| Message ID | 1453929472-25566-6-git-send-email-matthew.r.wilcox@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Jan 28, 2016 at 12:17 AM, Matthew Wilcox <matthew.r.wilcox@intel.com> wrote: > From: Matthew Wilcox <willy@linux.intel.com> > > shmem likes to occasionally drop the lock, schedule, then reacqire > the lock and continue with the iteration from the last place it > left off. This is currently done with a pretty ugly goto. Introduce > radix_tree_iter_next() and use it throughout shmem.c. > > Signed-off-by: Matthew Wilcox <willy@linux.intel.com> > --- > include/linux/radix-tree.h | 15 +++++++++++++++ > mm/shmem.c | 12 +++--------- > 2 files changed, 18 insertions(+), 9 deletions(-) > > diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h > index db0ed595749b..dec2c6c77eea 100644 > --- a/include/linux/radix-tree.h > +++ b/include/linux/radix-tree.h > @@ -403,6 +403,21 @@ void **radix_tree_iter_retry(struct radix_tree_iter *iter) > } > > /** > + * radix_tree_iter_next - resume iterating when the chunk may be invalid > + * @iter: iterator state > + * > + * If the iterator needs to release then reacquire a lock, the chunk may > + * have been invalidated by an insertion or deletion. Call this function > + * to continue the iteration from the next index. > + */ > +static inline __must_check > +void **radix_tree_iter_next(struct radix_tree_iter *iter) > +{ > + iter->next_index = iter->index + 1; > + return NULL; > +} > + > +/** This works for normal iterator but not for tagged. It must also reset iter->tags to zero. > * radix_tree_chunk_size - get current chunk size > * > * @iter: pointer to radix tree iterator > diff --git a/mm/shmem.c b/mm/shmem.c > index 6ec14b70d82d..438ea8004c26 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -376,7 +376,6 @@ unsigned long shmem_partial_swap_usage(struct address_space *mapping, > > rcu_read_lock(); > > -restart: > radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { > if (iter.index >= end) > break; > @@ -398,8 +397,7 @@ restart: > > if (need_resched()) { > cond_resched_rcu(); > - start = iter.index + 1; > - goto restart; > + slot = radix_tree_iter_next(&iter); > } > } > > @@ -1950,7 +1948,6 @@ static void shmem_tag_pins(struct address_space *mapping) > start = 0; > rcu_read_lock(); > > -restart: > radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { > page = radix_tree_deref_slot(slot); > if (!page || radix_tree_exception(page)) { > @@ -1967,8 +1964,7 @@ restart: > > if (need_resched()) { > cond_resched_rcu(); > - start = iter.index + 1; > - goto restart; > + slot = radix_tree_iter_next(&iter); > } > } > rcu_read_unlock(); > @@ -2005,7 +2001,6 @@ static int shmem_wait_for_pins(struct address_space *mapping) > > start = 0; > rcu_read_lock(); > -restart: > radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, > start, SHMEM_TAG_PINNED) { > > @@ -2039,8 +2034,7 @@ restart: > continue_resched: > if (need_resched()) { > cond_resched_rcu(); > - start = iter.index + 1; > - goto restart; > + slot = radix_tree_iter_next(&iter); > } > } > rcu_read_unlock(); > -- > 2.7.0.rc3 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index db0ed595749b..dec2c6c77eea 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -403,6 +403,21 @@ void **radix_tree_iter_retry(struct radix_tree_iter *iter) } /** + * radix_tree_iter_next - resume iterating when the chunk may be invalid + * @iter: iterator state + * + * If the iterator needs to release then reacquire a lock, the chunk may + * have been invalidated by an insertion or deletion. Call this function + * to continue the iteration from the next index. + */ +static inline __must_check +void **radix_tree_iter_next(struct radix_tree_iter *iter) +{ + iter->next_index = iter->index + 1; + return NULL; +} + +/** * radix_tree_chunk_size - get current chunk size * * @iter: pointer to radix tree iterator diff --git a/mm/shmem.c b/mm/shmem.c index 6ec14b70d82d..438ea8004c26 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -376,7 +376,6 @@ unsigned long shmem_partial_swap_usage(struct address_space *mapping, rcu_read_lock(); -restart: radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { if (iter.index >= end) break; @@ -398,8 +397,7 @@ restart: if (need_resched()) { cond_resched_rcu(); - start = iter.index + 1; - goto restart; + slot = radix_tree_iter_next(&iter); } } @@ -1950,7 +1948,6 @@ static void shmem_tag_pins(struct address_space *mapping) start = 0; rcu_read_lock(); -restart: radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { page = radix_tree_deref_slot(slot); if (!page || radix_tree_exception(page)) { @@ -1967,8 +1964,7 @@ restart: if (need_resched()) { cond_resched_rcu(); - start = iter.index + 1; - goto restart; + slot = radix_tree_iter_next(&iter); } } rcu_read_unlock(); @@ -2005,7 +2001,6 @@ static int shmem_wait_for_pins(struct address_space *mapping) start = 0; rcu_read_lock(); -restart: radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, start, SHMEM_TAG_PINNED) { @@ -2039,8 +2034,7 @@ restart: continue_resched: if (need_resched()) { cond_resched_rcu(); - start = iter.index + 1; - goto restart; + slot = radix_tree_iter_next(&iter); } } rcu_read_unlock();