| Message ID | a9f541d0cedf421f765c77a1fb93d6a979778a88.1730495562.git.christophe.jaillet@wanadoo.fr (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | uprobes: Re-order struct uprobe_task to save some space | expand |
On Fri, 1 Nov 2024 22:13:33 +0100 Christophe JAILLET <christophe.jaillet@wanadoo.fr> wrote: > On x86_64, with allmodconfig, struct uprobe_task is 72 bytes long, with a > hole and some padding. > > /* size: 72, cachelines: 2, members: 7 */ > /* sum members: 64, holes: 1, sum holes: 4 */ > /* padding: 4 */ > /* forced alignments: 1, forced holes: 1, sum forced holes: 4 */ > /* last cacheline: 8 bytes */ > > Reorder the structure to fill the hole and avoid the padding. > > This way, the whole structure fits in a single cacheline and some memory is > saved when it is allocated. > > /* size: 64, cachelines: 1, members: 7 */ > /* forced alignments: 1 */ > Looks good to me. Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Thank you! > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> > --- > Compile tested only > --- > include/linux/uprobes.h | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h > index dbaf04189548..c684a470477f 100644 > --- a/include/linux/uprobes.h > +++ b/include/linux/uprobes.h > @@ -73,6 +73,9 @@ enum uprobe_task_state { > struct uprobe_task { > enum uprobe_task_state state; > > + unsigned int depth; > + struct return_instance *return_instances; > + > union { > struct { > struct arch_uprobe_task autask; > @@ -89,9 +92,6 @@ struct uprobe_task { > unsigned long xol_vaddr; > > struct arch_uprobe *auprobe; > - > - struct return_instance *return_instances; > - unsigned int depth; > }; > > struct return_consumer { > -- > 2.47.0 >
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index dbaf04189548..c684a470477f 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -73,6 +73,9 @@ enum uprobe_task_state { struct uprobe_task { enum uprobe_task_state state; + unsigned int depth; + struct return_instance *return_instances; + union { struct { struct arch_uprobe_task autask; @@ -89,9 +92,6 @@ struct uprobe_task { unsigned long xol_vaddr; struct arch_uprobe *auprobe; - - struct return_instance *return_instances; - unsigned int depth; }; struct return_consumer {
On x86_64, with allmodconfig, struct uprobe_task is 72 bytes long, with a hole and some padding. /* size: 72, cachelines: 2, members: 7 */ /* sum members: 64, holes: 1, sum holes: 4 */ /* padding: 4 */ /* forced alignments: 1, forced holes: 1, sum forced holes: 4 */ /* last cacheline: 8 bytes */ Reorder the structure to fill the hole and avoid the padding. This way, the whole structure fits in a single cacheline and some memory is saved when it is allocated. /* size: 64, cachelines: 1, members: 7 */ /* forced alignments: 1 */ Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> --- Compile tested only --- include/linux/uprobes.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)