From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Ming Lei <ming.lei@redhat.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>,
linux-scsi@vger.kernel.org,
"Martin K . Petersen" <martin.petersen@oracle.com>,
linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Bart Van Assche <bvanassche@acm.org>,
"Ewan D . Milne" <emilne@redhat.com>,
Hannes Reinecke <hare@suse.com>, Sagi Grimberg <sagi@grimberg.me>,
Chuck Lever <chuck.lever@oracle.com>,
netdev@vger.kernel.org, linux-nvme@lists.infradead.org
Subject: Re: [PATCH V4 0/3] scsi: core: avoid big pre-allocation for sg list
Date: Mon, 13 May 2019 22:06:13 -0400 [thread overview]
Message-ID: <yq1a7fpg57u.fsf@oracle.com> (raw)
In-Reply-To: <20190428073932.9898-1-ming.lei@redhat.com> (Ming Lei's message of "Sun, 28 Apr 2019 15:39:29 +0800")
Ming,
> Since supporting to blk-mq, big pre-allocation for sg list is
> introduced, this way is very unfriendly wrt. memory consumption.
Applied to 5.3/scsi-queue with some clarifications to the commit
descriptions.
I am not entirely sold on 1 for the inline protection SGL size. NVMe
over PCIe is pretty constrained thanks to the metadata pointer whereas
SCSI DIX uses a real SGL for the PI. Consequently, straddling a page is
not that uncommon for large, sequential I/Os.
But let's try it out. If performance suffers substantially, we may want
to bump it to 2.
--
Martin K. Petersen Oracle Linux Engineering
WARNING: multiple messages have this Message-ID (diff)
From: martin.petersen@oracle.com (Martin K. Petersen)
Subject: [PATCH V4 0/3] scsi: core: avoid big pre-allocation for sg list
Date: Mon, 13 May 2019 22:06:13 -0400 [thread overview]
Message-ID: <yq1a7fpg57u.fsf@oracle.com> (raw)
In-Reply-To: <20190428073932.9898-1-ming.lei@redhat.com> (Ming Lei's message of "Sun, 28 Apr 2019 15:39:29 +0800")
Ming,
> Since supporting to blk-mq, big pre-allocation for sg list is
> introduced, this way is very unfriendly wrt. memory consumption.
Applied to 5.3/scsi-queue with some clarifications to the commit
descriptions.
I am not entirely sold on 1 for the inline protection SGL size. NVMe
over PCIe is pretty constrained thanks to the metadata pointer whereas
SCSI DIX uses a real SGL for the PI. Consequently, straddling a page is
not that uncommon for large, sequential I/Os.
But let's try it out. If performance suffers substantially, we may want
to bump it to 2.
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2019-05-14 2:07 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-28 7:39 [PATCH V4 0/3] scsi: core: avoid big pre-allocation for sg list Ming Lei
2019-04-28 7:39 ` Ming Lei
2019-04-28 7:39 ` [PATCH V4 1/3] lib/sg_pool.c: improve APIs for allocating sg pool Ming Lei
2019-04-28 7:39 ` Ming Lei
2019-04-28 12:04 ` Christoph Hellwig
2019-04-28 12:04 ` Christoph Hellwig
2019-04-28 7:39 ` [PATCH V4 2/3] scsi: core: avoid to pre-allocate big chunk for protection meta data Ming Lei
2019-04-29 18:15 ` Bart Van Assche
2019-04-28 7:39 ` [PATCH V4 3/3] scsi: core: avoid to pre-allocate big chunk for sg list Ming Lei
2019-04-29 18:16 ` Bart Van Assche
2019-06-03 20:44 ` Guenter Roeck
2019-06-04 1:00 ` Ming Lei
2019-06-04 3:49 ` Guenter Roeck
2019-06-04 4:10 ` Ming Lei
2019-06-04 14:51 ` Guenter Roeck
2019-06-04 6:55 ` Ming Lei
2019-05-05 1:10 ` [PATCH V4 0/3] scsi: core: avoid big pre-allocation " Ming Lei
2019-05-05 1:10 ` Ming Lei
2019-05-14 2:06 ` Martin K. Petersen [this message]
2019-05-14 2:06 ` Martin K. Petersen
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