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mm/gup: restrict CMA region by using allocation scope API 

We have well defined scope API to exclude CMA region.  Use it rather than
manipulating gfp_mask manually.  With this change, we can now restore
__GFP_MOVABLE for gfp_mask like as usual migration target allocation.  It
would result in that the ZONE_MOVABLE is also searched by page allocator.
For hugetlb, gfp_mask is redefined since it has a regular allocation mask
filter for migration target.  __GPF_NOWARN is added to hugetlb gfp_mask
filter since a new user for gfp_mask filter, gup, want to be silent when
allocation fails.

Note that this can be considered as a fix for the commit 9a4e9f3b2d
("mm: update get_user_pages_longterm to migrate pages allocated from CMA
region").  However, "Fixes" tag isn't added here since it is just
suboptimal but it doesn't cause any problem.

Suggested-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Link: http://lkml.kernel.org/r/1596180906-8442-1-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joonsoo Kim 2020-08-11 18:37:34 -07:00 committed by Linus Torvalds
parent 8b94e0b8be
commit 41b4dc14ee
2 changed files with 10 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/hugetlb.h
View File

@ -710,6 +710,8 @@ static inline gfp_t htlb_modify_alloc_mask(struct hstate *h, gfp_t gfp_mask)
/* Some callers might want to enforce node */
modified_mask |= (gfp_mask & __GFP_THISNODE);
modified_mask |= (gfp_mask & __GFP_NOWARN);
return modified_mask;
}

17
mm/gup.c
View File

@ -1620,10 +1620,12 @@ static struct page *new_non_cma_page(struct page *page, unsigned long private)
* Trying to allocate a page for migration. Ignore allocation
* failure warnings. We don't force __GFP_THISNODE here because
* this node here is the node where we have CMA reservation and
* in some case these nodes will have really less non movable
* in some case these nodes will have really less non CMA
* allocation memory.
*
* Note that CMA region is prohibited by allocation scope.
*/
gfp_t gfp_mask = GFP_USER | __GFP_NOWARN;
gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_NOWARN;
if (PageHighMem(page))
gfp_mask |= __GFP_HIGHMEM;
@ -1631,6 +1633,8 @@ static struct page *new_non_cma_page(struct page *page, unsigned long private)
#ifdef CONFIG_HUGETLB_PAGE
if (PageHuge(page)) {
struct hstate *h = page_hstate(page);
gfp_mask = htlb_modify_alloc_mask(h, gfp_mask);
/*
* We don't want to dequeue from the pool because pool pages will
* mostly be from the CMA region.
@ -1645,11 +1649,6 @@ static struct page *new_non_cma_page(struct page *page, unsigned long private)
*/
gfp_t thp_gfpmask = GFP_TRANSHUGE | __GFP_NOWARN;
/*
* Remove the movable mask so that we don't allocate from
* CMA area again.
*/
thp_gfpmask &= ~__GFP_MOVABLE;
thp = __alloc_pages_node(nid, thp_gfpmask, HPAGE_PMD_ORDER);
if (!thp)
return NULL;
@ -1795,7 +1794,6 @@ static long __gup_longterm_locked(struct task_struct *tsk,
vmas_tmp, NULL, gup_flags);
if (gup_flags & FOLL_LONGTERM) {
memalloc_nocma_restore(flags);
if (rc < 0)
goto out;
@ -1808,9 +1806,10 @@ static long __gup_longterm_locked(struct task_struct *tsk,
rc = check_and_migrate_cma_pages(tsk, mm, start, rc, pages,
vmas_tmp, gup_flags);
out:
memalloc_nocma_restore(flags);
}
out:
if (vmas_tmp != vmas)
kfree(vmas_tmp);
return rc;