From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out30-42.freemail.mail.aliyun.com ([115.124.30.42]:47682 "EHLO out30-42.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727826AbfKTJph (ORCPT ); Wed, 20 Nov 2019 04:45:37 -0500 From: Jiufei Xue Subject: [PATCH 2/2] ovl: implement async IO routines Date: Wed, 20 Nov 2019 17:45:26 +0800 Message-Id: <1574243126-59283-3-git-send-email-jiufei.xue@linux.alibaba.com> In-Reply-To: <1574243126-59283-1-git-send-email-jiufei.xue@linux.alibaba.com> References: <1574243126-59283-1-git-send-email-jiufei.xue@linux.alibaba.com> Sender: linux-unionfs-owner@vger.kernel.org To: miklos@szeredi.hu, amir73il@gmail.com Cc: linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org List-ID: A performance regression is observed since linux v4.19 when we do aio test using fio with iodepth 128 on overlayfs. And we found that queue depth of the device is always 1 which is unexpected. After investigation, it is found that commit 16914e6fc7e1 ("ovl: add ovl_read_iter()") and commit 2a92e07edc5e ("ovl: add ovl_write_iter()") use do_iter_readv_writev() to submit requests to real filesystem. Async IOs are converted to sync IOs here and cause performance regression. So implement async IO for stacked reading and writing. Changes since v1: - add a cleanup helper for completion/error handling - handle the case when aio_req allocation failed Signed-off-by: Jiufei Xue --- fs/overlayfs/file.c | 116 +++++++++++++++++++++++++++++++++++++++++------ fs/overlayfs/overlayfs.h | 2 + fs/overlayfs/super.c | 12 ++++- 3 files changed, 114 insertions(+), 16 deletions(-) diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index e235a63..8ba000f 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -11,6 +11,14 @@ #include #include "overlayfs.h" +struct ovl_aio_req { + struct kiocb iocb; + struct kiocb *orig_iocb; + struct fd fd; +}; + +static struct kmem_cache *ovl_aio_request_cachep; + static char ovl_whatisit(struct inode *inode, struct inode *realinode) { if (realinode != ovl_inode_upper(inode)) @@ -225,6 +233,33 @@ static rwf_t ovl_iocb_to_rwf(struct kiocb *iocb) return flags; } +static void ovl_aio_cleanup_handler(struct ovl_aio_req *aio_req) +{ + struct kiocb *iocb = &aio_req->iocb; + struct kiocb *orig_iocb = aio_req->orig_iocb; + + if (iocb->ki_flags & IOCB_WRITE) { + struct inode *inode = file_inode(orig_iocb->ki_filp); + + file_end_write(iocb->ki_filp); + ovl_copyattr(ovl_inode_real(inode), inode); + } + + orig_iocb->ki_pos = iocb->ki_pos; + fdput(aio_req->fd); + kmem_cache_free(ovl_aio_request_cachep, aio_req); +} + +static void ovl_aio_rw_complete(struct kiocb *iocb, long res, long res2) +{ + struct ovl_aio_req *aio_req = container_of(iocb, + struct ovl_aio_req, iocb); + struct kiocb *orig_iocb = aio_req->orig_iocb; + + ovl_aio_cleanup_handler(aio_req); + orig_iocb->ki_complete(orig_iocb, res, res2); +} + static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter) { struct file *file = iocb->ki_filp; @@ -240,14 +275,32 @@ static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter) return ret; old_cred = ovl_override_creds(file_inode(file)->i_sb); - ret = vfs_iter_read(real.file, iter, &iocb->ki_pos, - ovl_iocb_to_rwf(iocb)); + if (is_sync_kiocb(iocb)) { + ret = vfs_iter_read(real.file, iter, &iocb->ki_pos, + ovl_iocb_to_rwf(iocb)); + ovl_file_accessed(file); + fdput(real); + } else { + struct ovl_aio_req *aio_req = kmem_cache_alloc(ovl_aio_request_cachep, + GFP_NOFS); + if (!aio_req) { + ret = -ENOMEM; + fdput(real); + goto out_revert; + } + + aio_req->fd = real; + aio_req->orig_iocb = iocb; + kiocb_clone(&aio_req->iocb, iocb, real.file); + aio_req->iocb.ki_complete = ovl_aio_rw_complete; + ret = vfs_iocb_iter_read(real.file, &aio_req->iocb, iter); + ovl_file_accessed(file); + if (ret != -EIOCBQUEUED) + ovl_aio_cleanup_handler(aio_req); + } +out_revert: revert_creds(old_cred); - ovl_file_accessed(file); - - fdput(real); - return ret; } @@ -275,15 +328,34 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter) old_cred = ovl_override_creds(file_inode(file)->i_sb); file_start_write(real.file); - ret = vfs_iter_write(real.file, iter, &iocb->ki_pos, - ovl_iocb_to_rwf(iocb)); - file_end_write(real.file); - revert_creds(old_cred); - - /* Update size */ - ovl_copyattr(ovl_inode_real(inode), inode); + if (is_sync_kiocb(iocb)) { + ret = vfs_iter_write(real.file, iter, &iocb->ki_pos, + ovl_iocb_to_rwf(iocb)); + file_end_write(real.file); + /* Update size */ + ovl_copyattr(ovl_inode_real(inode), inode); + fdput(real); + } else { + struct ovl_aio_req *aio_req = kmem_cache_alloc(ovl_aio_request_cachep, + GFP_NOFS); + if (!aio_req) { + ret = -ENOMEM; + file_end_write(real.file); + fdput(real); + goto out_revert; + } + + aio_req->fd = real; + aio_req->orig_iocb = iocb; + kiocb_clone(&aio_req->iocb, iocb, real.file); + aio_req->iocb.ki_complete = ovl_aio_rw_complete; + ret = vfs_iocb_iter_write(real.file, &aio_req->iocb, iter); + if (ret != -EIOCBQUEUED) + ovl_aio_cleanup_handler(aio_req); + } - fdput(real); +out_revert: + revert_creds(old_cred); out_unlock: inode_unlock(inode); @@ -651,3 +723,19 @@ static loff_t ovl_remap_file_range(struct file *file_in, loff_t pos_in, .copy_file_range = ovl_copy_file_range, .remap_file_range = ovl_remap_file_range, }; + +int __init ovl_init_aio_request_cache(void) +{ + ovl_aio_request_cachep = kmem_cache_create("ovl_aio_req", + sizeof(struct ovl_aio_req), + 0, SLAB_HWCACHE_ALIGN, NULL); + if (!ovl_aio_request_cachep) + return -ENOMEM; + + return 0; +} + +void ovl_exit_aio_request_cache(void) +{ + kmem_cache_destroy(ovl_aio_request_cachep); +} diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 6934bcf..afd1631 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -416,6 +416,8 @@ struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry, /* file.c */ extern const struct file_operations ovl_file_operations; +int __init ovl_init_aio_request_cache(void); +void ovl_exit_aio_request_cache(void); /* copy_up.c */ int ovl_copy_up(struct dentry *dentry); diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index afbcb11..83cef1f 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -1739,9 +1739,17 @@ static int __init ovl_init(void) if (ovl_inode_cachep == NULL) return -ENOMEM; + err = ovl_init_aio_request_cache(); + if (err) { + kmem_cache_destroy(ovl_inode_cachep); + return -ENOMEM; + } + err = register_filesystem(&ovl_fs_type); - if (err) + if (err) { kmem_cache_destroy(ovl_inode_cachep); + ovl_exit_aio_request_cache(); + } return err; } @@ -1756,7 +1764,7 @@ static void __exit ovl_exit(void) */ rcu_barrier(); kmem_cache_destroy(ovl_inode_cachep); - + ovl_exit_aio_request_cache(); } module_init(ovl_init); -- 1.8.3.1