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  1. 07 7月, 2018 5 次提交
    • J
      nfp: bpf: rename umin/umax to umin_src/umax_src · 662c5472
      由 Jiong Wang 提交于 
      The two fields are a copy of umin and umax info of bpf_insn->src_reg
generated by verifier.

Rename to make their meaning clear.
Signed-off-by: NJiong Wang <jiong.wang@netronome.com>
Reviewed-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      662c5472
    • J
      lib: reciprocal_div: implement the improved algorithm on the paper mentioned · 06ae4826
      由 Jiong Wang 提交于 
      The new added "reciprocal_value_adv" implements the advanced version of the
algorithm described in Figure 4.2 of the paper except when
"divisor > (1U << 31)" whose ceil(log2(d)) result will be 32 which then
requires u128 divide on host. The exception case could be easily handled
before calling "reciprocal_value_adv".

The advanced version requires more complex calculation to get the
reciprocal multiplier and other control variables, but then could reduce
the required emulation operations.

It makes no sense to use this advanced version for host divide emulation,
those extra complexities for calculating multiplier etc could completely
waive our saving on emulation operations.

However, it makes sense to use it for JIT divide code generation (for
example eBPF JIT backends) for which we are willing to trade performance of
JITed code with that of host. As shown by the following pseudo code, the
required emulation operations could go down from 6 (the basic version) to 3
or 4.

To use the result of "reciprocal_value_adv", suppose we want to calculate
n/d, the C-style pseudo code will be the following, it could be easily
changed to real code generation for other JIT targets.

  struct reciprocal_value_adv rvalue;
  u8 pre_shift, exp;

  // handle exception case.
  if (d >= (1U << 31)) {
    result = n >= d;
    return;
  }
  rvalue = reciprocal_value_adv(d, 32)
  exp = rvalue.exp;
  if (rvalue.is_wide_m && !(d & 1)) {
    // floor(log2(d & (2^32 -d)))
    pre_shift = fls(d & -d) - 1;
    rvalue = reciprocal_value_adv(d >> pre_shift, 32 - pre_shift);
  } else {
    pre_shift = 0;
  }

  // code generation starts.
  if (imm == 1U << exp) {
    result = n >> exp;
  } else if (rvalue.is_wide_m) {
    // pre_shift must be zero when reached here.
    t = (n * rvalue.m) >> 32;
    result = n - t;
    result >>= 1;
    result += t;
    result >>= rvalue.sh - 1;
  } else {
    if (pre_shift)
      result = n >> pre_shift;
    result = ((u64)result * rvalue.m) >> 32;
    result >>= rvalue.sh;
  }
Signed-off-by: NJiong Wang <jiong.wang@netronome.com>
Reviewed-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      06ae4826
    • R
      bpftool: add bash completion for cgroup tree command · 02000b55
      由 Roman Gushchin 提交于 
      This commit adds a bash completion to the bpftool cgroup tree
command.
Signed-off-by: NRoman Gushchin <guro@fb.com>
Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Quentin Monnet <quentin.monnet@netronome.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Acked-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      02000b55
    • R
      bpftool: document cgroup tree command · 7d31a0a1
      由 Roman Gushchin 提交于 
      Describe cgroup tree command in the corresponding bpftool man page.
Signed-off-by: NRoman Gushchin <guro@fb.com>
Acked-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Cc: Quentin Monnet <quentin.monnet@netronome.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      7d31a0a1
    • R
      bpftool: introduce cgroup tree command · 2058b383
      由 Roman Gushchin 提交于 
      This commit introduces a new bpftool command: cgroup tree.
The idea is to iterate over the whole cgroup tree and print
all attached programs.

I was debugging a bpf/systemd issue, and found, that there is
no simple way to listen all bpf programs attached to cgroups.
I did master something in bash, but after some time got tired of it,
and decided, that adding a dedicated bpftool command could be
a better idea.

So, here it is:
  $ sudo ./bpftool cgroup tree
  CgroupPath
  ID       AttachType      AttachFlags     Name
  /sys/fs/cgroup/system.slice/systemd-machined.service
      18       ingress
      17       egress
  /sys/fs/cgroup/system.slice/systemd-logind.service
      20       ingress
      19       egress
  /sys/fs/cgroup/system.slice/systemd-udevd.service
      16       ingress
      15       egress
  /sys/fs/cgroup/system.slice/systemd-journald.service
      14       ingress
      13       egress
Signed-off-by: NRoman Gushchin <guro@fb.com>
Acked-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Cc: Quentin Monnet <quentin.monnet@netronome.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      2058b383
  3. 06 7月, 2018 3 次提交
  5. 05 7月, 2018 32 次提交