[f2fs-dev] [PATCH] f2fs: fix to mitigate overhead of f2fs_zero_post_eof_page()

[f2fs-dev] [PATCH] f2fs: fix to mitigate overhead of f2fs_zero_post_eof_page()

[Chao Yu via Linux-f2fs-devel]

f2fs_zero_post_eof_page() may cuase more overhead due to invalidate_lock
and page lookup, change as below to mitigate its overhead:
- check new_size before grabbing invalidate_lock
- lookup and invalidate pages only in range of [old_size, new_size]

Fixes: ba8dac350faf ("f2fs: fix to zero post-eof page")
Signed-off-by: Chao Yu <chao@kernel.org>
---
 fs/f2fs/file.c | 36 ++++++++++++++++--------------------
 1 file changed, 16 insertions(+), 20 deletions(-)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 1aae4361d0a8..92538d0113f8 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -35,15 +35,20 @@
 #include <trace/events/f2fs.h>
 #include <uapi/linux/f2fs.h>
 
-static void f2fs_zero_post_eof_page(struct inode *inode, loff_t new_size)
+static void f2fs_zero_post_eof_page(struct inode *inode,
+					loff_t new_size, bool lock)
 {
 	loff_t old_size = i_size_read(inode);
 
 	if (old_size >= new_size)
 		return;
 
+	if (lock)
+		filemap_invalidate_lock(inode->i_mapping);
 	/* zero or drop pages only in range of [old_size, new_size] */
-	truncate_pagecache(inode, old_size);
+	truncate_inode_pages_range(inode->i_mapping, old_size, new_size);
+	if (lock)
+		filemap_invalidate_unlock(inode->i_mapping);
 }
 
 static vm_fault_t f2fs_filemap_fault(struct vm_fault *vmf)
@@ -114,9 +119,7 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf)
 
 	f2fs_bug_on(sbi, f2fs_has_inline_data(inode));
 
-	filemap_invalidate_lock(inode->i_mapping);
-	f2fs_zero_post_eof_page(inode, (folio->index + 1) << PAGE_SHIFT);
-	filemap_invalidate_unlock(inode->i_mapping);
+	f2fs_zero_post_eof_page(inode, (folio->index + 1) << PAGE_SHIFT, true);
 
 	file_update_time(vmf->vma->vm_file);
 	filemap_invalidate_lock_shared(inode->i_mapping);
@@ -1149,7 +1152,7 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		filemap_invalidate_lock(inode->i_mapping);
 
 		if (attr->ia_size > old_size)
-			f2fs_zero_post_eof_page(inode, attr->ia_size);
+			f2fs_zero_post_eof_page(inode, attr->ia_size, false);
 		truncate_setsize(inode, attr->ia_size);
 
 		if (attr->ia_size <= old_size)
@@ -1268,9 +1271,7 @@ static int f2fs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
 	if (ret)
 		return ret;
 
-	filemap_invalidate_lock(inode->i_mapping);
-	f2fs_zero_post_eof_page(inode, offset + len);
-	filemap_invalidate_unlock(inode->i_mapping);
+	f2fs_zero_post_eof_page(inode, offset + len, true);
 
 	pg_start = ((unsigned long long) offset) >> PAGE_SHIFT;
 	pg_end = ((unsigned long long) offset + len) >> PAGE_SHIFT;
@@ -1555,7 +1556,7 @@ static int f2fs_do_collapse(struct inode *inode, loff_t offset, loff_t len)
 	f2fs_down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 	filemap_invalidate_lock(inode->i_mapping);
 
-	f2fs_zero_post_eof_page(inode, offset + len);
+	f2fs_zero_post_eof_page(inode, offset + len, false);
 
 	f2fs_lock_op(sbi);
 	f2fs_drop_extent_tree(inode);
@@ -1678,9 +1679,7 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len,
 	if (ret)
 		return ret;
 
-	filemap_invalidate_lock(mapping);
-	f2fs_zero_post_eof_page(inode, offset + len);
-	filemap_invalidate_unlock(mapping);
+	f2fs_zero_post_eof_page(inode, offset + len, true);
 
 	pg_start = ((unsigned long long) offset) >> PAGE_SHIFT;
 	pg_end = ((unsigned long long) offset + len) >> PAGE_SHIFT;
@@ -1814,7 +1813,7 @@ static int f2fs_insert_range(struct inode *inode, loff_t offset, loff_t len)
 	f2fs_down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 	filemap_invalidate_lock(mapping);
 
-	f2fs_zero_post_eof_page(inode, offset + len);
+	f2fs_zero_post_eof_page(inode, offset + len, false);
 	truncate_pagecache(inode, offset);
 
 	while (!ret && idx > pg_start) {
@@ -1872,9 +1871,7 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset,
 	if (err)
 		return err;
 
-	filemap_invalidate_lock(inode->i_mapping);
-	f2fs_zero_post_eof_page(inode, offset + len);
-	filemap_invalidate_unlock(inode->i_mapping);
+	f2fs_zero_post_eof_page(inode, offset + len, true);
 
 	f2fs_balance_fs(sbi, true);
 
@@ -4922,9 +4919,8 @@ static ssize_t f2fs_write_checks(struct kiocb *iocb, struct iov_iter *from)
 	if (err)
 		return err;
 
-	filemap_invalidate_lock(inode->i_mapping);
-	f2fs_zero_post_eof_page(inode, iocb->ki_pos + iov_iter_count(from));
-	filemap_invalidate_unlock(inode->i_mapping);
+	f2fs_zero_post_eof_page(inode,
+		iocb->ki_pos + iov_iter_count(from), true);
 	return count;
 }
 
-- 
2.49.0



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