48be539dd4
rpcrdma_buffer_get acquires an rpcrdma_req and rep for each RPC. Currently this is done in the call_allocate action, and sometimes it can fail if there are many outstanding RPCs. When call_allocate fails, the RPC task is put on the delayq. It is awoken a few milliseconds later, but there's no guarantee it will get a buffer at that time. The RPC task can be repeatedly put back to sleep or even starved. The call_allocate action should rarely fail. The delayq mechanism is not meant to deal with transport congestion. In the current sunrpc stack, there is a friendlier way to deal with this situation. These objects are actually tantamount to an RPC slot (rpc_rqst) and there is a separate FSM action, distinct from call_allocate, for allocating slot resources. This is the call_reserve action. When allocation fails during this action, the RPC is placed on the transport's backlog queue. The backlog mechanism provides a stronger guarantee that when the RPC is awoken, a buffer will be available for it; and backlogged RPCs are awoken one-at-a-time. To make slot resource allocation occur in the call_reserve action, create special ->alloc_slot and ->free_slot call-outs for xprtrdma. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> |
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.