On Wed, Dec 02, 2020 at 12:23:30AM -0500, Pavel Tatashin wrote:
> We do not allocate pin pages in ZONE_MOVABLE, but if pages were already
> allocated before pinning they need to migrated to a different zone.
> Currently, we migrate movable CMA pages only. Generalize the function
> that migrates CMA pages to migrate all movable pages.
>
> Signed-off-by: Pavel Tatashin <pasha.tatas...@soleen.com>
> ---
> include/linux/migrate.h | 1 +
> include/trace/events/migrate.h | 3 +-
> mm/gup.c | 56 +++++++++++++---------------------
> 3 files changed, 24 insertions(+), 36 deletions(-)
>
> diff --git a/include/linux/migrate.h b/include/linux/migrate.h
> index 0f8d1583fa8e..00bab23d1ee5 100644
> --- a/include/linux/migrate.h
> +++ b/include/linux/migrate.h
> @@ -27,6 +27,7 @@ enum migrate_reason {
> MR_MEMPOLICY_MBIND,
> MR_NUMA_MISPLACED,
> MR_CONTIG_RANGE,
> + MR_LONGTERM_PIN,
> MR_TYPES
> };
>
> diff --git a/include/trace/events/migrate.h b/include/trace/events/migrate.h
> index 4d434398d64d..363b54ce104c 100644
> --- a/include/trace/events/migrate.h
> +++ b/include/trace/events/migrate.h
> @@ -20,7 +20,8 @@
> EM( MR_SYSCALL, "syscall_or_cpuset") \
> EM( MR_MEMPOLICY_MBIND, "mempolicy_mbind") \
> EM( MR_NUMA_MISPLACED, "numa_misplaced") \
> - EMe(MR_CONTIG_RANGE, "contig_range")
> + EM( MR_CONTIG_RANGE, "contig_range") \
> + EMe(MR_LONGTERM_PIN, "longterm_pin")
>
> /*
> * First define the enums in the above macros to be exported to userspace
> diff --git a/mm/gup.c b/mm/gup.c
> index 724d8a65e1df..1d511f65f8a7 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -1593,19 +1593,18 @@ static bool check_dax_vmas(struct vm_area_struct
> **vmas, long nr_pages)
> }
> #endif
>
> -#ifdef CONFIG_CMA
> -static long check_and_migrate_cma_pages(struct mm_struct *mm,
> - unsigned long start,
> - unsigned long nr_pages,
> - struct page **pages,
> - struct vm_area_struct **vmas,
> - unsigned int gup_flags)
> +static long check_and_migrate_movable_pages(struct mm_struct *mm,
> + unsigned long start,
> + unsigned long nr_pages,
> + struct page **pages,
> + struct vm_area_struct **vmas,
> + unsigned int gup_flags)
> {
> unsigned long i;
> unsigned long step;
> bool drain_allow = true;
> bool migrate_allow = true;
> - LIST_HEAD(cma_page_list);
> + LIST_HEAD(page_list);
> long ret = nr_pages;
> struct migration_target_control mtc = {
> .nid = NUMA_NO_NODE,
> @@ -1623,13 +1622,12 @@ static long check_and_migrate_cma_pages(struct
> mm_struct *mm,
> */
> step = compound_nr(head) - (pages[i] - head);
> /*
> - * If we get a page from the CMA zone, since we are going to
> - * be pinning these entries, we might as well move them out
> - * of the CMA zone if possible.
> + * If we get a movable page, since we are going to be pinning
> + * these entries, try to move them out if possible.
> */
> - if (is_migrate_cma_page(head)) {
> + if (is_migrate_movable(get_pageblock_migratetype(head))) {
is_migrate_movable() isn't a check for the ZONE. It's a check for the
MIGRATE_TYPE. MIGRATE_TYPE doesn't require hard guarantee for
migration, and, most of memory, including ZONE_NORMAL, is
MIGRATE_MOVABLE. With this code, long term gup would always fails due
to not enough memory. I think that correct change would be
"is_migrate_cma_page(hear) && zone == ZONE_MOVABLE".
Patch #5 also has this problem. Please fix it too.
Thanks.
