On 2024/2/28 05:26, Daniel Jordan wrote:
On Thu, Feb 22, 2024 at 10:04:18PM +0800, Gang Li wrote:hugetlb parallelization depends on PADATA, and PADATA depends on SMP. PADATA consists of two distinct functionality: One part is padata_do_multithreaded which disregards order and simply divides tasks into several groups for parallel execution. Hugetlb init parallelization depends on padata_do_multithreaded. The other part is composed of a set of APIs that, while handling data in an out-of-order parallel manner, can eventually return the data with ordered sequence. Currently Only `crypto/pcrypt.c` use them. All users of PADATA of non-SMP case currently only use padata_do_multithreaded. It is easy to implement a serial one in include/linux/padata.h. And it is not necessary to implement another functionality unless the only user of crypto/pcrypt.c does not depend on SMP in the future. Signed-off-by: Gang Li <ligang.bdlg@xxxxxxxxxxxxx> Tested-by: Paul E. McKenney <paulmck@xxxxxxxxxx> --- include/linux/padata.h | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/include/linux/padata.h b/include/linux/padata.h index 8f418711351bc..0146daf344306 100644 --- a/include/linux/padata.h +++ b/include/linux/padata.h @@ -180,10 +180,6 @@ struct padata_instance {#ifdef CONFIG_PADATAextern void __init padata_init(void); -#else -static inline void __init padata_init(void) {} -#endif - extern struct padata_instance *padata_alloc(const char *name); extern void padata_free(struct padata_instance *pinst); extern struct padata_shell *padata_alloc_shell(struct padata_instance *pinst); @@ -194,4 +190,12 @@ extern void padata_do_serial(struct padata_priv *padata); extern void __init padata_do_multithreaded(struct padata_mt_job *job); extern int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type, cpumask_var_t cpumask); +#else +static inline void __init padata_init(void) {} +static inline void __init padata_do_multithreaded(struct padata_mt_job *job) +{An early return here for zero-sized jobs is consistent with the CONFIG_PADATA version and avoids hugetlb_pages_alloc_boot taking a lock and flushing the tlb when there's no work to do.
That's reasonable, thanks! Since it's single-threaded, the lock isn't contested, but tlb does need to be treated with caution.
With that, Acked-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
And thanks again.
+ job->thread_fn(job->start, job->start + job->size, job->fn_arg); +} +#endif + #endif -- 2.20.1
