diff mbox series

[v4,2/2] mm: swap: add comment for swap_vma_readahead

Message ID 1546145375-793-2-git-send-email-yang.shi@linux.alibaba.com (mailing list archive)
State New, archived
Headers show
Series [v4,1/2] mm: swap: check if swap backing device is congested or not | expand

Commit Message

Yang Shi Dec. 30, 2018, 4:49 a.m. UTC
swap_vma_readahead()'s comment is missed, just add it.

Cc: Huang Ying <ying.huang@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
---
 mm/swap_state.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

Comments

Huang, Ying Jan. 3, 2019, 7:41 a.m. UTC | #1
Yang Shi <yang.shi@linux.alibaba.com> writes:

> swap_vma_readahead()'s comment is missed, just add it.
>
> Cc: Huang Ying <ying.huang@intel.com>
> Cc: Tim Chen <tim.c.chen@intel.com>
> Cc: Minchan Kim <minchan@kernel.org>
> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
> ---
>  mm/swap_state.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
>
> diff --git a/mm/swap_state.c b/mm/swap_state.c
> index 78d500e..dd8f698 100644
> --- a/mm/swap_state.c
> +++ b/mm/swap_state.c
> @@ -698,6 +698,23 @@ static void swap_ra_info(struct vm_fault *vmf,
>  	pte_unmap(orig_pte);
>  }
>  
> +/**
> + * swap_vm_readahead - swap in pages in hope we need them soon

s/swap_vm_readahead/swap_vma_readahead/

> + * @entry: swap entry of this memory
> + * @gfp_mask: memory allocation flags
> + * @vmf: fault information
> + *
> + * Returns the struct page for entry and addr, after queueing swapin.
> + *
> + * Primitive swap readahead code. We simply read in a few pages whoes
> + * virtual addresses are around the fault address in the same vma.
> + *
> + * This has been extended to use the NUMA policies from the mm triggering
> + * the readahead.

What is this?  I know you copy it from swap_cluster_readahead(), but we
have only one mm for vma readahead.

> + * Caller must hold down_read on the vma->vm_mm if vmf->vma is not NULL.

Better to make it explicit that your are talking about mmap_sem?

Best Regards,
Huang, Ying

> + *
> + */
>  static struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask,
>  				       struct vm_fault *vmf)
>  {
Yang Shi Jan. 3, 2019, 5:12 p.m. UTC | #2
On 1/2/19 11:41 PM, Huang, Ying wrote:
> Yang Shi <yang.shi@linux.alibaba.com> writes:
>
>> swap_vma_readahead()'s comment is missed, just add it.
>>
>> Cc: Huang Ying <ying.huang@intel.com>
>> Cc: Tim Chen <tim.c.chen@intel.com>
>> Cc: Minchan Kim <minchan@kernel.org>
>> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
>> ---
>>   mm/swap_state.c | 17 +++++++++++++++++
>>   1 file changed, 17 insertions(+)
>>
>> diff --git a/mm/swap_state.c b/mm/swap_state.c
>> index 78d500e..dd8f698 100644
>> --- a/mm/swap_state.c
>> +++ b/mm/swap_state.c
>> @@ -698,6 +698,23 @@ static void swap_ra_info(struct vm_fault *vmf,
>>   	pte_unmap(orig_pte);
>>   }
>>   
>> +/**
>> + * swap_vm_readahead - swap in pages in hope we need them soon
> s/swap_vm_readahead/swap_vma_readahead/
>
>> + * @entry: swap entry of this memory
>> + * @gfp_mask: memory allocation flags
>> + * @vmf: fault information
>> + *
>> + * Returns the struct page for entry and addr, after queueing swapin.
>> + *
>> + * Primitive swap readahead code. We simply read in a few pages whoes
>> + * virtual addresses are around the fault address in the same vma.
>> + *
>> + * This has been extended to use the NUMA policies from the mm triggering
>> + * the readahead.
> What is this?  I know you copy it from swap_cluster_readahead(), but we
> have only one mm for vma readahead.

Aha, I see. Actually I was confused by this too, so just copied from 
swap_cluster_readahead.

>
>> + * Caller must hold down_read on the vma->vm_mm if vmf->vma is not NULL.
> Better to make it explicit that your are talking about mmap_sem?

Sure.

Thanks,
Yang

>
> Best Regards,
> Huang, Ying
>
>> + *
>> + */
>>   static struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask,
>>   				       struct vm_fault *vmf)
>>   {
diff mbox series

Patch

diff --git a/mm/swap_state.c b/mm/swap_state.c
index 78d500e..dd8f698 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -698,6 +698,23 @@  static void swap_ra_info(struct vm_fault *vmf,
 	pte_unmap(orig_pte);
 }
 
+/**
+ * swap_vm_readahead - swap in pages in hope we need them soon
+ * @entry: swap entry of this memory
+ * @gfp_mask: memory allocation flags
+ * @vmf: fault information
+ *
+ * Returns the struct page for entry and addr, after queueing swapin.
+ *
+ * Primitive swap readahead code. We simply read in a few pages whoes
+ * virtual addresses are around the fault address in the same vma.
+ *
+ * This has been extended to use the NUMA policies from the mm triggering
+ * the readahead.
+ *
+ * Caller must hold down_read on the vma->vm_mm if vmf->vma is not NULL.
+ *
+ */
 static struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask,
 				       struct vm_fault *vmf)
 {