Messages in this thread Patch in this message | | | Date | Tue, 31 Jan 2012 18:34:16 +0800 | From | Wu Fengguang <> | Subject | Re: [PATCH] fix readahead pipeline break caused by block plug |
| |
I'd like to propose a sister patch on the write part. It may not be as easy to measure any performance impacts of it, but I'll try.
--- Subject: remove plugging at buffered write time Date: Tue Jan 31 18:25:48 CST 2012
Buffered write(2) is not directly tied to IO, so no need to handle plug in generic_file_aio_write().
CC: Jens Axboe <axboe@kernel.dk> CC: Li Shaohua <shaohua.li@intel.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> --- mm/filemap.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- linux-next.orig/mm/filemap.c 2012-01-31 18:23:52.000000000 +0800 +++ linux-next/mm/filemap.c 2012-01-31 18:25:38.000000000 +0800 @@ -2267,6 +2267,7 @@ generic_file_direct_write(struct kiocb * struct file *file = iocb->ki_filp; struct address_space *mapping = file->f_mapping; struct inode *inode = mapping->host; + struct blk_plug plug; ssize_t written; size_t write_len; pgoff_t end; @@ -2301,7 +2302,9 @@ generic_file_direct_write(struct kiocb * } } + blk_start_plug(&plug); written = mapping->a_ops->direct_IO(WRITE, iocb, iov, pos, *nr_segs); + blk_finish_plug(&plug); /* * Finally, try again to invalidate clean pages which might have been @@ -2610,13 +2613,11 @@ ssize_t generic_file_aio_write(struct ki { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; - struct blk_plug plug; ssize_t ret; BUG_ON(iocb->ki_pos != pos); mutex_lock(&inode->i_mutex); - blk_start_plug(&plug); ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos); mutex_unlock(&inode->i_mutex); @@ -2627,7 +2628,6 @@ ssize_t generic_file_aio_write(struct ki if (err < 0 && ret > 0) ret = err; } - blk_finish_plug(&plug); return ret; } EXPORT_SYMBOL(generic_file_aio_write);
| |