netdev - Re: [PATCH V4 0/3] scsi: core: avoid big pre-allocation for sg list

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <yq1a7fpg57u.fsf@oracle.com>
Date:   Mon, 13 May 2019 22:06:13 -0400
From:   "Martin K. Petersen" <martin.petersen@...cle.com>
To:     Ming Lei <ming.lei@...hat.com>
Cc:     James Bottomley <James.Bottomley@...senPartnership.com>,
        linux-scsi@...r.kernel.org,
        "Martin K . Petersen" <martin.petersen@...cle.com>,
        linux-block@...r.kernel.org, Christoph Hellwig <hch@....de>,
        Bart Van Assche <bvanassche@....org>,
        "Ewan D . Milne" <emilne@...hat.com>,
        Hannes Reinecke <hare@...e.com>,
        Sagi Grimberg <sagi@...mberg.me>,
        Chuck Lever <chuck.lever@...cle.com>, netdev@...r.kernel.org,
        linux-nvme@...ts.infradead.org
Subject: Re: [PATCH V4 0/3] scsi: core: avoid big pre-allocation for sg list

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