From: Minchan Kim <minchan@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
cgoldswo@codeaurora.org, linux-fsdevel@vger.kernel.org,
willy@infradead.org, mhocko@suse.com, david@redhat.com,
vbabka@suse.cz, viro@zeniv.linux.org.uk, joaodias@google.com,
Minchan Kim <minchan@kernel.org>
Subject: [RFC 2/2] mm: fs: Invalidate BH LRU during page migration
Date: Tue, 16 Feb 2021 09:03:48 -0800 [thread overview]
Message-ID: <20210216170348.1513483-2-minchan@kernel.org> (raw)
In-Reply-To: <20210216170348.1513483-1-minchan@kernel.org>
Pages containing buffer_heads that are in one of the per-CPU
buffer_head LRU caches will be pinned and thus cannot be migrated.
This can prevent CMA allocations from succeeding, which are often used
on platforms with co-processors (such as a DSP) that can only use
physically contiguous memory. It can also prevent memory
hot-unplugging from succeeding, which involves migrating at least
MIN_MEMORY_BLOCK_SIZE bytes of memory, which ranges from 8 MiB to 1
GiB based on the architecture in use.
Correspondingly, invalidate the BH LRU caches before a migration
starts and stop any buffer_head from being cached in the LRU caches,
until migration has finished.
Signed-off-by: Chris Goldsworthy <cgoldswo@codeaurora.org>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
fs/buffer.c | 13 +++++++++++--
include/linux/buffer_head.h | 2 ++
mm/swap.c | 5 ++++-
3 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index 96c7604f69b3..de62e75d0ed0 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -45,6 +45,7 @@
#include <linux/mpage.h>
#include <linux/bit_spinlock.h>
#include <linux/pagevec.h>
+#include <linux/migrate.h>
#include <linux/sched/mm.h>
#include <trace/events/block.h>
#include <linux/fscrypt.h>
@@ -1301,6 +1302,14 @@ static void bh_lru_install(struct buffer_head *bh)
int i;
check_irqs_on();
+ /*
+ * buffer_head in bh_lru could increase refcount of the page
+ * until it will be invalidated. It causes page migraion failure.
+ * Skip putting upcoming bh into bh_lru until migration is done.
+ */
+ if (migrate_pending())
+ return;
+
bh_lru_lock();
b = this_cpu_ptr(&bh_lrus);
@@ -1446,7 +1455,7 @@ EXPORT_SYMBOL(__bread_gfp);
* This doesn't race because it runs in each cpu either in irq
* or with preempt disabled.
*/
-static void invalidate_bh_lru(void *arg)
+void invalidate_bh_lru(void *arg)
{
struct bh_lru *b = &get_cpu_var(bh_lrus);
int i;
@@ -1458,7 +1467,7 @@ static void invalidate_bh_lru(void *arg)
put_cpu_var(bh_lrus);
}
-static bool has_bh_in_lru(int cpu, void *dummy)
+bool has_bh_in_lru(int cpu, void *dummy)
{
struct bh_lru *b = per_cpu_ptr(&bh_lrus, cpu);
int i;
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 6b47f94378c5..3d98bdabaac9 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -194,6 +194,8 @@ void __breadahead_gfp(struct block_device *, sector_t block, unsigned int size,
struct buffer_head *__bread_gfp(struct block_device *,
sector_t block, unsigned size, gfp_t gfp);
void invalidate_bh_lrus(void);
+void invalidate_bh_lru(void *);
+bool has_bh_in_lru(int cpu, void *dummy);
struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
void free_buffer_head(struct buffer_head * bh);
void unlock_buffer(struct buffer_head *bh);
diff --git a/mm/swap.c b/mm/swap.c
index e42c4b4bf2b3..14faf558347b 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -37,6 +37,7 @@
#include <linux/page_idle.h>
#include <linux/local_lock.h>
#include <linux/migrate.h>
+#include <linux/buffer_head.h>
#include "internal.h"
@@ -641,6 +642,7 @@ void lru_add_drain_cpu(int cpu)
pagevec_lru_move_fn(pvec, lru_lazyfree_fn);
activate_page_drain(cpu);
+ invalidate_bh_lru(NULL);
}
/**
@@ -827,7 +829,8 @@ void lru_add_drain_all(void)
pagevec_count(&per_cpu(lru_pvecs.lru_deactivate_file, cpu)) ||
pagevec_count(&per_cpu(lru_pvecs.lru_deactivate, cpu)) ||
pagevec_count(&per_cpu(lru_pvecs.lru_lazyfree, cpu)) ||
- need_activate_page_drain(cpu)) {
+ need_activate_page_drain(cpu) ||
+ has_bh_in_lru(cpu, NULL)) {
INIT_WORK(work, lru_add_drain_per_cpu);
queue_work_on(cpu, mm_percpu_wq, work);
__cpumask_set_cpu(cpu, &has_work);
--
2.30.0.478.g8a0d178c01-goog
next prev parent reply other threads:[~2021-02-16 17:04 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-16 17:03 [RFC 1/2] mm: disable LRU pagevec during the migration temporarily Minchan Kim
2021-02-16 17:03 ` Minchan Kim [this message]
2021-02-16 18:22 ` Matthew Wilcox
2021-02-16 21:30 ` Minchan Kim
2021-02-17 8:59 ` Michal Hocko
2021-02-17 9:50 ` Michal Hocko
2021-02-17 20:51 ` Minchan Kim
2021-02-17 21:11 ` Matthew Wilcox
2021-02-17 21:22 ` Minchan Kim
2021-02-17 20:46 ` Minchan Kim
2021-02-17 21:16 ` Matthew Wilcox
2021-02-17 21:32 ` Minchan Kim
2021-02-18 8:17 ` Michal Hocko
2021-02-18 8:24 ` David Hildenbrand
2021-02-18 15:52 ` Minchan Kim
2021-02-18 16:08 ` Michal Hocko
2021-02-18 16:21 ` Minchan Kim
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