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Hao Luo ceac059ed4 bpf: Cache the last valid build_id
For binaries that are statically linked, consecutive stack frames are
likely to be in the same VMA and therefore have the same build id.

On a real-world workload, we observed that 66% of CPU cycles in
__bpf_get_stackid() were spent on build_id_parse() and find_vma().

As an optimization for this case, we can cache the previous frame's
VMA, if the new frame has the same VMA as the previous one, reuse the
previous one's build id.

We are holding the MM locks as reader across the entire loop, so we
don't need to worry about VMA going away.

Tested through "stacktrace_build_id" and "stacktrace_build_id_nmi" in
test_progs.

Suggested-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/bpf/20220224000531.1265030-1-haoluo@google.com
2022-02-28 18:10:28 +01:00
arch bpf, arm64: Support more atomic operations 2022-02-28 16:27:22 +01:00
block block: bio-integrity: Advance seed correctly for larger interval sizes 2022-02-03 21:09:24 -07:00
certs certs: Fix build error when CONFIG_MODULE_SIG_KEY is empty 2022-01-23 00:08:44 +09:00
crypto crypto: af_alg - get rid of alg_memory_allocated 2022-02-15 14:29:04 +00:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-17 11:44:20 -08:00
drivers net/ibmvnic: Cleanup workaround doing an EOI after partition migration 2022-02-18 11:47:48 +00:00
fs fs/file_table: fix adding missing kmemleak_not_leak() 2022-02-17 10:23:19 -08:00
include net: dsa: add support for phylink mac_select_pcs() 2022-02-18 11:28:32 +00:00
init Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2022-02-09 18:40:56 -08:00
ipc ipc/sem: do not sleep with a spin lock held 2022-02-04 09:25:05 -08:00
kernel bpf: Cache the last valid build_id 2022-02-28 18:10:28 +01:00
lib bpf: Add config to allow loading modules with BTF mismatches 2022-02-28 14:17:10 +01:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm: don't try to NUMA-migrate COW pages that have other uses 2022-02-17 08:57:47 -08:00
net ipv6: annotate some data-races around sk->sk_prot 2022-02-18 11:53:28 +00:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-17 11:44:20 -08:00
scripts scripts/pahole-flags.sh: Parse DWARF and generate BTF with multithreading. 2022-02-22 14:32:44 -08:00
security Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-10 17:29:56 -08:00
sound ASoC: Fixes for v5.17 2022-02-01 16:52:54 +01:00
tools libbpf: Fix BPF_MAP_TYPE_PERF_EVENT_ARRAY auto-pinning 2022-02-28 17:20:52 +01:00
usr kbuild: remove include/linux/cyclades.h from header file check 2022-01-27 08:51:08 +01:00
virt Two larger x86 series: 2022-01-28 19:00:26 +02:00
.clang-format genirq/msi: Make interrupt allocation less convoluted 2021-12-16 22:22:20 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: update Christian Brauner's email address 2022-02-01 11:21:31 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Removing Ohad from remoteproc/rpmsg maintenance 2021-12-08 10:09:40 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-17 11:44:20 -08:00
Makefile Linux 5.17-rc4 2022-02-13 12:13:30 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.