>> #else /* CONFIG_DEVICE_PRIVATE */
>> ...
>> static inline bool is_device_private_entry(swp_entry_t entry)
>> {
>> return false;
>> }
>
> The commit message might be a bit confusing, as it is not a subset, I
> would say that device_private_entry alone is sufficient to tell if the
> entry is private or not.
>
> For the !CONFIG_DEVICE_PRIVATE case having it wired to false is
> right.
>
> Jason
>
How about the following message instead?
In zap_pte_range(), the check for non_swap_entry() and
is_device_private_entry() is unnecessary since the latter is sufficient
to determine if the page is a device private page. Remove the test for
non_swap_entry() to simplify the code and for clarity.
On Fri, Jun 12, 2020 at 12:53:23PM -0700, Ralph Campbell wrote:
>
> On 6/12/20 12:42 PM, Jason Gunthorpe wrote:
> > On Fri, Jun 12, 2020 at 12:35:24PM -0700, Matthew Wilcox wrote:
> > > On Fri, Jun 12, 2020 at 12:26:18PM -0700, Ralph Campbell wrote:
> > > > In zap_pte_range(), the check for non_swap_entry() and
> > > > is_device_private_entry() is redundant since the latter is a subset of the
> > > > former. Remove the redundant check to simplify the code and for clarity.
> > >
> > > That is highly configuration dependent.
> > >
> > > #else /* CONFIG_DEVICE_PRIVATE */
> > > ...
> > > static inline bool is_device_private_entry(swp_entry_t entry)
> > > {
> > > return false;
> > > }
> >
> > The commit message might be a bit confusing, as it is not a subset, I
> > would say that device_private_entry alone is sufficient to tell if the
> > entry is private or not.
> >
> > For the !CONFIG_DEVICE_PRIVATE case having it wired to false is
> > right.
> >
> > Jason
> >
>
> How about the following message instead?
>
> In zap_pte_range(), the check for non_swap_entry() and
> is_device_private_entry() is unnecessary since the latter is sufficient
> to determine if the page is a device private page. Remove the test for
> non_swap_entry() to simplify the code and for clarity.
Yes, that is clearer to me
Jason