kernel/samples/bpf/Makefile, branch linux-5.1.y

bpf: User program for testing HBM

2019-03-02T18:48:27Z

The program nrm creates a cgroup and attaches a BPF program to the cgroup for testing HBM (Host Bandwidth Manager) for egress traffic. One still needs to create network traffic. This can be done through netesto, netperf or iperf3. A follow-up patch contains a script to create traffic. USAGE: hbm [-d] [-l] [-n ] [-r ] [-s] [-t ] [-w] [-h] [prog] Where: -d Print BPF trace debug buffer -l Also limit flows doing loopback -n <#> To create cgroup "/hbm#" and attach prog. Default is /nrm1 This is convenient when testing HBM in more than 1 cgroup -r Rate limit in Mbps -s Get HBM stats (marked, dropped, etc.) -t Exit after specified seconds (deault is 0) -w Work conserving flag. cgroup can increase its bandwidth beyond the rate limit specified while there is available bandwidth. Current implementation assumes there is only NIC (eth0), but can be extended to support multiple NICs. Currrently only supported for egress. Note, this is just a proof of concept. -h Print this info prog BPF program file name. Name defaults to hbm_out_kern.o More information about HBM can be found in the paper "BPF Host Resource Management" presented at the 2018 Linux Plumbers Conference, Networking Track (http://vger.kernel.org/lpc_net2018_talks/LPC%20BPF%20Network%20Resource%20Paper.pdf) Signed-off-by: Lawrence Brakmo Signed-off-by: Alexei Starovoitov

bpf: Sample HBM BPF program to limit egress bw

2019-03-02T18:48:27Z

A cgroup skb BPF program to limit cgroup output bandwidth. It uses a modified virtual token bucket queue to limit average egress bandwidth. The implementation uses credits instead of tokens. Negative credits imply that queueing would have happened (this is a virtual queue, so no queueing is done by it. However, queueing may occur at the actual qdisc (which is not used for rate limiting). This implementation uses 3 thresholds, one to start marking packets and the other two to drop packets: CREDIT - <--------------------------|------------------------> + | | | 0 | Large pkt | | drop thresh | Small pkt drop Mark threshold thresh The effect of marking depends on the type of packet: a) If the packet is ECN enabled, then the packet is ECN ce marked. The current mark threshold is tuned for DCTCP. c) Else, it is dropped if it is a large packet. If the credit is below the drop threshold, the packet is dropped. Note that dropping a packet through the BPF program does not trigger CWR (Congestion Window Reduction) in TCP packets. A future patch will add support for triggering CWR. This BPF program actually uses 2 drop thresholds, one threshold for larger packets (>= 120 bytes) and another for smaller packets. This protects smaller packets such as SYNs, ACKs, etc. The default bandwidth limit is set at 1Gbps but this can be changed by a user program through a shared BPF map. In addition, by default this BPF program does not limit connections using loopback. This behavior can be overwritten by the user program. There is also an option to calculate some statistics, such as percent of packets marked or dropped, which the user program can access. A latter patch provides such a program (hbm.c) Signed-off-by: Lawrence Brakmo Signed-off-by: Alexei Starovoitov

samples: bpf: use libbpf where easy

2019-02-28T23:53:45Z

Some samples don't really need the magic of bpf_load, switch them to libbpf. v2: - specify program types. Signed-off-by: Jakub Kicinski Reviewed-by: Quentin Monnet Acked-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann

samples: bpf: remove load_sock_ops in favour of bpftool

2019-02-28T23:53:45Z

bpftool can do all the things load_sock_ops used to do, and more. Point users to bpftool instead of maintaining this sample utility. Signed-off-by: Jakub Kicinski Reviewed-by: Quentin Monnet Acked-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann

samples/bpf: convert xdpsock to use libbpf for AF_XDP access

2019-02-25T22:21:42Z

This commit converts the xdpsock sample application to use the AF_XDP functions present in libbpf. This cuts down the size of it by nearly 300 lines of code. The default ring sizes plus the batch size has been increased and the size of the umem area has decreased. This so that the sample application will provide higher throughput. Note also that the shared umem code has been removed from the sample as this is not supported by libbpf at this point in time. Tested-by: Björn Töpel Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann

samples/bpf: Convert XDP samples to libbpf usage

2019-02-01T22:37:51Z

Some of XDP samples that are attaching the bpf program to the interface via libbpf's bpf_set_link_xdp_fd are still using the bpf_load.c for loading and manipulating the ebpf program and maps. Convert them to do this through libbpf usage and remove bpf_load from the picture. While at it remove what looks like debug leftover in xdp_redirect_map_user.c In xdp_redirect_cpu, change the way that the program to be loaded onto interface is chosen - user now needs to pass the program's section name instead of the relative number. In case of typo print out the section names to choose from. Signed-off-by: Maciej Fijalkowski Reviewed-by: Jakub Kicinski Acked-by: Jesper Dangaard Brouer Signed-off-by: Daniel Borkmann

samples/bpf: workaround clang asm goto compilation errors

2019-01-15T19:57:30Z

x86 compilation has required asm goto support since 4.17. Since clang does not support asm goto, at 4.17, Commit b1ae32dbab50 ("x86/cpufeature: Guard asm_volatile_goto usage for BPF compilation") worked around the issue by permitting an alternative implementation without asm goto for clang. At 5.0, more asm goto usages appeared. [yhs@148 x86]$ egrep -r asm_volatile_goto include/asm/cpufeature.h: asm_volatile_goto("1: jmp 6f\n" include/asm/jump_label.h: asm_volatile_goto("1:" include/asm/jump_label.h: asm_volatile_goto("1:" include/asm/rmwcc.h: asm_volatile_goto (fullop "; j" #cc " %l[cc_label]" \ include/asm/uaccess.h: asm_volatile_goto("\n" \ include/asm/uaccess.h: asm_volatile_goto("\n" \ [yhs@148 x86]$ Compiling samples/bpf directories, most bpf programs failed compilation with error messages like: In file included from /home/yhs/work/bpf-next/samples/bpf/xdp_sample_pkts_kern.c:2: In file included from /home/yhs/work/bpf-next/include/linux/ptrace.h:6: In file included from /home/yhs/work/bpf-next/include/linux/sched.h:15: In file included from /home/yhs/work/bpf-next/include/linux/sem.h:5: In file included from /home/yhs/work/bpf-next/include/uapi/linux/sem.h:5: In file included from /home/yhs/work/bpf-next/include/linux/ipc.h:9: In file included from /home/yhs/work/bpf-next/include/linux/refcount.h:72: /home/yhs/work/bpf-next/arch/x86/include/asm/refcount.h:70:9: error: 'asm goto' constructs are not supported yet return GEN_BINARY_SUFFIXED_RMWcc(LOCK_PREFIX "subl", ^ /home/yhs/work/bpf-next/arch/x86/include/asm/rmwcc.h:67:2: note: expanded from macro 'GEN_BINARY_SUFFIXED_RMWcc' __GEN_RMWcc(op " %[val], %[var]\n\t" suffix, var, cc, \ ^ /home/yhs/work/bpf-next/arch/x86/include/asm/rmwcc.h:21:2: note: expanded from macro '__GEN_RMWcc' asm_volatile_goto (fullop "; j" #cc " %l[cc_label]" \ ^ /home/yhs/work/bpf-next/include/linux/compiler_types.h:188:37: note: expanded from macro 'asm_volatile_goto' #define asm_volatile_goto(x...) asm goto(x) Most implementation does not even provide an alternative implementation. And it is also not practical to make changes for each call site. This patch workarounded the asm goto issue by redefining the macro like below: #define asm_volatile_goto(x...) asm volatile("invalid use of asm_volatile_goto") If asm_volatile_goto is not used by bpf programs, which is typically the case, nothing bad will happen. If asm_volatile_goto is used by bpf programs, which is incorrect, the compiler will issue an error since "invalid use of asm_volatile_goto" is not valid assembly codes. With this patch, all bpf programs under samples/bpf can pass compilation. Note that bpf programs under tools/testing/selftests/bpf/ compiled fine as they do not access kernel internal headers. Fixes: e769742d3584 ("Revert "x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs"") Fixes: 18fe58229d80 ("x86, asm: change the GEN_*_RMWcc() macros to not quote the condition") Acked-by: Alexei Starovoitov Signed-off-by: Yonghong Song Signed-off-by: Daniel Borkmann

Merge tag 'kbuild-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2018-12-29T20:03:17Z

Pull Kbuild updates from Masahiro Yamada: "Kbuild core: - remove unneeded $(call cc-option,...) switches - consolidate Clang compiler flags into CLANG_FLAGS - announce the deprecation of SUBDIRS - fix single target build for external module - simplify the dependencies of 'prepare' stage targets - allow fixdep to directly write to .*.cmd files - simplify dependency generation for CONFIG_TRIM_UNUSED_KSYMS - change if_changed_rule to accept multi-line recipe - move .SECONDARY special target to scripts/Kbuild.include - remove redundant 'set -e' - improve parallel execution for CONFIG_HEADERS_CHECK - misc cleanups Treewide fixes and cleanups - set Clang flags correctly for PowerPC boot images - fix UML build error with CONFIG_GCC_PLUGINS - remove unneeded patterns from .gitignore files - refactor firmware/Makefile - remove unneeded rules for *offsets.s - avoid unneeded regeneration of intermediate .s files - clean up ./Kbuild Modpost: - remove unused -M, -K options - fix false positive warnings about section mismatch - use simple devtable lookup instead of linker magic - misc cleanups Coccinelle: - relax boolinit.cocci checks for overall consistency - fix warning messages of boolinit.cocci Other tools: - improve -dirty check of scripts/setlocalversion - add a tool to generate compile_commands.json from .*.cmd files" * tag 'kbuild-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (51 commits) kbuild: remove unused cmd_gentimeconst kbuild: remove $(obj)/ prefixes in ./Kbuild treewide: add intermediate .s files to targets treewide: remove explicit rules for *offsets.s firmware: refactor firmware/Makefile firmware: remove unnecessary patterns from .gitignore scripts: remove unnecessary ihex2fw and check-lc_ctypes from .gitignore um: remove unused filechk_gen_header in Makefile scripts: add a tool to produce a compile_commands.json file kbuild: add -Werror=implicit-int flag unconditionally kbuild: add -Werror=strict-prototypes flag unconditionally kbuild: add -fno-PIE flag unconditionally scripts: coccinelle: Correct warning message scripts: coccinelle: only suggest true/false in files that already use them kbuild: handle part-of-module correctly for *.ll and *.symtypes kbuild: refactor part-of-module kbuild: refactor quiet_modtag kbuild: remove redundant quiet_modtag for $(obj-m) kbuild: refactor Makefile.asm-generic user/Makefile: Fix typo and capitalization in comment section ...

treewide: add intermediate .s files to targets

2018-12-23T01:12:08Z

Avoid unneeded recreation of these in the incremental build. Signed-off-by: Masahiro Yamada

treewide: remove explicit rules for *offsets.s

2018-12-23T01:12:03Z

These explicit rules are unneeded because scripts/Makefile.build provides a pattern rule to create %.s from %.c Signed-off-by: Masahiro Yamada