linux/tools/lib
Magnus Karlsson 2c5935f1b2 libbpf: optimize barrier for XDP socket rings
The full memory barrier in the XDP socket rings on the consumer side
between the load of the data and the store of the consumer ring is
there to protect the store from being executed before the load of the
data. If this was allowed to happen, the producer might overwrite the
data field with a new entry before the consumer got the chance to read
it.

On x86, stores are guaranteed not to be reordered with older loads, so
it does not need a full memory barrier here. A compile time barrier
would be enough. This patch introdcues a new primitive in
libbpf_util.h that implements a new barrier type (libbpf_smp_rwmb)
hindering stores to be reordered with older loads. It is then used in
the XDP socket ring access code in libbpf to improve performance.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-16 20:13:10 -07:00
..
api perf tools: Fix tracing_path_mount proper path 2018-10-16 12:27:46 -03:00
bpf libbpf: optimize barrier for XDP socket rings 2019-04-16 20:13:10 -07:00
lockdep lockdep/lib/tests: Test dynamic key registration 2019-02-28 07:55:48 +01:00
subcmd tools lib subcmd: Don't add the kernel sources to the include path 2018-12-18 12:23:56 -03:00
symbol tools lib symbols: Introduce kallsyms__is_function() 2018-04-26 13:47:14 -03:00
traceevent tools lib traceevent: Fix buffer overflow in arg_eval 2019-02-28 16:06:47 -03:00
bitmap.c tools lib: Add bitmap_and function 2016-08-02 16:33:27 -03:00
find_bit.c lib: optimize cpumask_next_and() 2018-02-06 18:32:44 -08:00
hweight.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rbtree.c tools: Update rbtree implementation 2019-01-25 15:12:09 +01:00
str_error_r.c objtool, perf: Fix GCC 8 -Wrestrict error 2018-03-19 13:51:54 -03:00
string.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vsprintf.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00