[PATCH 0/10 v2] Ranged pagevec lookup

[PATCH 0/10 v2] Ranged pagevec lookup

[Jan Kara]

Hello,

This patch series was split out of the larger series to clean up pagevec APIs
and provide ranged lookups. In this series I make pagevec_lookup() update the
index (to be consistent with pagevec_lookup_tag() and also as a preparation
for ranged lookups), provide ranged variant of pagevec_lookup() and use it
in places where it makes sense. This not only removes some common code but
is also a measurable performance win for some use cases (see patch 4/10) where
radix tree is sparse and searching & grabing of a page after the end of the
range has measurable overhead.

Andrew, can you please consider merging this series?

Full series including dependencies can be also obtained from my git tree:

git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git find_get_pages_range

Opinions and review welcome!

								Honza

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[PATCH 01/10] fscache: Remove unused ->now_uncached callback

[Jan Kara]

The callback doesn't ever get called. Remove it.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 Documentation/filesystems/caching/netfs-api.txt |  2 --
 fs/9p/cache.c                                   | 29 -----------------
 fs/afs/cache.c                                  | 43 -------------------------
 fs/ceph/cache.c                                 | 31 ------------------
 fs/cifs/cache.c                                 | 31 ------------------
 fs/nfs/fscache-index.c                          | 40 -----------------------
 include/linux/fscache.h                         |  9 ------
 7 files changed, 185 deletions(-)

diff --git a/Documentation/filesystems/caching/netfs-api.txt b/Documentation/filesystems/caching/netfs-api.txt
index aed6b94160b1..0eb31de3a2c1 100644
--- a/Documentation/filesystems/caching/netfs-api.txt
+++ b/Documentation/filesystems/caching/netfs-api.txt
@@ -151,8 +151,6 @@ To define an object, a structure of the following type should be filled out:
 		void (*mark_pages_cached)(void *cookie_netfs_data,
 					  struct address_space *mapping,
 					  struct pagevec *cached_pvec);
-
-		void (*now_uncached)(void *cookie_netfs_data);
 	};
 
 This has the following fields:
diff --git a/fs/9p/cache.c b/fs/9p/cache.c
index 103ca5e1267b..64c58eb26159 100644
--- a/fs/9p/cache.c
+++ b/fs/9p/cache.c
@@ -151,34 +151,6 @@ fscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data,
 	return FSCACHE_CHECKAUX_OKAY;
 }
 
-static void v9fs_cache_inode_now_uncached(void *cookie_netfs_data)
-{
-	struct v9fs_inode *v9inode = cookie_netfs_data;
-	struct pagevec pvec;
-	pgoff_t first;
-	int loop, nr_pages;
-
-	pagevec_init(&pvec, 0);
-	first = 0;
-
-	for (;;) {
-		nr_pages = pagevec_lookup(&pvec, v9inode->vfs_inode.i_mapping,
-					  first,
-					  PAGEVEC_SIZE - pagevec_count(&pvec));
-		if (!nr_pages)
-			break;
-
-		for (loop = 0; loop < nr_pages; loop++)
-			ClearPageFsCache(pvec.pages[loop]);
-
-		first = pvec.pages[nr_pages - 1]->index + 1;
-
-		pvec.nr = nr_pages;
-		pagevec_release(&pvec);
-		cond_resched();
-	}
-}
-
 const struct fscache_cookie_def v9fs_cache_inode_index_def = {
 	.name		= "9p.inode",
 	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,
@@ -186,7 +158,6 @@ const struct fscache_cookie_def v9fs_cache_inode_index_def = {
 	.get_attr	= v9fs_cache_inode_get_attr,
 	.get_aux	= v9fs_cache_inode_get_aux,
 	.check_aux	= v9fs_cache_inode_check_aux,
-	.now_uncached	= v9fs_cache_inode_now_uncached,
 };
 
 void v9fs_cache_inode_get_cookie(struct inode *inode)
diff --git a/fs/afs/cache.c b/fs/afs/cache.c
index 577763c3d88b..1fe855191261 100644
--- a/fs/afs/cache.c
+++ b/fs/afs/cache.c
@@ -39,7 +39,6 @@ static uint16_t afs_vnode_cache_get_aux(const void *cookie_netfs_data,
 static enum fscache_checkaux afs_vnode_cache_check_aux(void *cookie_netfs_data,
 						       const void *buffer,
 						       uint16_t buflen);
-static void afs_vnode_cache_now_uncached(void *cookie_netfs_data);
 
 struct fscache_netfs afs_cache_netfs = {
 	.name			= "afs",
@@ -75,7 +74,6 @@ struct fscache_cookie_def afs_vnode_cache_index_def = {
 	.get_attr		= afs_vnode_cache_get_attr,
 	.get_aux		= afs_vnode_cache_get_aux,
 	.check_aux		= afs_vnode_cache_check_aux,
-	.now_uncached		= afs_vnode_cache_now_uncached,
 };
 
 /*
@@ -359,44 +357,3 @@ static enum fscache_checkaux afs_vnode_cache_check_aux(void *cookie_netfs_data,
 	_leave(" = SUCCESS");
 	return FSCACHE_CHECKAUX_OKAY;
 }
-
-/*
- * indication the cookie is no longer uncached
- * - this function is called when the backing store currently caching a cookie
- *   is removed
- * - the netfs should use this to clean up any markers indicating cached pages
- * - this is mandatory for any object that may have data
- */
-static void afs_vnode_cache_now_uncached(void *cookie_netfs_data)
-{
-	struct afs_vnode *vnode = cookie_netfs_data;
-	struct pagevec pvec;
-	pgoff_t first;
-	int loop, nr_pages;
-
-	_enter("{%x,%x,%Lx}",
-	       vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version);
-
-	pagevec_init(&pvec, 0);
-	first = 0;
-
-	for (;;) {
-		/* grab a bunch of pages to clean */
-		nr_pages = pagevec_lookup(&pvec, vnode->vfs_inode.i_mapping,
-					  first,
-					  PAGEVEC_SIZE - pagevec_count(&pvec));
-		if (!nr_pages)
-			break;
-
-		for (loop = 0; loop < nr_pages; loop++)
-			ClearPageFsCache(pvec.pages[loop]);
-
-		first = pvec.pages[nr_pages - 1]->index + 1;
-
-		pvec.nr = nr_pages;
-		pagevec_release(&pvec);
-		cond_resched();
-	}
-
-	_leave("");
-}
diff --git a/fs/ceph/cache.c b/fs/ceph/cache.c
index fd1172823f86..6d3baf61b4d5 100644
--- a/fs/ceph/cache.c
+++ b/fs/ceph/cache.c
@@ -194,36 +194,6 @@ static enum fscache_checkaux ceph_fscache_inode_check_aux(
 	return FSCACHE_CHECKAUX_OKAY;
 }
 
-static void ceph_fscache_inode_now_uncached(void* cookie_netfs_data)
-{
-	struct ceph_inode_info* ci = cookie_netfs_data;
-	struct pagevec pvec;
-	pgoff_t first;
-	int loop, nr_pages;
-
-	pagevec_init(&pvec, 0);
-	first = 0;
-
-	dout("ceph inode 0x%p now uncached", ci);
-
-	while (1) {
-		nr_pages = pagevec_lookup(&pvec, ci->vfs_inode.i_mapping, first,
-					  PAGEVEC_SIZE - pagevec_count(&pvec));
-
-		if (!nr_pages)
-			break;
-
-		for (loop = 0; loop < nr_pages; loop++)
-			ClearPageFsCache(pvec.pages[loop]);
-
-		first = pvec.pages[nr_pages - 1]->index + 1;
-
-		pvec.nr = nr_pages;
-		pagevec_release(&pvec);
-		cond_resched();
-	}
-}
-
 static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
 	.name		= "CEPH.inode",
 	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,
@@ -231,7 +201,6 @@ static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
 	.get_attr	= ceph_fscache_inode_get_attr,
 	.get_aux	= ceph_fscache_inode_get_aux,
 	.check_aux	= ceph_fscache_inode_check_aux,
-	.now_uncached	= ceph_fscache_inode_now_uncached,
 };
 
 void ceph_fscache_register_inode_cookie(struct inode *inode)
diff --git a/fs/cifs/cache.c b/fs/cifs/cache.c
index 6c665bf4a27c..2c14020e5e1d 100644
--- a/fs/cifs/cache.c
+++ b/fs/cifs/cache.c
@@ -292,36 +292,6 @@ fscache_checkaux cifs_fscache_inode_check_aux(void *cookie_netfs_data,
 	return FSCACHE_CHECKAUX_OKAY;
 }
 
-static void cifs_fscache_inode_now_uncached(void *cookie_netfs_data)
-{
-	struct cifsInodeInfo *cifsi = cookie_netfs_data;
-	struct pagevec pvec;
-	pgoff_t first;
-	int loop, nr_pages;
-
-	pagevec_init(&pvec, 0);
-	first = 0;
-
-	cifs_dbg(FYI, "%s: cifs inode 0x%p now uncached\n", __func__, cifsi);
-
-	for (;;) {
-		nr_pages = pagevec_lookup(&pvec,
-					  cifsi->vfs_inode.i_mapping, first,
-					  PAGEVEC_SIZE - pagevec_count(&pvec));
-		if (!nr_pages)
-			break;
-
-		for (loop = 0; loop < nr_pages; loop++)
-			ClearPageFsCache(pvec.pages[loop]);
-
-		first = pvec.pages[nr_pages - 1]->index + 1;
-
-		pvec.nr = nr_pages;
-		pagevec_release(&pvec);
-		cond_resched();
-	}
-}
-
 const struct fscache_cookie_def cifs_fscache_inode_object_def = {
 	.name		= "CIFS.uniqueid",
 	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,
@@ -329,5 +299,4 @@ const struct fscache_cookie_def cifs_fscache_inode_object_def = {
 	.get_attr	= cifs_fscache_inode_get_attr,
 	.get_aux	= cifs_fscache_inode_get_aux,
 	.check_aux	= cifs_fscache_inode_check_aux,
-	.now_uncached	= cifs_fscache_inode_now_uncached,
 };
diff --git a/fs/nfs/fscache-index.c b/fs/nfs/fscache-index.c
index 777b055063f6..3025fe8584a0 100644
--- a/fs/nfs/fscache-index.c
+++ b/fs/nfs/fscache-index.c
@@ -252,45 +252,6 @@ enum fscache_checkaux nfs_fscache_inode_check_aux(void *cookie_netfs_data,
 }
 
 /*
- * Indication from FS-Cache that the cookie is no longer cached
- * - This function is called when the backing store currently caching a cookie
- *   is removed
- * - The netfs should use this to clean up any markers indicating cached pages
- * - This is mandatory for any object that may have data
- */
-static void nfs_fscache_inode_now_uncached(void *cookie_netfs_data)
-{
-	struct nfs_inode *nfsi = cookie_netfs_data;
-	struct pagevec pvec;
-	pgoff_t first;
-	int loop, nr_pages;
-
-	pagevec_init(&pvec, 0);
-	first = 0;
-
-	dprintk("NFS: nfs_inode_now_uncached: nfs_inode 0x%p\n", nfsi);
-
-	for (;;) {
-		/* grab a bunch of pages to unmark */
-		nr_pages = pagevec_lookup(&pvec,
-					  nfsi->vfs_inode.i_mapping,
-					  first,
-					  PAGEVEC_SIZE - pagevec_count(&pvec));
-		if (!nr_pages)
-			break;
-
-		for (loop = 0; loop < nr_pages; loop++)
-			ClearPageFsCache(pvec.pages[loop]);
-
-		first = pvec.pages[nr_pages - 1]->index + 1;
-
-		pvec.nr = nr_pages;
-		pagevec_release(&pvec);
-		cond_resched();
-	}
-}
-
-/*
  * Get an extra reference on a read context.
  * - This function can be absent if the completion function doesn't require a
  *   context.
@@ -330,7 +291,6 @@ const struct fscache_cookie_def nfs_fscache_inode_object_def = {
 	.get_attr	= nfs_fscache_inode_get_attr,
 	.get_aux	= nfs_fscache_inode_get_aux,
 	.check_aux	= nfs_fscache_inode_check_aux,
-	.now_uncached	= nfs_fscache_inode_now_uncached,
 	.get_context	= nfs_fh_get_context,
 	.put_context	= nfs_fh_put_context,
 };
diff --git a/include/linux/fscache.h b/include/linux/fscache.h
index 115bb81912cc..f4ff47d4a893 100644
--- a/include/linux/fscache.h
+++ b/include/linux/fscache.h
@@ -143,15 +143,6 @@ struct fscache_cookie_def {
 	void (*mark_page_cached)(void *cookie_netfs_data,
 				 struct address_space *mapping,
 				 struct page *page);
-
-	/* indicate the cookie is no longer cached
-	 * - this function is called when the backing store currently caching
-	 *   a cookie is removed
-	 * - the netfs should use this to clean up any markers indicating
-	 *   cached pages
-	 * - this is mandatory for any object that may have data
-	 */
-	void (*now_uncached)(void *cookie_netfs_data);
 };
 
 /*
-- 
2.12.3

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[PATCH 02/10] mm: Make pagevec_lookup() update index

[Jan Kara]

Make pagevec_lookup() (and underlying find_get_pages()) update index to
the next page where iteration should continue. Most callers want this
and also pagevec_lookup_tag() already does this.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/buffer.c             | 10 ++++------
 fs/ext4/file.c          |  4 +---
 fs/ext4/inode.c         |  8 ++------
 fs/fscache/page.c       |  5 ++---
 fs/hugetlbfs/inode.c    | 17 ++++++++---------
 fs/nilfs2/page.c        |  3 +--
 fs/ramfs/file-nommu.c   |  2 +-
 include/linux/pagemap.h |  2 +-
 include/linux/pagevec.h |  2 +-
 mm/filemap.c            | 11 ++++++++---
 mm/swap.c               |  5 +++--
 11 files changed, 32 insertions(+), 37 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 5715dac7821f..5b20893708e2 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1633,13 +1633,12 @@ void clean_bdev_aliases(struct block_device *bdev, sector_t block, sector_t len)
 
 	end = (block + len - 1) >> (PAGE_SHIFT - bd_inode->i_blkbits);
 	pagevec_init(&pvec, 0);
-	while (index <= end && pagevec_lookup(&pvec, bd_mapping, index,
+	while (index <= end && pagevec_lookup(&pvec, bd_mapping, &index,
 			min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) {
 		for (i = 0; i < pagevec_count(&pvec); i++) {
 			struct page *page = pvec.pages[i];
 
-			index = page->index;
-			if (index > end)
+			if (page->index > end)
 				break;
 			if (!page_has_buffers(page))
 				continue;
@@ -1670,7 +1669,6 @@ void clean_bdev_aliases(struct block_device *bdev, sector_t block, sector_t len)
 		}
 		pagevec_release(&pvec);
 		cond_resched();
-		index++;
 	}
 }
 EXPORT_SYMBOL(clean_bdev_aliases);
@@ -3552,7 +3550,8 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length,
 		unsigned want, nr_pages, i;
 
 		want = min_t(unsigned, end - index, PAGEVEC_SIZE);
-		nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index, want);
+		nr_pages = pagevec_lookup(&pvec, inode->i_mapping, &index,
+					  want);
 		if (nr_pages == 0)
 			break;
 
@@ -3594,7 +3593,6 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length,
 		if (nr_pages < want)
 			break;
 
-		index = pvec.pages[i - 1]->index + 1;
 		pagevec_release(&pvec);
 	} while (index < end);
 
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 58294c9a7e1d..ab09cb6fcce3 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -498,7 +498,7 @@ static int ext4_find_unwritten_pgoff(struct inode *inode,
 		unsigned long nr_pages;
 
 		num = min_t(pgoff_t, end - index, PAGEVEC_SIZE - 1) + 1;
-		nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index,
+		nr_pages = pagevec_lookup(&pvec, inode->i_mapping, &index,
 					  (pgoff_t)num);
 		if (nr_pages == 0)
 			break;
@@ -563,8 +563,6 @@ static int ext4_find_unwritten_pgoff(struct inode *inode,
 		/* The no. of pages is less than our desired, we are done. */
 		if (nr_pages < num)
 			break;
-
-		index = pvec.pages[i - 1]->index + 1;
 		pagevec_release(&pvec);
 	} while (index <= end);
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 3c600f02673f..68d0166d5ebc 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1676,7 +1676,7 @@ static void mpage_release_unused_pages(struct mpage_da_data *mpd,
 
 	pagevec_init(&pvec, 0);
 	while (index <= end) {
-		nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
+		nr_pages = pagevec_lookup(&pvec, mapping, &index, PAGEVEC_SIZE);
 		if (nr_pages == 0)
 			break;
 		for (i = 0; i < nr_pages; i++) {
@@ -1693,7 +1693,6 @@ static void mpage_release_unused_pages(struct mpage_da_data *mpd,
 			}
 			unlock_page(page);
 		}
-		index = pvec.pages[nr_pages - 1]->index + 1;
 		pagevec_release(&pvec);
 	}
 }
@@ -2304,7 +2303,7 @@ static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
 
 	pagevec_init(&pvec, 0);
 	while (start <= end) {
-		nr_pages = pagevec_lookup(&pvec, inode->i_mapping, start,
+		nr_pages = pagevec_lookup(&pvec, inode->i_mapping, &start,
 					  PAGEVEC_SIZE);
 		if (nr_pages == 0)
 			break;
@@ -2313,8 +2312,6 @@ static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
 
 			if (page->index > end)
 				break;
-			/* Up to 'end' pages must be contiguous */
-			BUG_ON(page->index != start);
 			bh = head = page_buffers(page);
 			do {
 				if (lblk < mpd->map.m_lblk)
@@ -2359,7 +2356,6 @@ static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
 				pagevec_release(&pvec);
 				return err;
 			}
-			start++;
 		}
 		pagevec_release(&pvec);
 	}
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index c8c4f79c7ce1..83018861dcd2 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -1178,11 +1178,10 @@ void __fscache_uncache_all_inode_pages(struct fscache_cookie *cookie,
 	pagevec_init(&pvec, 0);
 	next = 0;
 	do {
-		if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE))
+		if (!pagevec_lookup(&pvec, mapping, &next, PAGEVEC_SIZE))
 			break;
 		for (i = 0; i < pagevec_count(&pvec); i++) {
 			struct page *page = pvec.pages[i];
-			next = page->index;
 			if (PageFsCache(page)) {
 				__fscache_wait_on_page_write(cookie, page);
 				__fscache_uncache_page(cookie, page);
@@ -1190,7 +1189,7 @@ void __fscache_uncache_all_inode_pages(struct fscache_cookie *cookie,
 		}
 		pagevec_release(&pvec);
 		cond_resched();
-	} while (++next);
+	} while (next);
 
 	_leave("");
 }
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 28d2753be094..b9678ce91e25 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -401,7 +401,7 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 	const pgoff_t end = lend >> huge_page_shift(h);
 	struct vm_area_struct pseudo_vma;
 	struct pagevec pvec;
-	pgoff_t next;
+	pgoff_t next, index;
 	int i, freed = 0;
 	long lookup_nr = PAGEVEC_SIZE;
 	bool truncate_op = (lend == LLONG_MAX);
@@ -420,7 +420,7 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 		/*
 		 * When no more pages are found, we are done.
 		 */
-		if (!pagevec_lookup(&pvec, mapping, next, lookup_nr))
+		if (!pagevec_lookup(&pvec, mapping, &next, lookup_nr))
 			break;
 
 		for (i = 0; i < pagevec_count(&pvec); ++i) {
@@ -432,13 +432,13 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 			 * only possible in the punch hole case as end is
 			 * max page offset in the truncate case.
 			 */
-			next = page->index;
-			if (next >= end)
+			index = page->index;
+			if (index >= end)
 				break;
 
 			hash = hugetlb_fault_mutex_hash(h, current->mm,
 							&pseudo_vma,
-							mapping, next, 0);
+							mapping, index, 0);
 			mutex_lock(&hugetlb_fault_mutex_table[hash]);
 
 			/*
@@ -455,8 +455,8 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 
 				i_mmap_lock_write(mapping);
 				hugetlb_vmdelete_list(&mapping->i_mmap,
-					next * pages_per_huge_page(h),
-					(next + 1) * pages_per_huge_page(h));
+					index * pages_per_huge_page(h),
+					(index + 1) * pages_per_huge_page(h));
 				i_mmap_unlock_write(mapping);
 			}
 
@@ -475,14 +475,13 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 			freed++;
 			if (!truncate_op) {
 				if (unlikely(hugetlb_unreserve_pages(inode,
-							next, next + 1, 1)))
+							index, index + 1, 1)))
 					hugetlb_fix_reserve_counts(inode);
 			}
 
 			unlock_page(page);
 			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 		}
-		++next;
 		huge_pagevec_release(&pvec);
 		cond_resched();
 	}
diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c
index f11a3ad2df0c..382a36c72d72 100644
--- a/fs/nilfs2/page.c
+++ b/fs/nilfs2/page.c
@@ -312,10 +312,9 @@ void nilfs_copy_back_pages(struct address_space *dmap,
 
 	pagevec_init(&pvec, 0);
 repeat:
-	n = pagevec_lookup(&pvec, smap, index, PAGEVEC_SIZE);
+	n = pagevec_lookup(&pvec, smap, &index, PAGEVEC_SIZE);
 	if (!n)
 		return;
-	index = pvec.pages[n - 1]->index + 1;
 
 	for (i = 0; i < pagevec_count(&pvec); i++) {
 		struct page *page = pvec.pages[i], *dpage;
diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c
index 2ef7ce75c062..3ac1f2387083 100644
--- a/fs/ramfs/file-nommu.c
+++ b/fs/ramfs/file-nommu.c
@@ -228,7 +228,7 @@ static unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
 	if (!pages)
 		goto out_free;
 
-	nr = find_get_pages(inode->i_mapping, pgoff, lpages, pages);
+	nr = find_get_pages(inode->i_mapping, &pgoff, lpages, pages);
 	if (nr != lpages)
 		goto out_free_pages; /* leave if some pages were missing */
 
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index baa9344dcd10..1ea73bd6952b 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -355,7 +355,7 @@ struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset);
 unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
 			  unsigned int nr_entries, struct page **entries,
 			  pgoff_t *indices);
-unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
+unsigned find_get_pages(struct address_space *mapping, pgoff_t *start,
 			unsigned int nr_pages, struct page **pages);
 unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
 			       unsigned int nr_pages, struct page **pages);
diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h
index b45d391b4540..c395a5bb58b2 100644
--- a/include/linux/pagevec.h
+++ b/include/linux/pagevec.h
@@ -28,7 +28,7 @@ unsigned pagevec_lookup_entries(struct pagevec *pvec,
 				pgoff_t *indices);
 void pagevec_remove_exceptionals(struct pagevec *pvec);
 unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,
-		pgoff_t start, unsigned nr_pages);
+		pgoff_t *start, unsigned nr_pages);
 unsigned pagevec_lookup_tag(struct pagevec *pvec,
 		struct address_space *mapping, pgoff_t *index, int tag,
 		unsigned nr_pages);
diff --git a/mm/filemap.c b/mm/filemap.c
index a49702445ce0..c3a9c6375eb9 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -412,7 +412,7 @@ bool filemap_range_has_page(struct address_space *mapping,
 		return false;
 
 	pagevec_init(&pvec, 0);
-	if (!pagevec_lookup(&pvec, mapping, index, 1))
+	if (!pagevec_lookup(&pvec, mapping, &index, 1))
 		return false;
 	ret = (pvec.pages[0]->index <= end);
 	pagevec_release(&pvec);
@@ -1576,10 +1576,11 @@ unsigned find_get_entries(struct address_space *mapping,
  *
  * The search returns a group of mapping-contiguous pages with ascending
  * indexes.  There may be holes in the indices due to not-present pages.
+ * We also update @start to index the next page for the traversal.
  *
  * find_get_pages() returns the number of pages which were found.
  */
-unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
+unsigned find_get_pages(struct address_space *mapping, pgoff_t *start,
 			    unsigned int nr_pages, struct page **pages)
 {
 	struct radix_tree_iter iter;
@@ -1590,7 +1591,7 @@ unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
 		return 0;
 
 	rcu_read_lock();
-	radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
+	radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, *start) {
 		struct page *head, *page;
 repeat:
 		page = radix_tree_deref_slot(slot);
@@ -1632,6 +1633,10 @@ unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
 	}
 
 	rcu_read_unlock();
+
+	if (ret)
+		*start = pages[ret - 1]->index + 1;
+
 	return ret;
 }
 
diff --git a/mm/swap.c b/mm/swap.c
index 60b1d2a75852..4bffd1198ce5 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -957,12 +957,13 @@ void pagevec_remove_exceptionals(struct pagevec *pvec)
  * reference against the pages in @pvec.
  *
  * The search returns a group of mapping-contiguous pages with ascending
- * indexes.  There may be holes in the indices due to not-present pages.
+ * indexes.  There may be holes in the indices due to not-present pages. We
+ * also update @start to index the next page for the traversal.
  *
  * pagevec_lookup() returns the number of pages which were found.
  */
 unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,
-		pgoff_t start, unsigned nr_pages)
+		pgoff_t *start, unsigned nr_pages)
 {
 	pvec->nr = find_get_pages(mapping, start, nr_pages, pvec->pages);
 	return pagevec_count(pvec);
-- 
2.12.3

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[PATCH 03/10] mm: Implement find_get_pages_range()

[Jan Kara]

Implement a variant of find_get_pages() that stops iterating at given
index. This may be substantial performance gain if the mapping is
sparse. See following commit for details. Furthermore lots of users of
this function (through pagevec_lookup()) actually want a range lookup
and all of them are currently open-coding this.

Also create corresponding pagevec_lookup_range() function.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 include/linux/pagemap.h | 12 ++++++++++--
 include/linux/pagevec.h | 13 +++++++++++--
 mm/filemap.c            | 42 ++++++++++++++++++++++++++++++------------
 mm/swap.c               | 22 ++++++++++++++--------
 4 files changed, 65 insertions(+), 24 deletions(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 1ea73bd6952b..bbccf6f22fd7 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -355,8 +355,16 @@ struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset);
 unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
 			  unsigned int nr_entries, struct page **entries,
 			  pgoff_t *indices);
-unsigned find_get_pages(struct address_space *mapping, pgoff_t *start,
-			unsigned int nr_pages, struct page **pages);
+unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start,
+			pgoff_t end, unsigned int nr_pages,
+			struct page **pages);
+static inline unsigned find_get_pages(struct address_space *mapping,
+			pgoff_t *start, unsigned int nr_pages,
+			struct page **pages)
+{
+	return find_get_pages_range(mapping, start, (pgoff_t)-1, nr_pages,
+				    pages);
+}
 unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
 			       unsigned int nr_pages, struct page **pages);
 unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h
index c395a5bb58b2..7df056910437 100644
--- a/include/linux/pagevec.h
+++ b/include/linux/pagevec.h
@@ -27,8 +27,17 @@ unsigned pagevec_lookup_entries(struct pagevec *pvec,
 				pgoff_t start, unsigned nr_entries,
 				pgoff_t *indices);
 void pagevec_remove_exceptionals(struct pagevec *pvec);
-unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,
-		pgoff_t *start, unsigned nr_pages);
+unsigned pagevec_lookup_range(struct pagevec *pvec,
+			      struct address_space *mapping,
+			      pgoff_t *start, pgoff_t end, unsigned nr_pages);
+static inline unsigned pagevec_lookup(struct pagevec *pvec,
+				      struct address_space *mapping,
+				      pgoff_t *start, unsigned nr_pages)
+{
+	return pagevec_lookup_range(pvec, mapping, start, (pgoff_t)-1,
+				    nr_pages);
+}
+
 unsigned pagevec_lookup_tag(struct pagevec *pvec,
 		struct address_space *mapping, pgoff_t *index, int tag,
 		unsigned nr_pages);
diff --git a/mm/filemap.c b/mm/filemap.c
index c3a9c6375eb9..b02be926a115 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1564,24 +1564,29 @@ unsigned find_get_entries(struct address_space *mapping,
 }
 
 /**
- * find_get_pages - gang pagecache lookup
+ * find_get_pages_range - gang pagecache lookup
  * @mapping:	The address_space to search
  * @start:	The starting page index
+ * @end:	The final page index (inclusive)
  * @nr_pages:	The maximum number of pages
  * @pages:	Where the resulting pages are placed
  *
- * find_get_pages() will search for and return a group of up to
- * @nr_pages pages in the mapping.  The pages are placed at @pages.
- * find_get_pages() takes a reference against the returned pages.
+ * find_get_pages_range() will search for and return a group of up to @nr_pages
+ * pages in the mapping starting at index @start and up to index @end
+ * (inclusive).  The pages are placed at @pages.  find_get_pages_range() takes
+ * a reference against the returned pages.
  *
  * The search returns a group of mapping-contiguous pages with ascending
  * indexes.  There may be holes in the indices due to not-present pages.
  * We also update @start to index the next page for the traversal.
  *
- * find_get_pages() returns the number of pages which were found.
+ * find_get_pages_range() returns the number of pages which were found. If this
+ * number is smaller than @nr_pages, the end of specified range has been
+ * reached.
  */
-unsigned find_get_pages(struct address_space *mapping, pgoff_t *start,
-			    unsigned int nr_pages, struct page **pages)
+unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start,
+			      pgoff_t end, unsigned int nr_pages,
+			      struct page **pages)
 {
 	struct radix_tree_iter iter;
 	void **slot;
@@ -1593,6 +1598,9 @@ unsigned find_get_pages(struct address_space *mapping, pgoff_t *start,
 	rcu_read_lock();
 	radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, *start) {
 		struct page *head, *page;
+
+		if (iter.index > end)
+			break;
 repeat:
 		page = radix_tree_deref_slot(slot);
 		if (unlikely(!page))
@@ -1628,15 +1636,25 @@ unsigned find_get_pages(struct address_space *mapping, pgoff_t *start,
 		}
 
 		pages[ret] = page;
-		if (++ret == nr_pages)
-			break;
+		if (++ret == nr_pages) {
+			*start = pages[ret - 1]->index + 1;
+			goto out;
+		}
 	}
 
+	/*
+	 * We come here when there is no page beyond @end. We take care to not
+	 * overflow the index @start as it confuses some of the callers. This
+	 * breaks the iteration when there is page at index -1 but that is
+	 * already broken anyway.
+	 */
+	if (end == (pgoff_t)-1)
+		*start = (pgoff_t)-1;
+	else
+		*start = end + 1;
+out:
 	rcu_read_unlock();
 
-	if (ret)
-		*start = pages[ret - 1]->index + 1;
-
 	return ret;
 }
 
diff --git a/mm/swap.c b/mm/swap.c
index 4bffd1198ce5..e06e9aa2478e 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -946,29 +946,35 @@ void pagevec_remove_exceptionals(struct pagevec *pvec)
 }
 
 /**
- * pagevec_lookup - gang pagecache lookup
+ * pagevec_lookup_range - gang pagecache lookup
  * @pvec:	Where the resulting pages are placed
  * @mapping:	The address_space to search
  * @start:	The starting page index
+ * @end:	The final page index
  * @nr_pages:	The maximum number of pages
  *
- * pagevec_lookup() will search for and return a group of up to @nr_pages pages
- * in the mapping.  The pages are placed in @pvec.  pagevec_lookup() takes a
+ * pagevec_lookup_range() will search for and return a group of up to @nr_pages
+ * pages in the mapping starting from index @start and upto index @end
+ * (inclusive).  The pages are placed in @pvec.  pagevec_lookup() takes a
  * reference against the pages in @pvec.
  *
  * The search returns a group of mapping-contiguous pages with ascending
  * indexes.  There may be holes in the indices due to not-present pages. We
  * also update @start to index the next page for the traversal.
  *
- * pagevec_lookup() returns the number of pages which were found.
+ * pagevec_lookup_range() returns the number of pages which were found. If this
+ * number is smaller than @nr_pages, the end of specified range has been
+ * reached.
  */
-unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,
-		pgoff_t *start, unsigned nr_pages)
+unsigned pagevec_lookup_range(struct pagevec *pvec,
+		struct address_space *mapping, pgoff_t *start, pgoff_t end,
+		unsigned nr_pages)
 {
-	pvec->nr = find_get_pages(mapping, start, nr_pages, pvec->pages);
+	pvec->nr = find_get_pages_range(mapping, start, end, nr_pages,
+					pvec->pages);
 	return pagevec_count(pvec);
 }
-EXPORT_SYMBOL(pagevec_lookup);
+EXPORT_SYMBOL(pagevec_lookup_range);
 
 unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping,
 		pgoff_t *index, int tag, unsigned nr_pages)
-- 
2.12.3

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[PATCH 04/10] fs: Fix performance regression in clean_bdev_aliases()

[Jan Kara]

Commit e64855c6cfaa "fs: Add helper to clean bdev aliases under a bh and
use it" added a wrapper for clean_bdev_aliases() that invalidates bdev
aliases underlying a single buffer head. However this has caused a
performance regression for bonnie++ benchmark on ext4 filesystem when
delayed allocation is turned off (ext3 mode) - average of 3 runs:

Hmean SeqOut Char  164787.55 (  0.00%) 107189.06 (-34.95%)
Hmean SeqOut Block 219883.89 (  0.00%) 168870.32 (-23.20%)

The reason for this regression is that clean_bdev_aliases() is slower
when called for a single block because pagevec_lookup() it uses will end
up iterating through the radix tree until it finds a page (which may
take a while) but we are only interested whether there's a page at a
particular index.

Fix the problem by using pagevec_lookup_range() instead which avoids the
needless iteration.

Fixes: e64855c6cfaa0a80c1b71c5f647cb792dc436668
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/buffer.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 5b20893708e2..7e531bb356bd 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1627,19 +1627,18 @@ void clean_bdev_aliases(struct block_device *bdev, sector_t block, sector_t len)
 	struct pagevec pvec;
 	pgoff_t index = block >> (PAGE_SHIFT - bd_inode->i_blkbits);
 	pgoff_t end;
-	int i;
+	int i, count;
 	struct buffer_head *bh;
 	struct buffer_head *head;
 
 	end = (block + len - 1) >> (PAGE_SHIFT - bd_inode->i_blkbits);
 	pagevec_init(&pvec, 0);
-	while (index <= end && pagevec_lookup(&pvec, bd_mapping, &index,
-			min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) {
-		for (i = 0; i < pagevec_count(&pvec); i++) {
+	while (pagevec_lookup_range(&pvec, bd_mapping, &index, end,
+				    PAGEVEC_SIZE)) {
+		count = pagevec_count(&pvec);
+		for (i = 0; i < count; i++) {
 			struct page *page = pvec.pages[i];
 
-			if (page->index > end)
-				break;
 			if (!page_has_buffers(page))
 				continue;
 			/*
@@ -1669,6 +1668,9 @@ void clean_bdev_aliases(struct block_device *bdev, sector_t block, sector_t len)
 		}
 		pagevec_release(&pvec);
 		cond_resched();
+		/* End of range already reached? */
+		if (index > end || !index)
+			break;
 	}
 }
 EXPORT_SYMBOL(clean_bdev_aliases);
-- 
2.12.3

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[PATCH 05/10] ext4: Use pagevec_lookup_range() in ext4_find_unwritten_pgoff()

[Jan Kara]

Use pagevec_lookup_range() in ext4_find_unwritten_pgoff() since we are
interested only in pages in the given range. Simplify the logic as a
result of not getting pages out of range and index getting automatically
advanced.

CC: linux-ext4@vger.kernel.org
CC: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/file.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index ab09cb6fcce3..ac39a6a1ea5d 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -494,12 +494,11 @@ static int ext4_find_unwritten_pgoff(struct inode *inode,
 
 	pagevec_init(&pvec, 0);
 	do {
-		int i, num;
+		int i;
 		unsigned long nr_pages;
 
-		num = min_t(pgoff_t, end - index, PAGEVEC_SIZE - 1) + 1;
-		nr_pages = pagevec_lookup(&pvec, inode->i_mapping, &index,
-					  (pgoff_t)num);
+		nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping,
+					&index, end, PAGEVEC_SIZE);
 		if (nr_pages == 0)
 			break;
 
@@ -518,9 +517,6 @@ static int ext4_find_unwritten_pgoff(struct inode *inode,
 				goto out;
 			}
 
-			if (page->index > end)
-				goto out;
-
 			lock_page(page);
 
 			if (unlikely(page->mapping != inode->i_mapping)) {
@@ -560,12 +556,10 @@ static int ext4_find_unwritten_pgoff(struct inode *inode,
 			unlock_page(page);
 		}
 
-		/* The no. of pages is less than our desired, we are done. */
-		if (nr_pages < num)
-			break;
 		pagevec_release(&pvec);
 	} while (index <= end);
 
+	/* There are no pages upto endoff - that would be a hole in there. */
 	if (whence == SEEK_HOLE && lastoff < endoff) {
 		found = 1;
 		*offset = lastoff;
-- 
2.12.3

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[PATCH 06/10] ext4: Use pagevec_lookup_range() in writeback code

[Jan Kara]

Both occurences of pagevec_lookup() actually want only pages from a
given range. Use pagevec_lookup_range() for the lookup.

CC: "Theodore Ts'o" <tytso@mit.edu>
CC: linux-ext4@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/inode.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 68d0166d5ebc..eb86c1baf40c 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1676,13 +1676,13 @@ static void mpage_release_unused_pages(struct mpage_da_data *mpd,
 
 	pagevec_init(&pvec, 0);
 	while (index <= end) {
-		nr_pages = pagevec_lookup(&pvec, mapping, &index, PAGEVEC_SIZE);
+		nr_pages = pagevec_lookup_range(&pvec, mapping, &index, end,
+						PAGEVEC_SIZE);
 		if (nr_pages == 0)
 			break;
 		for (i = 0; i < nr_pages; i++) {
 			struct page *page = pvec.pages[i];
-			if (page->index > end)
-				break;
+
 			BUG_ON(!PageLocked(page));
 			BUG_ON(PageWriteback(page));
 			if (invalidate) {
@@ -2303,15 +2303,13 @@ static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
 
 	pagevec_init(&pvec, 0);
 	while (start <= end) {
-		nr_pages = pagevec_lookup(&pvec, inode->i_mapping, &start,
-					  PAGEVEC_SIZE);
+		nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping,
+						&start, end, PAGEVEC_SIZE);
 		if (nr_pages == 0)
 			break;
 		for (i = 0; i < nr_pages; i++) {
 			struct page *page = pvec.pages[i];
 
-			if (page->index > end)
-				break;
 			bh = head = page_buffers(page);
 			do {
 				if (lblk < mpd->map.m_lblk)
-- 
2.12.3

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[PATCH 07/10] hugetlbfs: Use pagevec_lookup_range() in remove_inode_hugepages()

[Jan Kara]

We want only pages from given range in remove_inode_hugepages(). Use
pagevec_lookup_range() instead of pagevec_lookup().

CC: Nadia Yvette Chambers <nyc@holomorphy.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/hugetlbfs/inode.c | 18 ++----------------
 1 file changed, 2 insertions(+), 16 deletions(-)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index b9678ce91e25..8931236f3ef4 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -403,7 +403,6 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 	struct pagevec pvec;
 	pgoff_t next, index;
 	int i, freed = 0;
-	long lookup_nr = PAGEVEC_SIZE;
 	bool truncate_op = (lend == LLONG_MAX);
 
 	memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
@@ -412,30 +411,17 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 	next = start;
 	while (next < end) {
 		/*
-		 * Don't grab more pages than the number left in the range.
-		 */
-		if (end - next < lookup_nr)
-			lookup_nr = end - next;
-
-		/*
 		 * When no more pages are found, we are done.
 		 */
-		if (!pagevec_lookup(&pvec, mapping, &next, lookup_nr))
+		if (!pagevec_lookup_range(&pvec, mapping, &next, end - 1,
+					  PAGEVEC_SIZE))
 			break;
 
 		for (i = 0; i < pagevec_count(&pvec); ++i) {
 			struct page *page = pvec.pages[i];
 			u32 hash;
 
-			/*
-			 * The page (index) could be beyond end.  This is
-			 * only possible in the punch hole case as end is
-			 * max page offset in the truncate case.
-			 */
 			index = page->index;
-			if (index >= end)
-				break;
-
 			hash = hugetlb_fault_mutex_hash(h, current->mm,
 							&pseudo_vma,
 							mapping, index, 0);
-- 
2.12.3

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[PATCH 08/10] fs: Use pagevec_lookup_range() in page_cache_seek_hole_data()

[Jan Kara]

We want only pages from given range in page_cache_seek_hole_data(). Use
pagevec_lookup_range() instead of pagevec_lookup() and remove
unnecessary code. Note that the check for getting less pages than
desired can be removed because index gets updated by
pagevec_lookup_range().

CC: linux-fsdevel@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/buffer.c | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 7e531bb356bd..8770b58ca569 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3549,11 +3549,10 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length,
 	pagevec_init(&pvec, 0);
 
 	do {
-		unsigned want, nr_pages, i;
+		unsigned nr_pages, i;
 
-		want = min_t(unsigned, end - index, PAGEVEC_SIZE);
-		nr_pages = pagevec_lookup(&pvec, inode->i_mapping, &index,
-					  want);
+		nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping, &index,
+						end - 1, PAGEVEC_SIZE);
 		if (nr_pages == 0)
 			break;
 
@@ -3574,10 +3573,6 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length,
 			    lastoff < page_offset(page))
 				goto check_range;
 
-			/* Searching done if the page index is out of range. */
-			if (page->index >= end)
-				goto not_found;
-
 			lock_page(page);
 			if (likely(page->mapping == inode->i_mapping) &&
 			    page_has_buffers(page)) {
@@ -3590,11 +3585,6 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length,
 			unlock_page(page);
 			lastoff = page_offset(page) + PAGE_SIZE;
 		}
-
-		/* Searching done if fewer pages returned than wanted. */
-		if (nr_pages < want)
-			break;
-
 		pagevec_release(&pvec);
 	} while (index < end);
 
-- 
2.12.3

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[PATCH 09/10] mm: Use find_get_pages_range() in filemap_range_has_page()

[Jan Kara]

We want only pages from given range in filemap_range_has_page(),
furthermore we want at most a single page. So use find_get_pages_range()
instead of pagevec_lookup() and remove unnecessary code.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 mm/filemap.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index b02be926a115..871c974f0bb3 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -402,8 +402,7 @@ bool filemap_range_has_page(struct address_space *mapping,
 {
 	pgoff_t index = start_byte >> PAGE_SHIFT;
 	pgoff_t end = end_byte >> PAGE_SHIFT;
-	struct pagevec pvec;
-	bool ret;
+	struct page *page;
 
 	if (end_byte < start_byte)
 		return false;
@@ -411,12 +410,10 @@ bool filemap_range_has_page(struct address_space *mapping,
 	if (mapping->nrpages == 0)
 		return false;
 
-	pagevec_init(&pvec, 0);
-	if (!pagevec_lookup(&pvec, mapping, &index, 1))
+	if (!find_get_pages_range(mapping, &index, end, 1, &page))
 		return false;
-	ret = (pvec.pages[0]->index <= end);
-	pagevec_release(&pvec);
-	return ret;
+	put_page(page);
+	return true;
 }
 EXPORT_SYMBOL(filemap_range_has_page);
 
-- 
2.12.3

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[PATCH 10/10] mm: Remove nr_pages argument from pagevec_lookup{,_range}()

[Jan Kara]

All users of pagevec_lookup() and pagevec_lookup_range() now pass
PAGEVEC_SIZE as a desired number of pages. Just drop the argument.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/buffer.c             | 5 ++---
 fs/ext4/file.c          | 2 +-
 fs/ext4/inode.c         | 5 ++---
 fs/fscache/page.c       | 2 +-
 fs/hugetlbfs/inode.c    | 3 +--
 fs/nilfs2/page.c        | 2 +-
 include/linux/pagevec.h | 7 +++----
 mm/swap.c               | 5 ++---
 8 files changed, 13 insertions(+), 18 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 8770b58ca569..50da0e102ca0 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1633,8 +1633,7 @@ void clean_bdev_aliases(struct block_device *bdev, sector_t block, sector_t len)
 
 	end = (block + len - 1) >> (PAGE_SHIFT - bd_inode->i_blkbits);
 	pagevec_init(&pvec, 0);
-	while (pagevec_lookup_range(&pvec, bd_mapping, &index, end,
-				    PAGEVEC_SIZE)) {
+	while (pagevec_lookup_range(&pvec, bd_mapping, &index, end)) {
 		count = pagevec_count(&pvec);
 		for (i = 0; i < count; i++) {
 			struct page *page = pvec.pages[i];
@@ -3552,7 +3551,7 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length,
 		unsigned nr_pages, i;
 
 		nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping, &index,
-						end - 1, PAGEVEC_SIZE);
+						end - 1);
 		if (nr_pages == 0)
 			break;
 
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index ac39a6a1ea5d..2d5153b343b8 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -498,7 +498,7 @@ static int ext4_find_unwritten_pgoff(struct inode *inode,
 		unsigned long nr_pages;
 
 		nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping,
-					&index, end, PAGEVEC_SIZE);
+					&index, end);
 		if (nr_pages == 0)
 			break;
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index eb86c1baf40c..6bc99d5056cb 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1676,8 +1676,7 @@ static void mpage_release_unused_pages(struct mpage_da_data *mpd,
 
 	pagevec_init(&pvec, 0);
 	while (index <= end) {
-		nr_pages = pagevec_lookup_range(&pvec, mapping, &index, end,
-						PAGEVEC_SIZE);
+		nr_pages = pagevec_lookup_range(&pvec, mapping, &index, end);
 		if (nr_pages == 0)
 			break;
 		for (i = 0; i < nr_pages; i++) {
@@ -2304,7 +2303,7 @@ static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
 	pagevec_init(&pvec, 0);
 	while (start <= end) {
 		nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping,
-						&start, end, PAGEVEC_SIZE);
+						&start, end);
 		if (nr_pages == 0)
 			break;
 		for (i = 0; i < nr_pages; i++) {
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index 83018861dcd2..0ad3fd3ad0b4 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -1178,7 +1178,7 @@ void __fscache_uncache_all_inode_pages(struct fscache_cookie *cookie,
 	pagevec_init(&pvec, 0);
 	next = 0;
 	do {
-		if (!pagevec_lookup(&pvec, mapping, &next, PAGEVEC_SIZE))
+		if (!pagevec_lookup(&pvec, mapping, &next))
 			break;
 		for (i = 0; i < pagevec_count(&pvec); i++) {
 			struct page *page = pvec.pages[i];
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 8931236f3ef4..7c02b3f738e1 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -413,8 +413,7 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 		/*
 		 * When no more pages are found, we are done.
 		 */
-		if (!pagevec_lookup_range(&pvec, mapping, &next, end - 1,
-					  PAGEVEC_SIZE))
+		if (!pagevec_lookup_range(&pvec, mapping, &next, end - 1))
 			break;
 
 		for (i = 0; i < pagevec_count(&pvec); ++i) {
diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c
index 382a36c72d72..8616c46d33da 100644
--- a/fs/nilfs2/page.c
+++ b/fs/nilfs2/page.c
@@ -312,7 +312,7 @@ void nilfs_copy_back_pages(struct address_space *dmap,
 
 	pagevec_init(&pvec, 0);
 repeat:
-	n = pagevec_lookup(&pvec, smap, &index, PAGEVEC_SIZE);
+	n = pagevec_lookup(&pvec, smap, &index);
 	if (!n)
 		return;
 
diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h
index 7df056910437..4dcd5506f1ed 100644
--- a/include/linux/pagevec.h
+++ b/include/linux/pagevec.h
@@ -29,13 +29,12 @@ unsigned pagevec_lookup_entries(struct pagevec *pvec,
 void pagevec_remove_exceptionals(struct pagevec *pvec);
 unsigned pagevec_lookup_range(struct pagevec *pvec,
 			      struct address_space *mapping,
-			      pgoff_t *start, pgoff_t end, unsigned nr_pages);
+			      pgoff_t *start, pgoff_t end);
 static inline unsigned pagevec_lookup(struct pagevec *pvec,
 				      struct address_space *mapping,
-				      pgoff_t *start, unsigned nr_pages)
+				      pgoff_t *start)
 {
-	return pagevec_lookup_range(pvec, mapping, start, (pgoff_t)-1,
-				    nr_pages);
+	return pagevec_lookup_range(pvec, mapping, start, (pgoff_t)-1);
 }
 
 unsigned pagevec_lookup_tag(struct pagevec *pvec,
diff --git a/mm/swap.c b/mm/swap.c
index e06e9aa2478e..62d96b8e5eb3 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -967,10 +967,9 @@ void pagevec_remove_exceptionals(struct pagevec *pvec)
  * reached.
  */
 unsigned pagevec_lookup_range(struct pagevec *pvec,
-		struct address_space *mapping, pgoff_t *start, pgoff_t end,
-		unsigned nr_pages)
+		struct address_space *mapping, pgoff_t *start, pgoff_t end)
 {
-	pvec->nr = find_get_pages_range(mapping, start, end, nr_pages,
+	pvec->nr = find_get_pages_range(mapping, start, end, PAGEVEC_SIZE,
 					pvec->pages);
 	return pagevec_count(pvec);
 }
-- 
2.12.3

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Re: [PATCH 07/10] hugetlbfs: Use pagevec_lookup_range() in remove_inode_hugepages()

[Mike Kravetz]

On 07/26/2017 04:47 AM, Jan Kara wrote:
> We want only pages from given range in remove_inode_hugepages(). Use
> pagevec_lookup_range() instead of pagevec_lookup().
> 
> CC: Nadia Yvette Chambers <nyc@holomorphy.com>
> Signed-off-by: Jan Kara <jack@suse.cz>

Nice.  I like the new interface.

Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>

> ---
>  fs/hugetlbfs/inode.c | 18 ++----------------
>  1 file changed, 2 insertions(+), 16 deletions(-)
> 
> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
> index b9678ce91e25..8931236f3ef4 100644
> --- a/fs/hugetlbfs/inode.c
> +++ b/fs/hugetlbfs/inode.c
> @@ -403,7 +403,6 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
>  	struct pagevec pvec;
>  	pgoff_t next, index;
>  	int i, freed = 0;
> -	long lookup_nr = PAGEVEC_SIZE;
>  	bool truncate_op = (lend == LLONG_MAX);
>  
>  	memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
> @@ -412,30 +411,17 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
>  	next = start;
>  	while (next < end) {
>  		/*
> -		 * Don't grab more pages than the number left in the range.
> -		 */
> -		if (end - next < lookup_nr)
> -			lookup_nr = end - next;
> -
> -		/*
>  		 * When no more pages are found, we are done.
>  		 */
> -		if (!pagevec_lookup(&pvec, mapping, &next, lookup_nr))
> +		if (!pagevec_lookup_range(&pvec, mapping, &next, end - 1,
> +					  PAGEVEC_SIZE))
>  			break;
>  
>  		for (i = 0; i < pagevec_count(&pvec); ++i) {
>  			struct page *page = pvec.pages[i];
>  			u32 hash;
>  
> -			/*
> -			 * The page (index) could be beyond end.  This is
> -			 * only possible in the punch hole case as end is
> -			 * max page offset in the truncate case.
> -			 */
>  			index = page->index;
> -			if (index >= end)
> -				break;
> -
>  			hash = hugetlb_fault_mutex_hash(h, current->mm,
>  							&pseudo_vma,
>  							mapping, index, 0);
> 

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