Messages in this thread | | | Subject | Re: [PATCH v4 for-next 3/3] IB/core: Obtain subnet_prefix from cache in IB devices | From | Anand Khoje <> | Date | Wed, 16 Jun 2021 13:12:51 +0530 |
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On 6/16/2021 12:57 PM, Leon Romanovsky wrote: > On Wed, Jun 16, 2021 at 12:22:13PM +0530, Anand Khoje wrote: >> ib_query_port() calls device->ops.query_port() to get the port >> attributes. The method of querying is device driver specific. >> The same function calls device->ops.query_gid() to get the GID and >> extract the subnet_prefix (gid_prefix). >> >> The GID and subnet_prefix are stored in a cache. But they do not get >> read from the cache if the device is an Infiniband device. The >> following change takes advantage of the cached subnet_prefix. >> Testing with RDBMS has shown a significant improvement in performance >> with this change. >> >> The function ib_cache_is_initialised() is introduced because >> ib_query_port() gets called early in the stage when the cache is not >> built while reading port immutable property. >> >> In that case, the default GID still gets read from HCA for IB link- >> layer devices. >> >> In the situation of an event causing cache update, the subnet_prefix >> will get retrieved from newly updated GID cache in ib_cache_update(), >> so that we do not end up reading a stale value from cache via >> ib_query_port(). >> >> Fixes: fad61ad ("IB/core: Add subnet prefix to port info") >> Suggested-by: Leon Romanovsky <leonro@nvidia.com> >> Suggested-by: Aru Kolappan <aru.kolappan@oracle.com> >> Signed-off-by: Anand Khoje <anand.a.khoje@oracle.com> >> Signed-off-by: Haakon Bugge <haakon.bugge@oracle.com> >> --- >> >> v1 -> v2: >> - Split the v1 patch in 3 patches as per Leon's suggestion. >> >> v2 -> v3: >> - Added changes as per Mark Zhang's suggestion of clearing >> flags in git_table_cleanup_one(). >> v3 -> v4: >> - Removed the enum ib_port_data_flags and 8 byte flags from >> struct ib_port_data, and the set_bit()/clear_bit() API >> used to update this flag as that was not necessary. >> Done to keep the code simple. >> - Added code to read subnet_prefix from updated GID cache in the >> event of cache update. Prior to this change, ib_cache_update >> was reading the value for subnet_prefix via ib_query_port(), >> due to this patch, we ended up reading a stale cached value of >> subnet_prefix. >> >> --- >> drivers/infiniband/core/cache.c | 18 +++++++++++++++--- >> drivers/infiniband/core/device.c | 9 +++++++++ >> include/rdma/ib_cache.h | 5 +++++ >> include/rdma/ib_verbs.h | 1 + >> 4 files changed, 30 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/infiniband/core/cache.c b/drivers/infiniband/core/cache.c >> index 2325171..cd99c46 100644 >> --- a/drivers/infiniband/core/cache.c >> +++ b/drivers/infiniband/core/cache.c >> @@ -917,9 +917,11 @@ static void gid_table_cleanup_one(struct ib_device *ib_dev) >> { >> u32 p; >> >> - rdma_for_each_port (ib_dev, p) >> + rdma_for_each_port (ib_dev, p) { >> + ib_dev->port_data[p].cache_is_initialized = 0; > > I think that this line is not needed, we are removing device anyway and > and query_port is not allowed at this stage. > We have kept this for code completeness purposes. Just as we did with set_bit() and clear_bit() APIs.
>> cleanup_gid_table_port(ib_dev, p, >> ib_dev->port_data[p].cache.gid); >> + } >> } >> >> static int gid_table_setup_one(struct ib_device *ib_dev) >> @@ -1466,6 +1468,7 @@ static int config_non_roce_gid_cache(struct ib_device *device, >> struct ib_port_attr *tprops = NULL; >> struct ib_pkey_cache *pkey_cache = NULL; >> struct ib_pkey_cache *old_pkey_cache = NULL; >> + union ib_gid gid; >> int i; >> int ret; >> >> @@ -1523,13 +1526,21 @@ static int config_non_roce_gid_cache(struct ib_device *device, >> device->port_data[port].cache.lmc = tprops->lmc; >> device->port_data[port].cache.port_state = tprops->state; >> >> - device->port_data[port].cache.subnet_prefix = tprops->subnet_prefix; >> + ret = rdma_query_gid(device, port, 0, &gid); >> + if (ret) { >> + write_unlock_irq(&device->cache.lock); >> + goto err; >> + } >> + >> + device->port_data[port].cache.subnet_prefix = >> + be64_to_cpu(gid.global.subnet_prefix); >> + >> write_unlock_irq(&device->cache_lock); >> >> if (enforce_security) >> ib_security_cache_change(device, >> port, >> - tprops->subnet_prefix); >> + be64_to_cpu(gid.global.subnet_prefix)); >> >> kfree(old_pkey_cache); >> kfree(tprops); >> @@ -1629,6 +1640,7 @@ int ib_cache_setup_one(struct ib_device *device) >> err = ib_cache_update(device, p, true, true, true); >> if (err) >> return err; >> + device->port_data[p].cache_is_initialized = 1; >> } >> >> return 0; >> diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c >> index 7a617e4..57b9039 100644 >> --- a/drivers/infiniband/core/device.c >> +++ b/drivers/infiniband/core/device.c >> @@ -2057,6 +2057,15 @@ static int __ib_query_port(struct ib_device *device, >> IB_LINK_LAYER_INFINIBAND) >> return 0; >> >> + if (!ib_cache_is_initialised(device, port_num)) >> + goto query_gid_from_device; > > IMHO, we don't need this new function and can access ib_port_data > directly. In device.c, we have plenty of places that does it. > > Not critical. > Added this function to have a way to check validity of cache, such that it could be used in future for the same check in areas to which ib_port_data is opaque.
>> + >> + ib_get_cached_subnet_prefix(device, port_num, >> + &port_attr->subnet_prefix); >> + >> + return 0; >> + >> +query_gid_from_device: >> err = device->ops.query_gid(device, port_num, 0, &gid); >> if (err) >> return err; >> diff --git a/include/rdma/ib_cache.h b/include/rdma/ib_cache.h >> index 226ae37..46b43a7 100644 >> --- a/include/rdma/ib_cache.h >> +++ b/include/rdma/ib_cache.h >> @@ -114,4 +114,9 @@ ssize_t rdma_query_gid_table(struct ib_device *device, >> struct ib_uverbs_gid_entry *entries, >> size_t max_entries); >> >> +static inline bool ib_cache_is_initialised(struct ib_device *device, >> + u32 port_num) >> +{ >> + return device->port_data[port_num].cache_is_initialized; >> +} >> #endif /* _IB_CACHE_H */ >> diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h >> index c96d601..405f7da 100644 >> --- a/include/rdma/ib_verbs.h >> +++ b/include/rdma/ib_verbs.h >> @@ -2177,6 +2177,7 @@ struct ib_port_data { >> >> spinlock_t netdev_lock; >> >> + u8 cache_is_initialized:1; >> struct list_head pkey_list; >> >> struct ib_port_cache cache; >> -- >> 1.8.3.1 >>
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