On 28 March 2015 at 19:14, Peter Zijlstra peterz@infradead.org wrote:
Yeah, something like the below (at the very end) should ensure the thing is cacheline aligned, that should give us a fair few bits.
kernel/time/timer.c | 36 ++++++++---------------------------- 1 file changed, 8 insertions(+), 28 deletions(-)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 2d3f5c504939..c8c45bf50b2e 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -93,6 +93,7 @@ struct tvec_base { struct tvec_base boot_tvec_bases; EXPORT_SYMBOL(boot_tvec_bases); static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases; +static DEFINE_PER_CPU(struct tvec_base, __tvec_bases);
/* Functions below help us manage 'deferrable' flag */ static inline unsigned int tbase_get_deferrable(struct tvec_base *base) @@ -1534,46 +1535,25 @@ EXPORT_SYMBOL(schedule_timeout_uninterruptible);
static int init_timers_cpu(int cpu) {
int j;struct tvec_base *base;
struct tvec_base *base = per_cpu(tvec_bases, cpu); static char tvec_base_done[NR_CPUS];int j; if (!tvec_base_done[cpu]) { static char boot_done;
if (boot_done) {/** The APs use this path later in boot*/base = kzalloc_node(sizeof(*base), GFP_KERNEL,cpu_to_node(cpu));if (!base)return -ENOMEM;/* Make sure tvec_base has TIMER_FLAG_MASK bits free */if (WARN_ON(base != tbase_get_base(base))) {kfree(base);return -ENOMEM;}per_cpu(tvec_bases, cpu) = base;
if (!boot_done) {boot_done = 1; /* skip the boot cpu */ } else {
/** This is for the boot CPU - we use compile-time* static initialisation because per-cpu memory isn't* ready yet and because the memory allocators are not* initialised either.*/boot_done = 1;base = &boot_tvec_bases;
base = per_cpu_ptr(&__tvec_bases);per_cpu(tvec_bases, cpu) = base; }spin_lock_init(&base->lock); tvec_base_done[cpu] = 1; base->cpu = cpu;
} else {base = per_cpu(tvec_bases, cpu); }for (j = 0; j < TVN_SIZE; j++) { INIT_LIST_HEAD(base->tv5.vec + j); INIT_LIST_HEAD(base->tv4.vec + j);
Even after this with following diff gives me the same warning on blackfin..
diff --git a/include/linux/timer.h b/include/linux/timer.h index 8c5a197e1587..58bc28d9cef2 100644 --- a/include/linux/timer.h +++ b/include/linux/timer.h @@ -68,7 +68,7 @@ extern struct tvec_base boot_tvec_bases; #define TIMER_DEFERRABLE 0x1LU #define TIMER_IRQSAFE 0x2LU
-#define TIMER_FLAG_MASK 0x3LU +#define TIMER_FLAG_MASK 0x7LU
#define __TIMER_INITIALIZER(_function, _expires, _data, _flags) { \ .entry = { .prev = TIMER_ENTRY_STATIC }, \
---------x--------------------x----------------------
Warning:
config: blackfin-allyesconfig (attached as .config) reproduce: wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/ma... -O ~/bin/make.cross chmod +x ~/bin/make.cross git checkout ca713e393c6eceb54e803df204772a3d6e6c7981 # save the attached .config to linux build tree make.cross ARCH=blackfin
All error/warnings:
kernel/time/timer.c: In function 'init_timers':
kernel/time/timer.c:1648:2: error: call to '__compiletime_assert_1648' declared with attribute error: BUILD_BUG_ON failed: __alignof__(struct tvec_base) & TIMER_FLAG_MASK