Re: [PATCH dwarves] btf_encoder: use ELF_C_READ_MMAP

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Mon, Oct 14, 2024 at 11:31:42AM +0100, Alan Maguire wrote:
> This reduces peak memory utilization during BTF vmlinux encoding,
> replacing ELF section-sized malloc()s with mmap()s.
> 
> For -j1 peak memory resident set size drops from
> 
>         Maximum resident set size (kbytes): 1069220
> 
> ...to:
> 
>         Maximum resident set size (kbytes): 701888
> 
> ...with this patch.
> 
> For -j8, peak memory resident set size drops from
> 
>         Maximum resident set size (kbytes): 1121172
> 
> ...to:
> 
>         Maximum resident set size (kbytes): 963516

Thanks, applied to perf-tools-next,

- Arnaldo
 
> Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
> ---
>  btf_encoder.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/btf_encoder.c b/btf_encoder.c
> index 5954238..9599faf 100644
> --- a/btf_encoder.c
> +++ b/btf_encoder.c
> @@ -1879,7 +1879,7 @@ static int btf_encoder__tag_kfuncs(struct btf_encoder *encoder)
>  		goto out;
>  	}
>  
> -	elf = elf_begin(fd, ELF_C_READ, NULL);
> +	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
>  	if (elf == NULL) {
>  		elf_error("Cannot update ELF file");
>  		goto out;
> -- 
> 2.43.5