Re: [PATCH] xfs: Use xchg() in xlog_cil_insert_pcp_aggregate()

[Carlos Maiolino]

On Wed, 20 Nov 2024 16:06:22 +0100, Uros Bizjak wrote:
> try_cmpxchg() loop with constant "new" value can be substituted
> with just xchg() to atomically get and clear the location.
> 
> The code on x86_64 improves from:
> 
>     1e7f:	48 89 4c 24 10       	mov    %rcx,0x10(%rsp)
>     1e84:	48 03 14 c5 00 00 00 	add    0x0(,%rax,8),%rdx
>     1e8b:	00
> 			1e88: R_X86_64_32S	__per_cpu_offset
>     1e8c:	8b 02                	mov    (%rdx),%eax
>     1e8e:	41 89 c5             	mov    %eax,%r13d
>     1e91:	31 c9                	xor    %ecx,%ecx
>     1e93:	f0 0f b1 0a          	lock cmpxchg %ecx,(%rdx)
>     1e97:	75 f5                	jne    1e8e <xlog_cil_commit+0x84e>
>     1e99:	48 8b 4c 24 10       	mov    0x10(%rsp),%rcx
>     1e9e:	45 01 e9             	add    %r13d,%r9d
> 
> [...]

Applied to for-next, thanks!

[1/1] xfs: Use xchg() in xlog_cil_insert_pcp_aggregate()
      commit: 214093534f3c046bf5acc9affbf4e6bd9af4538b

Best regards,
-- 
Carlos Maiolino <cem@xxxxxxxxxx>