From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bob Liu Subject: Re: [PATCH] block: keep bdi->io_pages in sync with max_sectors_kb for stacked devices Date: Mon, 2 Mar 2020 20:16:53 +0800 Message-ID: <7133c4fb-38d5-cf1f-e259-e12b50efcb32@oracle.com> References: <158290150891.4423.13566449569964563258.stgit@buzz> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <158290150891.4423.13566449569964563258.stgit@buzz> Content-Language: en-US Sender: linux-block-owner@vger.kernel.org To: Konstantin Khlebnikov , linux-block@vger.kernel.org, Jens Axboe , linux-kernel@vger.kernel.org Cc: linux-raid@vger.kernel.org, Song Liu , Dmitry Monakhov List-Id: linux-raid.ids On 2/28/20 10:51 PM, Konstantin Khlebnikov wrote: > Field bdi->io_pages added in commit 9491ae4aade6 ("mm: don't cap request > size based on read-ahead setting") removes unneeded split of read requests. > > Stacked drivers do not call blk_queue_max_hw_sectors(). Instead they setup > limits of their devices by blk_set_stacking_limits() + disk_stack_limits(). > Field bio->io_pages stays zero until user set max_sectors_kb via sysfs. > > This patch updates io_pages after merging limits in disk_stack_limits(). > > Commit c6d6e9b0f6b4 ("dm: do not allow readahead to limit IO size") fixed > the same problem for device-mapper devices, this one fixes MD RAIDs. > > Signed-off-by: Konstantin Khlebnikov > --- > block/blk-settings.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/block/blk-settings.c b/block/blk-settings.c > index c8eda2e7b91e..66c45fd79545 100644 > --- a/block/blk-settings.c > +++ b/block/blk-settings.c > @@ -664,6 +664,8 @@ void disk_stack_limits(struct gendisk *disk, struct block_device *bdev, > printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n", > top, bottom); > } > + > + t->backing_dev_info->io_pages = t->limits.max_sectors >> (PAGE_SHIFT-9); > } > EXPORT_SYMBOL(disk_stack_limits); > > Nitpick.. (PAGE_SHIFT - 9) Reviewed-by: Bob Liu