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Date:   Fri, 21 Oct 2022 15:22:14 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Chao Leng <lengchao@huawei.com>
Cc:     Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
        Keith Busch <kbusch@kernel.org>,
        Sagi Grimberg <sagi@grimberg.me>,
        Ming Lei <ming.lei@redhat.com>, linux-nvme@lists.infradead.org,
        linux-block@vger.kernel.org
Subject: Re: [PATCH 3/8] blk-mq: move the srcu_struct used for quiescing to
 the tagset
Message-ID: <20221021132214.GC22327@lst.de>
References: <20221020105608.1581940-1-hch@lst.de> <20221020105608.1581940-4-hch@lst.de> <46ce9b02-7474-22a7-f8c2-10f46e88853a@huawei.com>
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On Fri, Oct 21, 2022 at 03:16:50PM +0800, Chao Leng wrote:
>>   	struct list_head	tag_list;
>> +	struct srcu_struct	srcu;
> srcu_struct size is more than 50+ KB, it is waste for the tagset which do not set
> the BLK_MQ_F_BLOCKING, and most tagsets do not set the BLK_MQ_F_BLOCKING.
> Maybe we can define "srcu" as a pointer, and allocate the memory in blk_mq_alloc_tag_set
> just for tagset which set the BLK_MQ_F_BLOCKING.

I guess we could do that.  Still better than the variable sized struct.

p.s. any chance you could properly trim your replies?  I took me a while
to find your comment in the sea of quotes.