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There are cases when we need to explicitly unroll loops. For example, cache operations, filling DMA descriptors on very high speeds etc. Add compiler-specific attribute macros to give the compiler a hint that we'd like to unroll a loop. Example usage: #define UNROLL_BATCH 8 unrolled_count(UNROLL_BATCH) for (u32 i = 0; i < UNROLL_BATCH; i++) op(priv, i); Note that sometimes the compilers won't unroll loops if they think this would have worse optimization and perf than without unrolling, and that unroll attributes are available only starting GCC 8. For older compiler versions, no hints/attributes will be applied. For better unrolling/parallelization, don't have any variables that interfere between iterations except for the iterator itself. Co-developed-by: Jose E. Marchesi <jose.marchesi@oracle.com> # pragmas Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com> Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com> Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com> Link: https://patch.msgid.link/20250206182630.3914318-2-aleksander.lobakin@intel.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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 reStructuredText 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.