Commit 0df6db76 authored by Eric Dumazet's avatar Eric Dumazet Committed by Thomas Gleixner
Browse files

posix-timers: Initialize cache early and move pointer into __timer_data 



Move posix_timers_cache initialization to posixtimer_init(). At that point
the memory subsystem is already up and running.

Also move the cache pointer to the __timer_data variable to avoid
potential false sharing, since it never was marked as __ro_after_init.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250402133114.253901-1-edumazet@google.com
parent 0af2f6be

kernel/time/posix-timers.c

+10 −13
Original line number Diff line number Diff line
@@ -30,8 +30,6 @@ 
#include "timekeeping.h"

#include "posix-timers.h"



static struct kmem_cache *posix_timers_cache;



/*

 * Timers are managed in a hash table for lockless lookup. The hash key is

 * constructed from current::signal and the timer ID and the timer is
@@ -49,10 +47,12 @@ struct timer_hash_bucket { 
static struct {

	struct timer_hash_bucket	*buckets;

	unsigned long			mask;

} __timer_data __ro_after_init __aligned(2*sizeof(long));

	struct kmem_cache		*cache;

} __timer_data __ro_after_init __aligned(4*sizeof(long));



#define timer_buckets		(__timer_data.buckets)

#define timer_hashmask		(__timer_data.mask)

#define posix_timers_cache	(__timer_data.cache)



static const struct k_clock * const posix_clocks[];

static const struct k_clock *clockid_to_kclock(const clockid_t id);
@@ -283,14 +283,6 @@ static int posix_get_hrtimer_res(clockid_t which_clock, struct timespec64 *tp) 
	return 0;

}



static __init int init_posix_timers(void)

{

	posix_timers_cache = kmem_cache_create("posix_timers_cache", sizeof(struct k_itimer),

					       __alignof__(struct k_itimer), SLAB_ACCOUNT, NULL);

	return 0;

}

__initcall(init_posix_timers);



/*

 * The siginfo si_overrun field and the return value of timer_getoverrun(2)

 * are of type int. Clamp the overrun value to INT_MAX
@@ -1556,6 +1548,11 @@ static int __init posixtimer_init(void) 
	unsigned long i, size;

	unsigned int shift;



	posix_timers_cache = kmem_cache_create("posix_timers_cache",

					       sizeof(struct k_itimer),

					       __alignof__(struct k_itimer),

					       SLAB_ACCOUNT, NULL);



	if (IS_ENABLED(CONFIG_BASE_SMALL))

		size = 512;

	else