On 11/22/2016 09:55 PM, Zi Yan wrote:
> From: Zi Yan <zi....@cs.rutgers.edu>
>
> From: Zi Yan <z...@nvidia.com>
>
> Since base page migration did not gain any speedup from
> multi-threaded methods, we only accelerate the huge page case.
>
> Signed-off-by: Zi Yan <z...@nvidia.com>
> Signed-off-by: Zi Yan <zi....@cs.rutgers.edu>
> ---
> kernel/sysctl.c | 11 +++++++++++
> mm/migrate.c | 6 ++++++
> 2 files changed, 17 insertions(+)
>
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index d54ce12..6c79444 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -98,6 +98,8 @@
> #if defined(CONFIG_SYSCTL)
>
>
> +extern int accel_page_copy;
Hmm, accel_mthread_copy because this is achieved by a multi threaded
copy mechanism.
> +
> /* External variables not in a header file. */
> extern int suid_dumpable;
> #ifdef CONFIG_COREDUMP
> @@ -1361,6 +1363,15 @@ static struct ctl_table vm_table[] = {
> .proc_handler = &hugetlb_mempolicy_sysctl_handler,
> },
> #endif
> + {
> + .procname = "accel_page_copy",
> + .data = &accel_page_copy,
> + .maxlen = sizeof(accel_page_copy),
> + .mode = 0644,
> + .proc_handler = proc_dointvec,
> + .extra1 = &zero,
> + .extra2 = &one,
> + },
> {
> .procname = "hugetlb_shm_group",
> .data = &sysctl_hugetlb_shm_group,
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 244ece6..e64b490 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -48,6 +48,8 @@
>
> #include "internal.h"
>
> +int accel_page_copy = 1;
> +
So its enabled by default.
> /*
> * migrate_prep() needs to be called before we start compiling a list of
> pages
> * to be migrated using isolate_lru_page(). If scheduling work on other CPUs
> is
> @@ -651,6 +653,10 @@ static void copy_huge_page(struct page *dst, struct page
> *src,
> nr_pages = hpage_nr_pages(src);
> }
>
> + /* Try to accelerate page migration if it is not specified in mode */
> + if (accel_page_copy)
> + mode |= MIGRATE_MT;
So even if none of the system calls requested for a multi threaded copy,
this setting will override every thing and make it multi threaded.
