From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: pasha.tatashin@soleen.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, akpm@linux-foundation.org, vbabka@suse.cz,
mhocko@suse.com, david@redhat.com, osalvador@suse.de,
dan.j.williams@intel.com, sashal@kernel.org,
tyhicks@linux.microsoft.com, iamjoonsoo.kim@lge.com,
mike.kravetz@oracle.com, rostedt@goodmis.org, mingo@redhat.com,
jgg@ziepe.ca, peterz@infradead.org, mgorman@suse.de,
willy@infradead.org, rientjes@google.com, jhubbard@nvidia.com,
linux-doc@vger.kernel.org
Subject: [PATCH v2 7/8] mm/gup: migrate pinned pages out of movable zone
Date: Wed, 9 Dec 2020 19:43:34 -0500 [thread overview]
Message-ID: <20201210004335.64634-8-pasha.tatashin@soleen.com> (raw)
In-Reply-To: <20201210004335.64634-1-pasha.tatashin@soleen.com>
We should not pin pages in ZONE_MOVABLE. Currently, we do not pin only
movable CMA pages. Generalize the function that migrates CMA pages to
migrate all movable pages. Use is_pinnable_page() to check which
pages need to be migrated
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
---
include/linux/migrate.h | 1 +
include/linux/mmzone.h | 11 ++++--
include/trace/events/migrate.h | 3 +-
mm/gup.c | 65 ++++++++++++++--------------------
4 files changed, 37 insertions(+), 43 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/linux/mmzone.h b/include/linux/mmzone.h
index fb3bf696c05e..87a7321b4252 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -405,9 +405,14 @@ enum zone_type {
* likely to succeed, and to locally limit unmovable allocations - e.g.,
* to increase the number of THP/huge pages. Notable special cases are:
*
- * 1. Pinned pages: (long-term) pinning of movable pages might
- * essentially turn such pages unmovable. Memory offlining might
- * retry a long time.
+ * 1. Pinned pages: (long-term) pinning of movable pages is avoided
+ * when pages are pinned and faulted, but it is still possible that
+ * address space already has pages in ZONE_MOVABLE at the time when
+ * pages are pinned (i.e. user has touches that memory before
+ * pinning). In such case we try to migrate them to a different zone,
+ * but if migration fails the pages can still end-up pinned in
+ * ZONE_MOVABLE. In such case, memory offlining might retry a long
+ * time and will only succeed once user application unpins pages.
* 2. memblock allocations: kernelcore/movablecore setups might create
* situations where ZONE_MOVABLE contains unmovable allocations
* after boot. Memory offlining and allocations fail early.
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 0eb8a85fb704..e575237d4c67 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -88,11 +88,12 @@ static __maybe_unused struct page *try_grab_compound_head(struct page *page,
int orig_refs = refs;
/*
- * Can't do FOLL_LONGTERM + FOLL_PIN with CMA in the gup fast
- * path, so fail and let the caller fall back to the slow path.
+ * Can't do FOLL_LONGTERM + FOLL_PIN gup fast path if not in a
+ * right zone, so fail and let the caller fall back to the slow
+ * path.
*/
- if (unlikely(flags & FOLL_LONGTERM) &&
- is_migrate_cma_page(page))
+ if (unlikely((flags & FOLL_LONGTERM) &&
+ !is_pinnable_page(page)))
return NULL;
/*
@@ -1593,19 +1594,18 @@ 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(movable_page_list);
long ret = nr_pages;
struct migration_target_control mtc = {
.nid = NUMA_NO_NODE,
@@ -1623,13 +1623,12 @@ 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_pinnable_page(head)) {
if (PageHuge(head))
- isolate_huge_page(head, &cma_page_list);
+ isolate_huge_page(head, &movable_page_list);
else {
if (!PageLRU(head) && drain_allow) {
lru_add_drain_all();
@@ -1637,7 +1636,7 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm,
}
if (!isolate_lru_page(head)) {
- list_add_tail(&head->lru, &cma_page_list);
+ list_add_tail(&head->lru, &movable_page_list);
mod_node_page_state(page_pgdat(head),
NR_ISOLATED_ANON +
page_is_file_lru(head),
@@ -1649,7 +1648,7 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm,
i += step;
}
- if (!list_empty(&cma_page_list)) {
+ if (!list_empty(&movable_page_list)) {
/*
* drop the above get_user_pages reference.
*/
@@ -1659,7 +1658,7 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm,
for (i = 0; i < nr_pages; i++)
put_page(pages[i]);
- if (migrate_pages(&cma_page_list, alloc_migration_target, NULL,
+ if (migrate_pages(&movable_page_list, alloc_migration_target, NULL,
(unsigned long)&mtc, MIGRATE_SYNC, MR_CONTIG_RANGE)) {
/*
* some of the pages failed migration. Do get_user_pages
@@ -1667,17 +1666,16 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm,
*/
migrate_allow = false;
- if (!list_empty(&cma_page_list))
- putback_movable_pages(&cma_page_list);
+ if (!list_empty(&movable_page_list))
+ putback_movable_pages(&movable_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.
+ * again migrating any pages which we failed to isolate earlier.
*/
ret = __get_user_pages_locked(mm, start, nr_pages,
- pages, vmas, NULL,
- gup_flags);
+ pages, vmas, NULL,
+ gup_flags);
if ((ret > 0) && migrate_allow) {
nr_pages = ret;
@@ -1688,17 +1686,6 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm,
return ret;
}
-#else
-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)
-{
- return nr_pages;
-}
-#endif /* CONFIG_CMA */
/*
* __gup_longterm_locked() is a wrapper for __get_user_pages_locked which
@@ -1746,8 +1733,8 @@ static long __gup_longterm_locked(struct mm_struct *mm,
goto out;
}
- rc = check_and_migrate_cma_pages(mm, start, rc, pages,
- vmas_tmp, gup_flags);
+ rc = check_and_migrate_movable_pages(mm, start, rc, pages,
+ vmas_tmp, gup_flags);
out:
memalloc_pin_restore(flags);
}
--
2.25.1
next prev parent reply other threads:[~2020-12-10 0:43 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-10 0:43 [PATCH v2 0/8] prohibit pinning pages in ZONE_MOVABLE Pavel Tatashin
2020-12-10 0:43 ` [PATCH v2 1/8] mm/gup: perform check_dax_vmas only when FS_DAX is enabled Pavel Tatashin
2020-12-10 6:36 ` Pankaj Gupta
2020-12-10 13:30 ` Pavel Tatashin
2020-12-10 0:43 ` [PATCH v2 2/8] mm/gup: don't pin migrated cma pages in movable zone Pavel Tatashin
2020-12-10 0:43 ` [PATCH v2 3/8] mm/gup: make __gup_longterm_locked common Pavel Tatashin
2020-12-10 4:06 ` Ira Weiny
2020-12-10 13:30 ` Pavel Tatashin
2020-12-10 17:44 ` Ira Weiny
2020-12-10 18:57 ` Pavel Tatashin
2020-12-10 19:53 ` Jason Gunthorpe
2020-12-10 19:54 ` Pavel Tatashin
2020-12-10 0:43 ` [PATCH v2 4/8] mm cma: rename PF_MEMALLOC_NOCMA to PF_MEMALLOC_PIN Pavel Tatashin
2020-12-10 0:43 ` [PATCH v2 5/8] mm: apply per-task gfp constraints in fast path Pavel Tatashin
2020-12-10 0:43 ` [PATCH v2 6/8] mm: honor PF_MEMALLOC_PIN for all movable pages Pavel Tatashin
2020-12-10 0:43 ` Pavel Tatashin [this message]
2020-12-10 0:43 ` [PATCH v2 8/8] memory-hotplug.rst: add a note about ZONE_MOVABLE and page pinning Pavel Tatashin
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