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* xprtrdma: Remove ro_unmap() from all registration modesChuck Lever2016-05-171-12/+0Star
| | | | | | | | | Clean up: The ro_unmap method is no longer used. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Steve Wise <swise@opengridcomputing.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Add ro_unmap_safe memreg methodChuck Lever2016-05-171-0/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | There needs to be a safe method of releasing registered memory resources when an RPC terminates. Safe can mean a number of things: + Doesn't have to sleep + Doesn't rely on having a QP in RTS ro_unmap_safe will be that safe method. It can be used in cases where synchronous memory invalidation can deadlock, or needs to have an active QP. The important case is fencing an RPC's memory regions after it is signaled (^C) and before it exits. If this is not done, there is a window where the server can write an RPC reply into memory that the client has released and re-used for some other purpose. Note that this is a full solution for FRWR, but FMR and physical still have some gaps where a particularly bad server can wreak some havoc on the client. These gaps are not made worse by this patch and are expected to be exceptionally rare and timing-based. They are noted in documenting comments. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Prevent inline overflowChuck Lever2016-05-171-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | When deciding whether to send a Call inline, rpcrdma_marshal_req doesn't take into account header bytes consumed by chunk lists. This results in Call messages on the wire that are sometimes larger than the inline threshold. Likewise, when a Write list or Reply chunk is in play, the server's reply has to emit an RDMA Send that includes a larger-than-minimal RPC-over-RDMA header. The actual size of a Call message cannot be estimated until after the chunk lists have been registered. Thus the size of each RPC-over-RDMA header can be estimated only after chunks are registered; but the decision to register chunks is based on the size of that header. Chicken, meet egg. The best a client can do is estimate header size based on the largest header that might occur, and then ensure that inline content is always smaller than that. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Limit number of RDMA segments in RPC-over-RDMA headersChuck Lever2016-05-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Send buffer space is shared between the RPC-over-RDMA header and an RPC message. A large RPC-over-RDMA header means less space is available for the associated RPC message, which then has to be moved via an RDMA Read or Write. As more segments are added to the chunk lists, the header increases in size. Typical modern hardware needs only a few segments to convey the maximum payload size, but some devices and registration modes may need a lot of segments to convey data payload. Sometimes so many are needed that the remaining space in the Send buffer is not enough for the RPC message. Sending such a message usually fails. To ensure a transport can always make forward progress, cap the number of RDMA segments that are allowed in chunk lists. This prevents less-capable devices and memory registrations from consuming a large portion of the Send buffer by reducing the maximum data payload that can be conveyed with such devices. For now I choose an arbitrary maximum of 8 RDMA segments. This allows a maximum size RPC-over-RDMA header to fit nicely in the current 1024 byte inline threshold with over 700 bytes remaining for an inline RPC message. The current maximum data payload of NFS READ or WRITE requests is one megabyte. To convey that payload on a client with 4KB pages, each chunk segment would need to handle 32 or more data pages. This is well within the capabilities of FMR. For physical registration, the maximum payload size on platforms with 4KB pages is reduced to 32KB. For FRWR, a device's maximum page list depth would need to be at least 34 to support the maximum 1MB payload. A device with a smaller maximum page list depth means the maximum data payload is reduced when using that device. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Steve Wise <swise@opengridcomputing.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Clean up physical_op_map()Chuck Lever2016-03-141-1/+0Star
| | | | | | | | | physical_op_unmap{_sync} don't use mr_nsegs, so don't bother to set it in physical_op_map. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Add ro_unmap_sync method for all-physical registrationChuck Lever2015-12-181-0/+13
| | | | | | | | | | physical's ro_unmap is synchronous already. The new ro_unmap_sync method just has to DMA unmap all MRs associated with the RPC request. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Devesh Sharma <devesh.sharma@avagotech.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Replace global lkey with lkey local to PDChuck Lever2015-09-251-9/+1Star
| | | | | | | | | | | | | | | | | The core API has changed so that devices that do not have a global DMA lkey automatically create an mr, per-PD, and make that lkey available. The global DMA lkey interface is going away in favor of the per-PD DMA lkey. The per-PD DMA lkey is always available. Convert xprtrdma to use the device's per-PD DMA lkey for regbufs, no matter which memory registration scheme is in use. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Sagi Grimberg <sagig@mellanox.com> Cc: linux-nfs <linux-nfs@vger.kernel.org> Acked-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
* xprtrdma: Clean up rpcrdma_ia_open()Chuck Lever2015-08-051-1/+24
| | | | | | | | | | | Untangle the end of rpcrdma_ia_open() by moving DMA MR set-up, which is different for each registration method, to the .ro_open functions. This is refactoring only. No behavior change is expected. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Devesh Sharma <devesh.sharma@avagotech.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Remove ->ro_resetChuck Lever2015-06-121-6/+0Star
| | | | | | | | | | | | | | | | | | | | | An RPC can exit at any time. When it does so, xprt_rdma_free() is called, and it calls ->op_unmap(). If ->ro_reset() is running due to a transport disconnect, the two methods can race while processing the same rpcrdma_mw. The results are unpredictable. Because of this, in previous patches I've altered ->ro_map() to handle MR reset. ->ro_reset() is no longer needed and can be removed. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Steve Wise <swise@opengridcomputing.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Reviewed-by: Devesh Sharma <devesh.sharma@avagotech.com> Tested-By: Devesh Sharma <devesh.sharma@avagotech.com> Reviewed-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Use ib_device pointer safelyChuck Lever2015-06-121-6/+2Star
| | | | | | | | | | | | | | | | | | | | The connect worker can replace ri_id, but prevents ri_id->device from changing during the lifetime of a transport instance. The old ID is kept around until a new ID is created and the ->device is confirmed to be the same. Cache a copy of ri_id->device in rpcrdma_ia and in rpcrdma_rep. The cached copy can be used safely in code that does not serialize with the connect worker. Other code can use it to save an extra address generation (one pointer dereference instead of two). Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Steve Wise <swise@opengridcomputing.com> Tested-By: Devesh Sharma <devesh.sharma@avagotech.com> Reviewed-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Make rpcrdma_{un}map_one() into inline functionsChuck Lever2015-03-311-2/+8
| | | | | | | | | | | | These functions are called in a loop for each page transferred via RDMA READ or WRITE. Extract loop invariants and inline them to reduce CPU overhead. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Devesh Sharma <Devesh.Sharma@Emulex.Com> Tested-by: Meghana Cheripady <Meghana.Cheripady@Emulex.Com> Tested-by: Veeresh U. Kokatnur <veereshuk@chelsio.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Add "open" memreg opChuck Lever2015-03-311-0/+8
| | | | | | | | | | | The open op determines the size of various transport data structures based on device capabilities and memory registration mode. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Devesh Sharma <Devesh.Sharma@Emulex.Com> Tested-by: Meghana Cheripady <Meghana.Cheripady@Emulex.Com> Tested-by: Veeresh U. Kokatnur <veereshuk@chelsio.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Add "destroy MRs" memreg opChuck Lever2015-03-311-0/+6
| | | | | | | | | | | | Memory Region objects associated with a transport instance are destroyed before the instance is shutdown and destroyed. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Tested-by: Devesh Sharma <Devesh.Sharma@Emulex.Com> Tested-by: Meghana Cheripady <Meghana.Cheripady@Emulex.Com> Tested-by: Veeresh U. Kokatnur <veereshuk@chelsio.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Add "reset MRs" memreg opChuck Lever2015-03-311-0/+6
| | | | | | | | | | | | | This method is invoked when a transport instance is about to be reconnected. Each Memory Region object is reset to its initial state. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Tested-by: Devesh Sharma <Devesh.Sharma@Emulex.Com> Tested-by: Meghana Cheripady <Meghana.Cheripady@Emulex.Com> Tested-by: Veeresh U. Kokatnur <veereshuk@chelsio.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Add "init MRs" memreg opChuck Lever2015-03-311-0/+7
| | | | | | | | | | | | | | | | This method is used when setting up a new transport instance to create a pool of Memory Region objects that will be used to register memory during operation. Memory Regions are not needed for "physical" registration, since ->prepare and ->release are no-ops for that mode. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Tested-by: Devesh Sharma <Devesh.Sharma@Emulex.Com> Tested-by: Meghana Cheripady <Meghana.Cheripady@Emulex.Com> Tested-by: Veeresh U. Kokatnur <veereshuk@chelsio.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Add a "deregister_external" op for each memreg modeChuck Lever2015-03-311-0/+10
| | | | | | | | | | | There is very little common processing among the different external memory deregistration functions. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Devesh Sharma <Devesh.Sharma@Emulex.Com> Tested-by: Meghana Cheripady <Meghana.Cheripady@Emulex.Com> Tested-by: Veeresh U. Kokatnur <veereshuk@chelsio.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Add a "register_external" op for each memreg modeChuck Lever2015-03-311-0/+17
| | | | | | | | | | | | | There is very little common processing among the different external memory registration functions. Have rpcrdma_create_chunks() call the registration method directly. This removes a stack frame and a switch statement from the external registration path. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Devesh Sharma <Devesh.Sharma@Emulex.Com> Tested-by: Meghana Cheripady <Meghana.Cheripady@Emulex.Com> Tested-by: Veeresh U. Kokatnur <veereshuk@chelsio.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Add a "max_payload" op for each memreg modeChuck Lever2015-03-311-0/+10
| | | | | | | | | | | | | The max_payload computation is generalized to ensure that the payload maximum is the lesser of RPC_MAX_DATA_SEGS and the number of data segments that can be transmitted in an inline buffer. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Tested-by: Devesh Sharma <Devesh.Sharma@Emulex.Com> Tested-by: Meghana Cheripady <Meghana.Cheripady@Emulex.Com> Tested-by: Veeresh U. Kokatnur <veereshuk@chelsio.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* xprtrdma: Add vector of ops for each memory registration strategyChuck Lever2015-03-311-0/+24
Instead of employing switch() statements, let's use the typical Linux kernel idiom for handling behavioral variation: virtual functions. Start by defining a vector of operations for each supported memory registration mode, and by adding a source file for each mode. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Tested-by: Devesh Sharma <Devesh.Sharma@Emulex.Com> Tested-by: Meghana Cheripady <Meghana.Cheripady@Emulex.Com> Tested-by: Veeresh U. Kokatnur <veereshuk@chelsio.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>