netdev - [PATCH bpf-next 0/2] bpf, x64: optimize JIT's pro/epilogue

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Message-Id: <20200929204653.4325-1-maciej.fijalkowski@intel.com>
Date:   Tue, 29 Sep 2020 22:46:51 +0200
From:   Maciej Fijalkowski <maciej.fijalkowski@...el.com>
To:     ast@...nel.org, daniel@...earbox.net
Cc:     bpf@...r.kernel.org, netdev@...r.kernel.org, bjorn.topel@...el.com,
        magnus.karlsson@...el.com,
        Maciej Fijalkowski <maciej.fijalkowski@...el.com>
Subject: [PATCH bpf-next 0/2] bpf, x64: optimize JIT's pro/epilogue

Hi!

This small set can be considered as a followup after recent addition of
support for tailcalls in bpf subprograms and is focused on optimizing
x64 JIT prologue and epilogue sections.

Turns out the popping tail call counter is not needed anymore and %rsp
handling when stack depth is 0 can be skipped.

For longer explanations, please see commit messages.

Thank you,
Maciej

Maciej Fijalkowski (2):
  bpf, x64: drop "pop %rcx" instruction on BPF JIT epilogue
  bpf: x64: do not emit sub/add 0, %rsp when !stack_depth

 arch/x86/net/bpf_jit_comp.c | 35 +++++++++++++++++++++++------------
 1 file changed, 23 insertions(+), 12 deletions(-)

-- 
2.20.1