Re: [PATCH v4] libata: Add ATA_HORKAGE_NO_NCQ_ON_AMD for Samsung 860 and 870 SSD.

Kate Hsuan
2021-09-01T09:10:11Z

Hi Hans,

On Wed, Sep 1, 2021 at 5:01 PM Hans de Goede <hdegoede@redhat.com> wrote:
>
> Hi Kate,
>
> On 9/1/21 6:52 AM, Kate Hsuan wrote:
> > Many users are reporting that the Samsung 860 and 870 SSD are having
> > various issues when combined with AMD SATA controllers and only
> > completely disabling NCQ helps to avoid these issues.
> >
> > Always disabling NCQ for Samsung 860/870 SSDs regardless of the host
> > SATA adapter vendor will cause I/O performance degradation with well
> > behaved adapters. To limit the performance impact to AMD adapters,
> > introduce the ATA_HORKAGE_NO_NCQ_ON_AMD flag to force disable NCQ
> > only for these adapters.
> >
> > BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=201693
> > Signed-off-by: Kate Hsuan <hpa@redhat.com>
> > ---
> > Changes in v4:
> > * A function ata_dev_check_adapter() is added to check the vendor ID of
> > the adapter.
> > * ATA_HORKAGE_NONCQ_ON_AMD was modified to ATA_HORKAGE_NO_NCQ_ON_AMD to
> > align with the namingÂ convention.
> > * Commit messages were improved accordingÂ to reviewer comments.

Thanks, I'll fix this.

> >
> > Changes in v3:
> > * ATA_HORKAGE_NONCQ_ON_ASMEDIA_AMD_MARVELL was modified to
> > ATA_HORKAGE_NONCQ_ON_AMD.
> > * Codes were fixed to completely disable NCQ on AMD controller.
> >
> > ---
> > drivers/ata/libata-core.c | 32 ++++++++++++++++++++++++++++++--
> > include/linux/libata.h | 1 +
> > 2 files changed, 31 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> > index c861c93d1e84..49049cd713e4 100644
> > --- a/drivers/ata/libata-core.c
> > +++ b/drivers/ata/libata-core.c
> > @@ -2186,6 +2186,25 @@ static void ata_dev_config_ncq_prio(struct ata_device *dev)
> > dev->flags &= ~ATA_DFLAG_NCQ_PRIO;
> > }
> >
> > +static bool ata_dev_check_adapter(struct ata_device *dev,
> > + unsigned short vendor_id)
> > +{
> > + struct pci_dev *pcidev = NULL;
> > + struct device *parent_dev = NULL;
> > +
> > + for (parent_dev = dev->tdev.parent; parent_dev != NULL;
> > + parent_dev = parent_dev->parent) {
> > + if (dev_is_pci(parent_dev)) {
> > + pcidev = to_pci_dev(parent_dev);
> > + if (pcidev->vendor == vendor_id)
> > + return true;
> > + break;
> > + }
> > + }
> > +
> > + return false;
> > +}
> > +
> > static int ata_dev_config_ncq(struct ata_device *dev,
> > char *desc, size_t desc_sz)
> > {
> > @@ -2204,6 +2223,13 @@ static int ata_dev_config_ncq(struct ata_device *dev,
> > snprintf(desc, desc_sz, "NCQ (not used)");
> > return 0;
> > }
> > +
> > + if (dev->horkage & ATA_HORKAGE_NO_NCQ_ON_AMD &&
> > + ata_dev_check_adapter(dev, PCI_VENDOR_ID_AMD)) {
> > + snprintf(desc, desc_sz, "NCQ (not used)");
> > + return 0;
> > + }
> > +
> > if (ap->flags & ATA_FLAG_NCQ) {
> > hdepth = min(ap->scsi_host->can_queue, ATA_MAX_QUEUE);
> > dev->flags |= ATA_DFLAG_NCQ;
> > @@ -3971,9 +3997,11 @@ static const struct ata_blacklist_entry ata_device_blacklist [] = {
> > { "Samsung SSD 850*", NULL, ATA_HORKAGE_NO_NCQ_TRIM |
> > ATA_HORKAGE_ZERO_AFTER_TRIM, },
> > { "Samsung SSD 860*", NULL, ATA_HORKAGE_NO_NCQ_TRIM |
>
> Something went wrong when you applied my pre-cursor patch to your tree
> as base for this patch, you have spaces in front of and behind the
> "NULL,", where there should be tabs. So this does not apply cleanly
> on top of my patch.
>
> I'll forward my patch to you as an attached .eml file. You should
> "git am <file>.eml" that file on top of the latest linux-block/for-next
> and then rebase your patch on top of that.
>
> > - ATA_HORKAGE_ZERO_AFTER_TRIM, },
> > + ATA_HORKAGE_ZERO_AFTER_TRIM |
> > + ATA_HORKAGE_NO_NCQ_ON_AMD, },
> > { "Samsung SSD 870*", NULL, ATA_HORKAGE_NO_NCQ_TRIM |
>
> Idem for this line.

Got it.

>
> > - ATA_HORKAGE_ZERO_AFTER_TRIM, },
> > + ATA_HORKAGE_ZERO_AFTER_TRIM |
> > + ATA_HORKAGE_NO_NCQ_ON_AMD, },
> > { "FCCT*M500*", NULL, ATA_HORKAGE_NO_NCQ_TRIM |
> > ATA_HORKAGE_ZERO_AFTER_TRIM, },
> >
> > diff --git a/include/linux/libata.h b/include/linux/libata.h
> > index 860e63f5667b..cdc248a15763 100644
> > --- a/include/linux/libata.h
> > +++ b/include/linux/libata.h
> > @@ -426,6 +426,7 @@ enum {
> > ATA_HORKAGE_NOTRIM = (1 << 24), /* don't use TRIM */
> > ATA_HORKAGE_MAX_SEC_1024 = (1 << 25), /* Limit max sects to 1024 */
> > ATA_HORKAGE_MAX_TRIM_128M = (1 << 26), /* Limit max trim size to 128M */
> > + ATA_HORKAGE_NO_NCQ_ON_AMD = (1 << 27), /* Disable NCQ on AMD chipset */
> >
> > /* DMA mask for user DMA control: User visible values; DO NOT
> > renumber */
>
> As discussed elsewhere in this thread, you should allow setting/clearing
> this flag from the libata.force kernel commandline option by adding the
> following extra bit to the patch:
>
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index daa375c7e763..e2e900085f99 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -6136,6 +6136,8 @@ static int __init ata_parse_force_one(char **cur,
> { "ncq", .horkage_off = ATA_HORKAGE_NONCQ },
> { "noncqtrim", .horkage_on = ATA_HORKAGE_NO_NCQ_TRIM },
> { "ncqtrim", .horkage_off = ATA_HORKAGE_NO_NCQ_TRIM },
> + { "noncqamd", .horkage_on = ATA_HORKAGE_NO_NCQ_ON_AMD },
> + { "ncqamd", .horkage_off = ATA_HORKAGE_NO_NCQ_ON_AMD },

I'll add them and propose v5 patch.

> { "dump_id", .horkage_on = ATA_HORKAGE_DUMP_ID },
> { "pio0", .xfer_mask = 1 << (ATA_SHIFT_PIO + 0) },
> { "pio1", .xfer_mask = 1 << (ATA_SHIFT_PIO + 1) },
>
> Regards,
>
> Hans
>

Thank you.

--
BR,
Kate