LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Alexey Dobriyan <adobriyan@gmail.com>
To: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] signal: reorder struct sighand_struct
Date: Fri, 3 May 2019 22:28:00 +0300
Message-ID: <20190503192800.GA18004@avx2> (raw)

struct sighand_struct::siglock field is the most used field by far,
put it first so that is can be accessed without IMM8 or IMM32 encoding
on x86_64.

Space savings (on trimmed down VM test config):

add/remove: 0/0 grow/shrink: 8/68 up/down: 49/-1147 (-1098)
Function                                     old     new   delta
complete_signal                              512     533     +21
do_signalfd4                                 335     346     +11
__cleanup_sighand                             39      43      +4
unhandled_signal                              49      52      +3
prepare_signal                               692     695      +3
ignore_signals                                37      40      +3
__tty_check_change.part                      248     251      +3
ksys_unshare                                 780     781      +1
sighand_ctor                                  33      29      -4
ptrace_trap_notify                            60      56      -4
sigqueue_free                                 98      91      -7
run_posix_cpu_timers                        1389    1382      -7
proc_pid_status                             2448    2441      -7
proc_pid_limits                              344     337      -7
posix_cpu_timer_rearm                        222     215      -7
posix_cpu_timer_get                          249     242      -7
kill_pid_info_as_cred                        243     236      -7
freeze_task                                  197     190      -7
flush_old_exec                              1873    1866      -7
do_task_stat                                3363    3356      -7
do_send_sig_info                              98      91      -7
do_group_exit                                147     140      -7
init_sighand                                2088    2080      -8
do_notify_parent_cldstop                     399     391      -8
signalfd_cleanup                              50      41      -9
do_notify_parent                             557     545     -12
__send_signal                               1029    1017     -12
ptrace_stop                                  590     577     -13
get_signal                                  1576    1563     -13
__lock_task_sighand                          112      99     -13
zap_pid_ns_processes                         391     377     -14
update_rlimit_cpu                             78      64     -14
tty_signal_session_leader                    413     399     -14
tty_open_proc_set_tty                        149     135     -14
tty_jobctrl_ioctl                            936     922     -14
set_cpu_itimer                               339     325     -14
ptrace_resume                                226     212     -14
ptrace_notify                                110      96     -14
proc_clear_tty                                81      67     -14
posix_cpu_timer_del                          229     215     -14
kernel_sigaction                             156     142     -14
getrusage                                    977     963     -14
get_current_tty                               98      84     -14
force_sigsegv                                 89      75     -14
force_sig_info                               205     191     -14
flush_signals                                 83      69     -14
flush_itimer_signals                          85      71     -14
do_timer_create                             1120    1106     -14
do_sigpending                                 88      74     -14
do_signal_stop                               537     523     -14
cgroup_init_fs_context                       644     630     -14
call_usermodehelper_exec_async               402     388     -14
calculate_sigpending                          58      44     -14
__x64_sys_timer_delete                       248     234     -14
__set_current_blocked                         80      66     -14
__ptrace_unlink                              310     296     -14
__ptrace_detach.part                         187     173     -14
send_sigqueue                                362     347     -15
get_cpu_itimer                               214     199     -15
signalfd_poll                                175     159     -16
dequeue_signal                               340     323     -17
do_getitimer                                 192     174     -18
release_task.part                           1060    1040     -20
ptrace_peek_siginfo                          408     387     -21
posix_cpu_timer_set                          827     806     -21
exit_signals                                 437     416     -21
do_sigaction                                 541     520     -21
do_setitimer                                 485     464     -21
disassociate_ctty.part                       545     517     -28
__x64_sys_rt_sigtimedwait                    721     679     -42
__x64_sys_ptrace                            1319    1277     -42
ptrace_request                              1828    1782     -46
signalfd_read                                507     459     -48
wait_consider_task                          2027    1971     -56
do_coredump                                 3672    3616     -56
copy_process.part                           6936    6871     -65

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

 include/linux/sched/signal.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -15,10 +15,10 @@
  */
 
 struct sighand_struct {
-	refcount_t		count;
-	struct k_sigaction	action[_NSIG];
 	spinlock_t		siglock;
+	refcount_t		count;
 	wait_queue_head_t	signalfd_wqh;
+	struct k_sigaction	action[_NSIG];
 };
 
 /*

             reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-03 19:28 Alexey Dobriyan [this message]
2019-05-04 23:33 ` Michal Hocko
2019-05-24  2:11   ` Andrew Morton

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190503192800.GA18004@avx2 \
    --to=adobriyan@gmail.com \
    --cc=akpm@linux-foundation.org \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git
	git clone --mirror https://lore.kernel.org/lkml/10 lkml/git/10.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git