From b31dc66a54ad986b6b73bdc49c8efc17cbad1833 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 13 Jun 2006 08:26:10 +0200 Subject: [PATCH] Kill PF_SYNCWRITE flag A process flag to indicate whether we are doing sync io is incredibly ugly. It also causes performance problems when one does a lot of async io and then proceeds to sync it. Part of the io will go out as async, and the other part as sync. This causes a disconnect between the previously submitted io and the synced io. For io schedulers such as CFQ, this will cause us lost merges and suboptimal behaviour in scheduling. Remove PF_SYNCWRITE completely from the fsync/msync paths, and let the O_DIRECT path just directly indicate that the writes are sync by using WRITE_SYNC instead. Signed-off-by: Jens Axboe --- fs/buffer.c | 2 -- fs/direct-io.c | 18 ++++++++---------- fs/fs-writeback.c | 2 -- 3 files changed, 8 insertions(+), 14 deletions(-) (limited to 'fs') diff --git a/fs/buffer.c b/fs/buffer.c index 23f1f3a..373bb62 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -331,7 +331,6 @@ long do_fsync(struct file *file, int datasync) goto out; } - current->flags |= PF_SYNCWRITE; ret = filemap_fdatawrite(mapping); /* @@ -346,7 +345,6 @@ long do_fsync(struct file *file, int datasync) err = filemap_fdatawait(mapping); if (!ret) ret = err; - current->flags &= ~PF_SYNCWRITE; out: return ret; } diff --git a/fs/direct-io.c b/fs/direct-io.c index b05d1b2..538fb04 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -162,7 +162,7 @@ static int dio_refill_pages(struct dio *dio) NULL); /* vmas */ up_read(¤t->mm->mmap_sem); - if (ret < 0 && dio->blocks_available && (dio->rw == WRITE)) { + if (ret < 0 && dio->blocks_available && (dio->rw & WRITE)) { struct page *page = ZERO_PAGE(dio->curr_user_address); /* * A memory fault, but the filesystem has some outstanding @@ -535,7 +535,7 @@ static int get_more_blocks(struct dio *dio) map_bh->b_state = 0; map_bh->b_size = fs_count << dio->inode->i_blkbits; - create = dio->rw == WRITE; + create = dio->rw & WRITE; if (dio->lock_type == DIO_LOCKING) { if (dio->block_in_file < (i_size_read(dio->inode) >> dio->blkbits)) @@ -867,7 +867,7 @@ do_holes: loff_t i_size_aligned; /* AKPM: eargh, -ENOTBLK is a hack */ - if (dio->rw == WRITE) { + if (dio->rw & WRITE) { page_cache_release(page); return -ENOTBLK; } @@ -1045,7 +1045,7 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, } } /* end iovec loop */ - if (ret == -ENOTBLK && rw == WRITE) { + if (ret == -ENOTBLK && (rw & WRITE)) { /* * The remaining part of the request will be * be handled by buffered I/O when we return @@ -1089,7 +1089,7 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, if (dio->is_async) { int should_wait = 0; - if (dio->result < dio->size && rw == WRITE) { + if (dio->result < dio->size && (rw & WRITE)) { dio->waiter = current; should_wait = 1; } @@ -1142,7 +1142,7 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, ret = transferred; /* We could have also come here on an AIO file extend */ - if (!is_sync_kiocb(iocb) && rw == WRITE && + if (!is_sync_kiocb(iocb) && (rw & WRITE) && ret >= 0 && dio->result == dio->size) /* * For AIO writes where we have completed the @@ -1194,7 +1194,7 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, int acquire_i_mutex = 0; if (rw & WRITE) - current->flags |= PF_SYNCWRITE; + rw = WRITE_SYNC; if (bdev) bdev_blkbits = blksize_bits(bdev_hardsect_size(bdev)); @@ -1270,7 +1270,7 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, * even for AIO, we need to wait for i/o to complete before * returning in this case. */ - dio->is_async = !is_sync_kiocb(iocb) && !((rw == WRITE) && + dio->is_async = !is_sync_kiocb(iocb) && !((rw & WRITE) && (end > i_size_read(inode))); retval = direct_io_worker(rw, iocb, inode, iov, offset, @@ -1284,8 +1284,6 @@ out: mutex_unlock(&inode->i_mutex); else if (acquire_i_mutex) mutex_lock(&inode->i_mutex); - if (rw & WRITE) - current->flags &= ~PF_SYNCWRITE; return retval; } EXPORT_SYMBOL(__blockdev_direct_IO); diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 6db95cf..031b27a 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -623,7 +623,6 @@ int generic_osync_inode(struct inode *inode, struct address_space *mapping, int int need_write_inode_now = 0; int err2; - current->flags |= PF_SYNCWRITE; if (what & OSYNC_DATA) err = filemap_fdatawrite(mapping); if (what & (OSYNC_METADATA|OSYNC_DATA)) { @@ -636,7 +635,6 @@ int generic_osync_inode(struct inode *inode, struct address_space *mapping, int if (!err) err = err2; } - current->flags &= ~PF_SYNCWRITE; spin_lock(&inode_lock); if ((inode->i_state & I_DIRTY) && -- cgit v1.1