Messages in this thread |  | | Subject | Re: [PATCHv2 4/8] khugepaged: Drain LRU add pagevec after swapin | From | Yang Shi <> | Date | Mon, 6 Apr 2020 11:29:11 -0700 |
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On 4/3/20 4:29 AM, Kirill A. Shutemov wrote: > __collapse_huge_page_isolate() may fail due to extra pin in the LRU add > pagevec. It's petty common for swapin case: we swap in pages just to > fail due to the extra pin. > > Drain LRU add pagevec on sucessfull swapin. > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > --- > mm/khugepaged.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index fdc10ffde1ca..57ff287caf6b 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -940,6 +940,11 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm, > } > vmf.pte--; > pte_unmap(vmf.pte); > + > + /* Drain LRU add pagevec to remove extra pin on the swapped in pages */ > + if (swapped_in) > + lru_add_drain();
There is already lru_add_drain() called in swap readahead path, please see swap_vma_readahead() and swap_cluster_readahead().
The extra call to draining lru seems unnecessary.
> + > trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 1); > return true; > }
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