forked from Minki/linux
mainlining shenanigans
9b0dfef475
Since kmalloc() is nowadays [1] guaranteed to return naturally
aligned (i.e., aligned to the size itself) memory for power-of-2
sizes, we don't need to over-allocate the align amount, compute an
aligned address within the allocation, and (for later freeing) also
storing the original pointer [2].
Instead, just round up the length we want to allocate to the alignment
requirements, then round that up to the next power of 2. In theory,
this could allocate up to about twice as much memory as we needed. In
practice, (a) kmalloc() would in most cases anyway return a
power-of-2-sized allocation and (b) with the default values of the
bdRingLen[RT]x fields, the length is already itself a power of 2
greater than the alignment.
So we actually end up saving memory compared to the current
situtation (e.g. for tx, we currently allocate 128+32 bytes, which
kmalloc() likely rounds up to 192 or 256; with this patch, we just
allocate 128 bytes.) Also struct ucc_geth_private becomes a little
smaller.
[1]
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| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| 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 | ||
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.