From: Christoph Hellwig <hch@lst.de>
To: John Garry <john.g.garry@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
"Michael S. Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Damien Le Moal <dlemoal@kernel.org>,
Keith Busch <kbusch@kernel.org>, Sagi Grimberg <sagi@grimberg.me>,
linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
virtualization@lists.linux.dev, Hannes Reinecke <hare@suse.de>
Subject: Re: [PATCH 04/14] block: use queue_limits_commit_update in queue_max_sectors_store
Date: Tue, 30 Jan 2024 15:43:13 +0100 [thread overview]
Message-ID: <20240130144313.GB32125@lst.de> (raw)
In-Reply-To: <e65301d3-7274-45fa-a64c-5039257aa333@oracle.com>
On Tue, Jan 30, 2024 at 12:14:32PM +0000, John Garry wrote:
> On 28/01/2024 16:58, Christoph Hellwig wrote:
>> Convert queue_max_sectors_store to use queue_limits_commit_update to
>> check and update the max_sectors limit and freeze the queue before
>> doing so to ensure we don't have requests in flight while changing
>> the limits.
>>
>> Note that this removes the previously held queue_lock that doesn't
>> protect against any other reader or writer.
>
> I don't really get why we specifically locked that code segment in
> queue_max_sectors_store() previously. Was it to ensure max_sectors and
> q->disk->bdi->io_pages are always atomically updated?
It's been there basically forever. Back in the day before blk-mq
and lock splitting it might actually have protected something.
next prev parent reply other threads:[~2024-01-30 14:43 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-28 16:57 atomic queue limits updates v2 Christoph Hellwig
2024-01-28 16:58 ` [PATCH 01/14] block: move max_{open,active}_zones to struct queue_limits Christoph Hellwig
2024-01-28 23:32 ` Bart Van Assche
2024-01-29 6:15 ` Christoph Hellwig
2024-01-28 16:58 ` [PATCH 02/14] block: refactor disk_update_readahead Christoph Hellwig
2024-01-29 2:59 ` Bart Van Assche
2024-01-29 6:16 ` Christoph Hellwig
2024-01-28 16:58 ` [PATCH 03/14] block: add an API to atomically update queue limits Christoph Hellwig
2024-01-29 6:11 ` Hannes Reinecke
2024-01-30 11:46 ` John Garry
2024-01-30 14:41 ` Christoph Hellwig
2024-01-30 15:05 ` John Garry
2024-01-28 16:58 ` [PATCH 04/14] block: use queue_limits_commit_update in queue_max_sectors_store Christoph Hellwig
2024-01-30 12:14 ` John Garry
2024-01-30 14:43 ` Christoph Hellwig [this message]
2024-01-28 16:58 ` [PATCH 05/14] block: add a max_user_discard_sectors queue limit Christoph Hellwig
2024-01-29 6:13 ` Hannes Reinecke
2024-01-28 16:58 ` [PATCH 06/14] block: use queue_limits_commit_update in queue_discard_max_store Christoph Hellwig
2024-01-28 16:58 ` [PATCH 07/14] block: pass a queue_limits argument to blk_alloc_queue Christoph Hellwig
2024-01-30 12:48 ` John Garry
2024-01-28 16:58 ` [PATCH 08/14] block: pass a queue_limits argument to blk_mq_init_queue Christoph Hellwig
2024-01-30 12:38 ` John Garry
2024-01-28 16:58 ` [PATCH 09/14] block: pass a queue_limits argument to blk_mq_alloc_disk Christoph Hellwig
2024-01-30 12:52 ` John Garry
2024-01-28 16:58 ` [PATCH 10/14] virtio_blk: split virtblk_probe Christoph Hellwig
2024-01-28 16:58 ` [PATCH 11/14] virtio_blk: pass queue_limits to blk_mq_alloc_disk Christoph Hellwig
2024-01-28 16:58 ` [PATCH 12/14] loop: cleanup loop_config_discard Christoph Hellwig
2024-01-28 16:58 ` [PATCH 13/14] loop: pass queue_limits to blk_mq_alloc_disk Christoph Hellwig
2024-01-28 16:58 ` [PATCH 14/14] loop: use the atomic queue limits update API Christoph Hellwig
-- strict thread matches above, loose matches on Subject: below --
2024-01-31 13:03 atomic queue limits updates v3 Christoph Hellwig
2024-01-31 13:03 ` [PATCH 04/14] block: use queue_limits_commit_update in queue_max_sectors_store Christoph Hellwig
2024-01-31 23:18 ` Chaitanya Kulkarni
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