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Tue, 7 Jan 2025 07:06:50 +0000 (GMT) Message-ID: Date: Tue, 7 Jan 2025 12:36:49 +0530 Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 05/10] block: don't update BLK_FEAT_POLL in __blk_mq_update_nr_hw_queues To: Christoph Hellwig Cc: Jens Axboe , Damien Le Moal , Ming Lei , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, nbd@other.debian.org, virtualization@lists.linux.dev, linux-scsi@vger.kernel.org, usb-storage@lists.one-eyed-alien.net References: <20250106100645.850445-1-hch@lst.de> <20250106100645.850445-6-hch@lst.de> <4addcb5e-fc88-4a86-a464-cc25d8674267@linux.ibm.com> <20250106110532.GA22062@lst.de> <3fb212e4-8fff-45fc-9cff-f5b5eaff4231@linux.ibm.com> <20250106152708.GA27431@lst.de> Content-Language: en-US From: Nilay Shroff In-Reply-To: <20250106152708.GA27431@lst.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: fjpHHO44d6r9IEMzw536FE7K15i-7J20 X-Proofpoint-ORIG-GUID: fjpHHO44d6r9IEMzw536FE7K15i-7J20 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-15_01,2024-10-11_01,2024-09-30_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=305 spamscore=0 impostorscore=0 adultscore=0 lowpriorityscore=0 malwarescore=0 bulkscore=0 clxscore=1015 mlxscore=0 priorityscore=1501 suspectscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2411120000 definitions=main-2501070056 On 1/6/25 8:57 PM, Christoph Hellwig wrote: > On Mon, Jan 06, 2025 at 05:36:52PM +0530, Nilay Shroff wrote: >> Oh yes, I saw that you moved blk_mq_can_poll() to blk-mq.h and >> made it inline so thought why bdev_can_poll() can't be made inline? > > It can be, but why would you want it to? What do you gain from forcing > the compiler to inline it, when sane compilers with a sane inlining > threshold will do that anyway. Hmm, ok, I was thinking just in case we want to force compiler. What if in case compiler doesn't inline it? However, if we're moving this function to a header then it would be made inline, anyways. > >> BTW, bdev_can_poll() is called from IO fastpath and so making it inline >> may slightly improve performance. >> On another note, I do see that blk_mq_can_poll() is now only called >> from bdev_can_poll(). So you may want to merge these two functions >> in a single call and make that inline. > > I'd rather keep generic block layer logic separate from blk-mq logic. > We tend to do a few direct calls into blk-mq from the core code to > avoid the indirect call overhead, but we should still keep the code > as separate as possible to keep it somewhat modular. > Okay, make sense. Thanks, --Nilay