fb985e278a
When working with SRCU protected xarrays the xarray itself should be the SRCU 'update' point. Instead prefetch is using live as the SRCU update point and this prevents switching the locking design to use the xarray instead. To solve this the prefetch must only read from the xarray once, and hold on to the actual MR pointer for the duration of the async operation. Incrementing num_pending_prefetch delays destruction of the MR, so it is suitable. Prefetch calls directly to the pagefault_mr using the MR pointer and only does a single xarray lookup. All the testing if a MR is prefetchable or not is now done only in the prefetch code and removed from the pagefault critical path. Link: https://lore.kernel.org/r/20191009160934.3143-2-jgg@ziepe.ca Reviewed-by: Artemy Kovalyov <artemyko@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
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.
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.