Fork of alistair23 Linux kernel for reMarkable from https://github.com/alistair23/linux
![]() The tree checker is called many times as it verifies metadata at read/write time. The checks follow a simple pattern: if (error_condition) { report_error(); return -EUCLEAN; } All the error reporting functions are annotated as __cold that is supposed to hint the compiler to move the statement block out of the hot path. This does not seem to happen that often. As the error condition is expected to be false almost always, we can annotate it with 'unlikely' as this satisfies one of the few use cases for the annotation. The expected outcome is a stronger hint to compiler to reorder the checks test jump to exit test jump to exit ... which can be observed in asm of eg. check_dir_item, btrfs_check_chunk_valid, check_root_item or check_leaf. There's a measurable run time improvement reported by Josef, the testing workload went from 655 MiB/s to 677 MiB/s, which is about +3%. There should be no functional changes but some of the conditions have been rewritten to produce more readable result, some lines are longer than 80, for the sake of readability. Signed-off-by: David Sterba <dsterba@suse.com> |
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arch | ||
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.