[PATCH] xfs: extsize hints are not unlikely in xfs_bmap_btalloc

[PATCH] xfs: extsize hints are not unlikely in xfs_bmap_btalloc

[Christoph Hellwig]

With COW files they are the hotpath, just like for files with the
extent size hint attribute.  We really shouldn't micro-manage anything
but failure cases with unlikely.

Additionally Arnd Bergmann recently reported that one of these two
unlikely annotations causes link failures together with an upcoming
kernel instrumentation patch, so let's get rid of it ASAP.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/libxfs/xfs_bmap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index ab82dd4..bfc00de 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -3629,7 +3629,7 @@ xfs_bmap_btalloc(
 		align = xfs_get_cowextsz_hint(ap->ip);
 	else if (xfs_alloc_is_userdata(ap->datatype))
 		align = xfs_get_extsz_hint(ap->ip);
-	if (unlikely(align)) {
+	if (align) {
 		error = xfs_bmap_extsize_align(mp, &ap->got, &ap->prev,
 						align, 0, ap->eof, 0, ap->conv,
 						&ap->offset, &ap->length);
@@ -3701,7 +3701,7 @@ xfs_bmap_btalloc(
 		args.minlen = ap->minlen;
 	}
 	/* apply extent size hints if obtained earlier */
-	if (unlikely(align)) {
+	if (align) {
 		args.prod = align;
 		if ((args.mod = (xfs_extlen_t)do_mod(ap->offset, args.prod)))
 			args.mod = (xfs_extlen_t)(args.prod - args.mod);
-- 
2.1.4

Re: [PATCH] xfs: extsize hints are not unlikely in xfs_bmap_btalloc

[Darrick J. Wong]

On Wed, Jan 25, 2017 at 05:56:41PM +0100, Christoph Hellwig wrote:
> With COW files they are the hotpath, just like for files with the
> extent size hint attribute.  We really shouldn't micro-manage anything
> but failure cases with unlikely.
> 
> Additionally Arnd Bergmann recently reported that one of these two
> unlikely annotations causes link failures together with an upcoming
> kernel instrumentation patch, so let's get rid of it ASAP.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Queued up for -rc6;
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
>  fs/xfs/libxfs/xfs_bmap.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index ab82dd4..bfc00de 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -3629,7 +3629,7 @@ xfs_bmap_btalloc(
>  		align = xfs_get_cowextsz_hint(ap->ip);
>  	else if (xfs_alloc_is_userdata(ap->datatype))
>  		align = xfs_get_extsz_hint(ap->ip);
> -	if (unlikely(align)) {
> +	if (align) {
>  		error = xfs_bmap_extsize_align(mp, &ap->got, &ap->prev,
>  						align, 0, ap->eof, 0, ap->conv,
>  						&ap->offset, &ap->length);
> @@ -3701,7 +3701,7 @@ xfs_bmap_btalloc(
>  		args.minlen = ap->minlen;
>  	}
>  	/* apply extent size hints if obtained earlier */
> -	if (unlikely(align)) {
> +	if (align) {
>  		args.prod = align;
>  		if ((args.mod = (xfs_extlen_t)do_mod(ap->offset, args.prod)))
>  			args.mod = (xfs_extlen_t)(args.prod - args.mod);
> -- 
> 2.1.4
> 
> --
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