Re: [PATCH v2 2/2] libata-core: do not set dev->max_sectors for LBA48 devices

2016-08-12 Thread Martin K. Petersen
> "Alan" == One Thousand Gnomes writes: Alan, Alan> For older SCSI and especially ATA drives (and it wouldn't surprise Alan> me if it is true of modern ones) there are also huge latency Alan> tradeoffs. Absolutely. Alan> Before you jump up and down about

Re: [PATCH v2 2/2] libata-core: do not set dev->max_sectors for LBA48 devices

2016-08-12 Thread One Thousand Gnomes
> Tom> is totally irrational for a general default. I mean, given that it > Tom> was 1024 (512k), try to double it? Fine. Try to quadruple it? > Tom> Alright. We'll need to deal with some alignment / boundary issue > Tom> (like the typical 65535 vs 65536 case)? Okay let's do it. But > Tom> what's

Re: [PATCH v2 2/2] libata-core: do not set dev->max_sectors for LBA48 devices

2016-08-12 Thread Tom Yan
On 12 August 2016 at 13:18, Tom Yan wrote: > On 12 August 2016 at 10:01, Martin K. Petersen > wrote: >> >> Again, the point of max_hw_sectors and max_dev_sectors is to enforce the >> hard limits of controller and device respectively. Nothing else.

Re: [PATCH v2 2/2] libata-core: do not set dev->max_sectors for LBA48 devices

2016-08-11 Thread Tom Yan
On 12 August 2016 at 10:01, Martin K. Petersen wrote: > > Again, the point of max_hw_sectors and max_dev_sectors is to enforce the > hard limits of controller and device respectively. Nothing else. > Sounds like libata-scsi is doing something wrong then. It should not

Re: [PATCH v2 2/2] libata-core: do not set dev->max_sectors for LBA48 devices

2016-08-11 Thread Tom Yan
On 11 August 2016 at 11:37, Martin K. Petersen wrote: >> "Tom" == Tom Yan writes: > > I don't agree with conflating the optimal transfer size and the maximum > supported ditto. Submitting the largest possible I/O to a device does > not

Re: [PATCH v2 2/2] libata-core: do not set dev->max_sectors for LBA48 devices

2016-08-10 Thread Martin K. Petersen
> "Tom" == Tom Yan writes: Tom, Tom> Now let's just come back to libata. I've thought of reporting dev-> Tom> max_sectors as Optimal Transfer Length in the SATL. However, I am Tom> not sure if it is a safe thing to do, because we set it as high as Tom> 65535 for devices

Re: [PATCH v2 2/2] libata-core: do not set dev->max_sectors for LBA48 devices

2016-08-09 Thread Sergei Shtylyov
Hello. On 08/09/2016 05:45 PM, tom.t...@gmail.com wrote: From: Tom Yan Currently block layer limit max_hw_sectors is set to ATA_MAX_SECTORS_LBA48 (65535), for devices with LBA48 support. However, block layer limit max_sectors (which is the effective one; also adjustable,

[PATCH v2 2/2] libata-core: do not set dev->max_sectors for LBA48 devices

2016-08-09 Thread tom . ty89
From: Tom Yan Currently block layer limit max_hw_sectors is set to ATA_MAX_SECTORS_LBA48 (65535), for devices with LBA48 support. However, block layer limit max_sectors (which is the effective one; also adjustable, upper-bounded by max_hw_sectors) is set to