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Date: Tue, 4 Jun 2019 15:26:00 +0800
From: Pingfan Liu <kernelfans@...il.com>
To: linux-mm@...ck.org
Cc: Pingfan Liu <kernelfans@...il.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Ira Weiny <ira.weiny@...el.com>,
Dan Williams <dan.j.williams@...el.com>,
Thomas Gleixner <tglx@...utronix.de>,
Mike Rapoport <rppt@...ux.ibm.com>,
John Hubbard <jhubbard@...dia.com>,
"Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>,
Keith Busch <keith.busch@...el.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH] mm/gup: remove unnecessary check against CMA in __gup_longterm_locked()
The PF_MEMALLOC_NOCMA is set by memalloc_nocma_save(), which is finally
cast to ~_GFP_MOVABLE. So __get_user_pages_locked() will get pages from
non CMA area and pin them. There is no need to
check_and_migrate_cma_pages().
Signed-off-by: Pingfan Liu <kernelfans@...il.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Ira Weiny <ira.weiny@...el.com>
Cc: Dan Williams <dan.j.williams@...el.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Mike Rapoport <rppt@...ux.ibm.com>
Cc: John Hubbard <jhubbard@...dia.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>
Cc: Keith Busch <keith.busch@...el.com>
Cc: linux-kernel@...r.kernel.org
---
mm/gup.c | 146 ---------------------------------------------------------------
1 file changed, 146 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index f173fcb..9d931d1 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1275,149 +1275,6 @@ static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
return false;
}
-#ifdef CONFIG_CMA
-static struct page *new_non_cma_page(struct page *page, unsigned long private)
-{
- /*
- * We want to make sure we allocate the new page from the same node
- * as the source page.
- */
- int nid = page_to_nid(page);
- /*
- * 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
- * allocation memory.
- */
- gfp_t gfp_mask = GFP_USER | __GFP_NOWARN;
-
- if (PageHighMem(page))
- gfp_mask |= __GFP_HIGHMEM;
-
-#ifdef CONFIG_HUGETLB_PAGE
- if (PageHuge(page)) {
- struct hstate *h = page_hstate(page);
- /*
- * We don't want to dequeue from the pool because pool pages will
- * mostly be from the CMA region.
- */
- return alloc_migrate_huge_page(h, gfp_mask, nid, NULL);
- }
-#endif
- if (PageTransHuge(page)) {
- struct page *thp;
- /*
- * ignore allocation failure warnings
- */
- 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;
- prep_transhuge_page(thp);
- return thp;
- }
-
- return __alloc_pages_node(nid, gfp_mask, 0);
-}
-
-static long check_and_migrate_cma_pages(struct task_struct *tsk,
- struct mm_struct *mm,
- unsigned long start,
- unsigned long nr_pages,
- struct page **pages,
- struct vm_area_struct **vmas,
- unsigned int gup_flags)
-{
- long i;
- bool drain_allow = true;
- bool migrate_allow = true;
- LIST_HEAD(cma_page_list);
-
-check_again:
- for (i = 0; i < nr_pages; i++) {
- /*
- * 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 (is_migrate_cma_page(pages[i])) {
-
- struct page *head = compound_head(pages[i]);
-
- if (PageHuge(head)) {
- isolate_huge_page(head, &cma_page_list);
- } else {
- if (!PageLRU(head) && drain_allow) {
- lru_add_drain_all();
- drain_allow = false;
- }
-
- if (!isolate_lru_page(head)) {
- list_add_tail(&head->lru, &cma_page_list);
- mod_node_page_state(page_pgdat(head),
- NR_ISOLATED_ANON +
- page_is_file_cache(head),
- hpage_nr_pages(head));
- }
- }
- }
- }
-
- if (!list_empty(&cma_page_list)) {
- /*
- * drop the above get_user_pages reference.
- */
- for (i = 0; i < nr_pages; i++)
- put_page(pages[i]);
-
- if (migrate_pages(&cma_page_list, new_non_cma_page,
- NULL, 0, MIGRATE_SYNC, MR_CONTIG_RANGE)) {
- /*
- * some of the pages failed migration. Do get_user_pages
- * without migration.
- */
- migrate_allow = false;
-
- if (!list_empty(&cma_page_list))
- putback_movable_pages(&cma_page_list);
- }
- /*
- * We did migrate all the pages, Try to get the page references
- * again migrating any new CMA pages which we failed to isolate
- * earlier.
- */
- nr_pages = __get_user_pages_locked(tsk, mm, start, nr_pages,
- pages, vmas, NULL,
- gup_flags);
-
- if ((nr_pages > 0) && migrate_allow) {
- drain_allow = true;
- goto check_again;
- }
- }
-
- return nr_pages;
-}
-#else
-static long check_and_migrate_cma_pages(struct task_struct *tsk,
- struct mm_struct *mm,
- unsigned long start,
- unsigned long nr_pages,
- struct page **pages,
- struct vm_area_struct **vmas,
- unsigned int gup_flags)
-{
- return nr_pages;
-}
-#endif
-
/*
* __gup_longterm_locked() is a wrapper for __get_user_pages_locked which
* allows us to process the FOLL_LONGTERM flag.
@@ -1462,9 +1319,6 @@ static long __gup_longterm_locked(struct task_struct *tsk,
rc = -EOPNOTSUPP;
goto out;
}
-
- rc = check_and_migrate_cma_pages(tsk, mm, start, rc, pages,
- vmas_tmp, gup_flags);
}
out:
--
2.7.5
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