Re: [PATCH stable 4.9 1/8] x86: bpf_jit: small optimization in emit_bpf_tail_call()

2018-01-29 Thread Willy Tarreau
Hi Eric, On Mon, Jan 29, 2018 at 06:04:30AM -0800, Eric Dumazet wrote: > > If these 4 bytes matter, why not use > > cmpq with an immediate value instead, which saves 2 extra bytes ? : > > > > - the mov above is 11 bytes total : > > > >0: 48 8b 84 d6 78 56 34mov0x12345678(%rsi,%rdx,

Re: [PATCH stable 4.9 1/8] x86: bpf_jit: small optimization in emit_bpf_tail_call()

2018-01-29 Thread Eric Dumazet
On Sun, Jan 28, 2018 at 10:39 PM, Willy Tarreau wrote: > Hi, > > [ replaced stable@ and greg@ by netdev@ as my question below is not > relevant to stable ] > > On Mon, Jan 29, 2018 at 02:48:54AM +0100, Daniel Borkmann wrote: >> From: Eric Dumazet >> >> [ upstream commit 84ccac6e7854ebbfb56d2fc6

Re: [PATCH stable 4.9 1/8] x86: bpf_jit: small optimization in emit_bpf_tail_call()

2018-01-28 Thread Willy Tarreau
Hi, [ replaced stable@ and greg@ by netdev@ as my question below is not relevant to stable ] On Mon, Jan 29, 2018 at 02:48:54AM +0100, Daniel Borkmann wrote: > From: Eric Dumazet > > [ upstream commit 84ccac6e7854ebbfb56d2fc6d5bef9be49bb304c ] > > Saves 4 bytes replacing following instructio