Messages in this thread | | | Date | Sat, 02 Feb 2013 12:25:44 +0400 | From | Konstantin Khlebnikov <> | Subject | Re: [patch] mm: shmem: use new radix tree iterator |
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Johannes Weiner wrote: > In shmem_find_get_pages_and_swap, use the faster radix tree iterator > construct from 78c1d78 "radix-tree: introduce bit-optimized iterator". > > Signed-off-by: Johannes Weiner<hannes@cmpxchg.org>
Hmm, ACK. shmem_unuse_inode() also can be redone in this way. I did something similar year ago: https://lkml.org/lkml/2012/2/10/388 As result we can rid of radix_tree_locate_item() and shmem_find_get_pages_and_swap()
> --- > mm/shmem.c | 25 ++++++++++++------------- > 1 file changed, 12 insertions(+), 13 deletions(-) > > diff --git a/mm/shmem.c b/mm/shmem.c > index a368a1c..c5dc8ae 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -336,19 +336,19 @@ static unsigned shmem_find_get_pages_and_swap(struct address_space *mapping, > pgoff_t start, unsigned int nr_pages, > struct page **pages, pgoff_t *indices) > { > - unsigned int i; > - unsigned int ret; > - unsigned int nr_found; > + void **slot; > + unsigned int ret = 0; > + struct radix_tree_iter iter; > + > + if (!nr_pages) > + return 0; > > rcu_read_lock(); > restart: > - nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree, > - (void ***)pages, indices, start, nr_pages); > - ret = 0; > - for (i = 0; i< nr_found; i++) { > + radix_tree_for_each_slot(slot,&mapping->page_tree,&iter, start) { > struct page *page; > repeat: > - page = radix_tree_deref_slot((void **)pages[i]); > + page = radix_tree_deref_slot(slot); > if (unlikely(!page)) > continue; > if (radix_tree_exception(page)) { > @@ -365,17 +365,16 @@ static unsigned shmem_find_get_pages_and_swap(struct address_space *mapping, > goto repeat; > > /* Has the page moved? */ > - if (unlikely(page != *((void **)pages[i]))) { > + if (unlikely(page != *slot)) { > page_cache_release(page); > goto repeat; > } > export: > - indices[ret] = indices[i]; > + indices[ret] = iter.index; > pages[ret] = page; > - ret++; > + if (++ret == nr_pages) > + break; > } > - if (unlikely(!ret&& nr_found)) > - goto restart; > rcu_read_unlock(); > return ret; > }
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