Re: [Xen-devel] [PATCH v1 2/9] mm: Place unscrubbed pages at the end of pagelist

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

On 03/28/2017 03:27 PM, Wei Liu wrote:
> On Fri, Mar 24, 2017 at 01:04:57PM -0400, Boris Ostrovsky wrote:
>> . so that it's easy to find pages that need to be scrubbed (those pages are
>> now marked with _PGC_need_scrub bit).
> s/bool_t/bool/ throughout and use true and false where appropriate.
>
>>  
>>  /* Free 2^@order set of pages. */
>>  static void free_heap_pages(
>> -    struct page_info *pg, unsigned int order)
>> +    struct page_info *pg, unsigned int order, bool_t need_scrub)
>>  {
>>      unsigned long mfn = page_to_mfn(pg);
>>      unsigned int i, node = phys_to_nid(page_to_maddr(pg)), tainted = 0;
>> @@ -1025,11 +1086,20 @@ static void free_heap_pages(
>>          midsize_alloc_zone_pages = max(
>>              midsize_alloc_zone_pages, total_avail_pages / 
>> MIDSIZE_ALLOC_FRAC);
>>  
>> +    if ( need_scrub && !tainted )
>> +    {
>> +        pg->count_info |= PGC_need_scrub;
>> +        node_need_scrub[node] += (1UL << order);
>> +    }
>> +
> I think this is wrong: you shouldn't have !tainted here, otherwise
> reserve_offlined_page won't know the page needs to be scrubbed,
> resulting in all sub-pages not marked as needing scrub.

Right. This looks like a leftover from an earlier version of this series
and I never removed !tainted test.

-boris

>>      merge_chunks(pg, node, zone, order);
>>  
>>      if ( tainted )
>>          reserve_offlined_page(pg);
>>  
>> +    if ( need_scrub )
>> +        scrub_free_pages(node);
>> +
>>      spin_unlock(&heap_lock);
>>  }
> Wei.


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