On 07/20/2015 04:21 PM, Kirill A. Shutemov wrote: > Currently we don't split huge page on partial unmap. It's not an ideal > situation. It can lead to memory overhead. > > Furtunately, we can detect partial unmap on page_remove_rmap(). But we > cannot call split_huge_page() from there due to locking context. > > It's also counterproductive to do directly from munmap() codepath: in > many cases we will hit this from exit(2) and splitting the huge page > just to free it up in small pages is not what we really want. > > The patch introduce deferred_split_huge_page() which put the huge page > into queue for splitting. The splitting itself will happen when we get > memory pressure via shrinker interface. The page will be dropped from > list on freeing through compound page destructor. > > Signed-off-by: Kirill A. Shutemov <[email protected]> > Tested-by: Sasha Levin <[email protected]> > Tested-by: Aneesh Kumar K.V <[email protected]> > Acked-by: Vlastimil Babka <[email protected]>
Acked-by: Jerome Marchand <[email protected]> > --- > include/linux/huge_mm.h | 4 ++ > include/linux/mm.h | 2 + > mm/huge_memory.c | 127 > ++++++++++++++++++++++++++++++++++++++++++++++-- > mm/migrate.c | 1 + > mm/page_alloc.c | 2 +- > mm/rmap.c | 7 ++- > 6 files changed, 138 insertions(+), 5 deletions(-) >
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