[v5,for-next,0/3] IB/core: Obtaining subnet_prefix from cache in

Message

Anand Khoje June 16, 2021, 3:45 p.m. UTC

This v5 patch series is used to read the port_attribute subnet_prefix
from a valid cache entry instead of having to call
device->ops.query_gid() in Infiniband link-layer devices. This requires
addition of a flag used to check that the cache entry is initialized and
that a valid value is being read.

1. Removed the port validity check from ib_get_cached_subnet_prefix.
This check was not useful as the port_num is always valid.

2. Shuffled locks pkey_lost_lock and netdev_lock in struct ib_port_data.
This was done as output of pahole showed two 4-byte holes in the
structure ib_port_data after pkey_list_lock and netdev_lock. Moving
netdev_lock shaved off 8 bytes from the structure.

3. Added a flag to struct ib_port_data. This is used to validate the
status of cached subnet_prefix. This valid cache entry of subnet_prefix
is used in function __ib_query_port().
This allows the utilization of the cache entry and hence avoids a call
into device->ops.query_gid(). We also ensure that in the event of a
cache update, the value for subnet_prefix gets read from the newly updated
GID cache and not via ib_query_port(), so that we do not end up reading a
stale cache value.

Anand Khoje (3):
  IB/core: Removed port validity check from ib_get_cached_subnet_prefix
  IB/core: Shuffle locks in ib_port_data to save memory
  IB/core: Obtain subnet_prefix from cache in IB devices

 drivers/infiniband/core/cache.c     | 21 +++++++++++++--------
 drivers/infiniband/core/core_priv.h |  2 +-
 drivers/infiniband/core/device.c    | 20 +++++++++++---------
 drivers/infiniband/core/security.c  |  7 ++-----
 include/rdma/ib_cache.h             |  1 -
 include/rdma/ib_verbs.h             |  5 ++++-
 6 files changed, 31 insertions(+), 25 deletions(-)

Comments

Jason Gunthorpe June 21, 2021, 11:52 p.m. UTC | #1

On Wed, Jun 16, 2021 at 09:15:06PM +0530, Anand Khoje wrote:
> This v5 patch series is used to read the port_attribute subnet_prefix
> from a valid cache entry instead of having to call
> device->ops.query_gid() in Infiniband link-layer devices. This requires
> addition of a flag used to check that the cache entry is initialized and
> that a valid value is being read.
> 
> 1. Removed the port validity check from ib_get_cached_subnet_prefix.
> This check was not useful as the port_num is always valid.
> 
> 2. Shuffled locks pkey_lost_lock and netdev_lock in struct ib_port_data.
> This was done as output of pahole showed two 4-byte holes in the
> structure ib_port_data after pkey_list_lock and netdev_lock. Moving
> netdev_lock shaved off 8 bytes from the structure.
> 
> 3. Added a flag to struct ib_port_data. This is used to validate the
> status of cached subnet_prefix. This valid cache entry of subnet_prefix
> is used in function __ib_query_port().
> This allows the utilization of the cache entry and hence avoids a call
> into device->ops.query_gid(). We also ensure that in the event of a
> cache update, the value for subnet_prefix gets read from the newly updated
> GID cache and not via ib_query_port(), so that we do not end up reading a
> stale cache value.
> 
> Anand Khoje (3):
>   IB/core: Removed port validity check from ib_get_cached_subnet_prefix
>   IB/core: Shuffle locks in ib_port_data to save memory

I took these two, thanks

Jason