Messages in this thread | | | Date | Mon, 13 Jan 2020 10:43:43 +0100 | From | Christian Brauner <> | Subject | Re: [PATCH] kernel/fork: put some fork variables into read-mostly section |
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On Mon, Jan 13, 2020 at 11:23:13AM +0800, qiwuchen55@gmail.com wrote: > From: chenqiwu <chenqiwu@xiaomi.com> > > Since total_forks/nr_threads/max_threads global variables are > frequently used for process fork, putting these variables into > read_mostly section can avoid unnecessary cache line bouncing. > > Signed-off-by: chenqiwu <chenqiwu@xiaomi.com> > --- > kernel/fork.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/kernel/fork.c b/kernel/fork.c > index 0808095..163e152 100644 > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -120,10 +120,10 @@ > /* > * Protected counters by write_lock_irq(&tasklist_lock) > */ > -unsigned long total_forks; /* Handle normal Linux uptimes. */ > -int nr_threads; /* The idle threads do not count.. */ > +unsigned long total_forks __read_mostly; /* Handle normal Linux uptimes. */ > +int nr_threads __read_mostly; /* The idle threads do not count.. */
total_forks is incremented at every ~CLONE_THREAD and nr_threads at CLONE_THREAD I wouldn't exactly say that this qualifies as mostly reading.
> > -static int max_threads; /* tunable limit on nr_threads */ > +static int max_threads __read_mostly; /* tunable limit on nr_threads */
That make sense.
Christian
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