The "data" in struct bpf_session_run_ctx is always 8-bytes aligned. Therefore, we can store the "is_return" to the last bit of the "data", which can make bpf_session_run_ctx 8-bytes aligned and save memory.
Signed-off-by: Menglong Dong <[email protected]> --- kernel/trace/bpf_trace.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index f2360579658e..b6a34aa039f6 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2269,7 +2269,6 @@ fs_initcall(bpf_event_init); struct bpf_session_run_ctx { struct bpf_run_ctx run_ctx; - bool is_return; void *data; }; @@ -2535,8 +2534,7 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, { struct bpf_kprobe_multi_run_ctx run_ctx = { .session_ctx = { - .is_return = is_return, - .data = data, + .data = (void *)((unsigned long)data | !!is_return), }, .link = link, .entry_ip = entry_ip, @@ -3058,8 +3056,7 @@ static int uprobe_prog_run(struct bpf_uprobe *uprobe, struct bpf_uprobe_multi_link *link = uprobe->link; struct bpf_uprobe_multi_run_ctx run_ctx = { .session_ctx = { - .is_return = is_return, - .data = data, + .data = (void *)((unsigned long)data | !!is_return), }, .entry_ip = entry_ip, .uprobe = uprobe, @@ -3316,7 +3313,7 @@ __bpf_kfunc bool bpf_session_is_return(void) struct bpf_session_run_ctx *session_ctx; session_ctx = container_of(current->bpf_ctx, struct bpf_session_run_ctx, run_ctx); - return session_ctx->is_return; + return (unsigned long)session_ctx->data & 1; } __bpf_kfunc __u64 *bpf_session_cookie(void) @@ -3324,7 +3321,7 @@ __bpf_kfunc __u64 *bpf_session_cookie(void) struct bpf_session_run_ctx *session_ctx; session_ctx = container_of(current->bpf_ctx, struct bpf_session_run_ctx, run_ctx); - return session_ctx->data; + return (__u64 *)((unsigned long)session_ctx->data & ~1); } __bpf_kfunc_end_defs(); -- 2.51.0
