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51d821654b
Interrupt disable/enable trips are quite expensive on x86-64 compared to a
mere cmpxchg (note: no lock prefix!) and percpu counters are used quite
often.
With this change I get a bump of 1% ops/s for negative path lookups,
plugged into will-it-scale:
void testcase(unsigned long long *iterations, unsigned long nr)
{
while (1) {
int fd = open("/tmp/nonexistent", O_RDONLY);
assert(fd == -1);
(*iterations)++;
}
}
The win would be higher if it was not for other slowdowns, but one has
to start somewhere.
Link: https://lkml.kernel.org/r/20240528204257.434817-1-mjguzik@gmail.com
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Dennis Zhou <dennis@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.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.