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| author | Sergey Gorenko <sergeygo@mellanox.com> | 2018-05-21 18:55:53 +0300 |
|---|---|---|
| committer | Doug Ledford <dledford@redhat.com> | 2018-05-31 13:07:17 -0400 |
| commit | 434dda422cb2d52af4c75857c3f2084fe8f3a2ba (patch) | |
| tree | c19c07db4098bcffea7064859c6187d1fc59294c /drivers/infiniband/ulp/iser/iscsi_iser.c | |
| parent | 01298c0cd49f75bd2f133299d8f2655b533363eb (diff) | |
| download | linux-434dda422cb2d52af4c75857c3f2084fe8f3a2ba.tar.bz2 | |
IB/iser: Do not reduce max_sectors
The iSER driver reduces max_sectors. For example, if you load the
ib_iser module with max_sectors=1024, you will see that
/sys/class/block/<bdev>/queue/max_hw_sectors_kb is 508. It is an
incorrect value. The expected value is (max_sectors * sector_size) /
1024 = 512.
Reducing of max_sectors can cause performance degradation due to
unnecessary splitting of IO requests.
The number of pages per MR has been fixed here, so there is no longer
any need to reduce max_sectors.
Fixes: 9c674815d346 ("IB/iser: Fix max_sectors calculation")
Signed-off-by: Sergey Gorenko <sergeygo@mellanox.com>
Reviewed-by: Israel Rukshin <israelr@mellanox.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Acked-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Diffstat (limited to 'drivers/infiniband/ulp/iser/iscsi_iser.c')
| -rw-r--r-- | drivers/infiniband/ulp/iser/iscsi_iser.c | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c index 0336643c2ed6..9a6434c31db2 100644 --- a/drivers/infiniband/ulp/iser/iscsi_iser.c +++ b/drivers/infiniband/ulp/iser/iscsi_iser.c @@ -665,19 +665,17 @@ iscsi_iser_session_create(struct iscsi_endpoint *ep, goto free_host; } - /* - * FRs or FMRs can only map up to a (device) page per entry, but if the - * first entry is misaligned we'll end up using using two entries - * (head and tail) for a single page worth data, so we have to drop - * one segment from the calculation. - */ - max_fr_sectors = ((shost->sg_tablesize - 1) * PAGE_SIZE) >> 9; + max_fr_sectors = (shost->sg_tablesize * PAGE_SIZE) >> 9; shost->max_sectors = min(iser_max_sectors, max_fr_sectors); iser_dbg("iser_conn %p, sg_tablesize %u, max_sectors %u\n", iser_conn, shost->sg_tablesize, shost->max_sectors); + if (shost->max_sectors < iser_max_sectors) + iser_warn("max_sectors was reduced from %u to %u\n", + iser_max_sectors, shost->max_sectors); + if (cmds_max > max_cmds) { iser_info("cmds_max changed from %u to %u\n", cmds_max, max_cmds); |