From: Zi Yan <zi.yan@xxxxxxxxxxxxxx>
From: Zi Yan <ziy@xxxxxxxxxx>
Internally, copy_page_mt splits a page into multiple threads
and send them as jobs to system_highpri_wq.
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Zi Yan <zi.yan@xxxxxxxxxxxxxx>
---
include/linux/highmem.h | 2 ++
kernel/sysctl.c | 1 +
mm/Makefile | 2 ++
mm/copy_page.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 101 insertions(+)
create mode 100644 mm/copy_page.c
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index bb3f329..519e575 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -236,6 +236,8 @@ static inline void copy_user_highpage(struct page *to, struct page *from,
#endif
+int copy_page_mt(struct page *to, struct page *from, int nr_pages);
+
static inline void copy_highpage(struct page *to, struct page *from)
{
char *vfrom, *vto;
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 706309f..d54ce12 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -97,6 +97,7 @@
#if defined(CONFIG_SYSCTL)
+
/* External variables not in a header file. */
extern int suid_dumpable;
#ifdef CONFIG_COREDUMP
diff --git a/mm/Makefile b/mm/Makefile
index 295bd7a..467305b 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -41,6 +41,8 @@ obj-y := filemap.o mempool.o oom_kill.o \
obj-y += init-mm.o
+obj-y += copy_page.o
+
ifdef CONFIG_NO_BOOTMEM
obj-y += nobootmem.o
else
diff --git a/mm/copy_page.c b/mm/copy_page.c
new file mode 100644
index 0000000..ca7ce6c
--- /dev/null
+++ b/mm/copy_page.c
@@ -0,0 +1,96 @@
+/*
+ * Parallel page copy routine.
+ *
+ * Zi Yan <ziy@xxxxxxxxxx>
+ *
+ */
+
+#include <linux/highmem.h>
+#include <linux/workqueue.h>
+#include <linux/slab.h>
+#include <linux/freezer.h>
+
+
+const unsigned int limit_mt_num = 4;
+
+/* ======================== multi-threaded copy page ======================== */
+
+struct copy_page_info {
+ struct work_struct copy_page_work;
+ char *to;
+ char *from;
+ unsigned long chunk_size;
+};
+
+static void copy_page_routine(char *vto, char *vfrom,
+ unsigned long chunk_size)
+{
+ memcpy(vto, vfrom, chunk_size);
+}
+
+static void copy_page_work_queue_thread(struct work_struct *work)
+{
+ struct copy_page_info *my_work = (struct copy_page_info *)work;
+
+ copy_page_routine(my_work->to,
+ my_work->from,
+ my_work->chunk_size);
+}
+
+int copy_page_mt(struct page *to, struct page *from, int nr_pages)
+{
+ unsigned int total_mt_num = limit_mt_num;
+ int to_node = page_to_nid(to);
+ int i;
+ struct copy_page_info *work_items;
+ char *vto, *vfrom;
+ unsigned long chunk_size;
+ const struct cpumask *per_node_cpumask = cpumask_of_node(to_node);
+ int cpu_id_list[32] = {0};
+ int cpu;
+
+ total_mt_num = min_t(unsigned int, total_mt_num,
+ cpumask_weight(per_node_cpumask));
+ total_mt_num = (total_mt_num / 2) * 2;
+
+ work_items = kcalloc(total_mt_num, sizeof(struct copy_page_info),
+ GFP_KERNEL);
+ if (!work_items)
+ return -ENOMEM;
+
+ i = 0;
+ for_each_cpu(cpu, per_node_cpumask) {
+ if (i >= total_mt_num)
+ break;
+ cpu_id_list[i] = cpu;
+ ++i;
+ }
+
+ vfrom = kmap(from);
+ vto = kmap(to);
+ chunk_size = PAGE_SIZE*nr_pages / total_mt_num;
+
+ for (i = 0; i < total_mt_num; ++i) {
+ INIT_WORK((struct work_struct *)&work_items[i],
+ copy_page_work_queue_thread);
+
+ work_items[i].to = vto + i * chunk_size;
+ work_items[i].from = vfrom + i * chunk_size;
+ work_items[i].chunk_size = chunk_size;
+
+ queue_work_on(cpu_id_list[i],
+ system_highpri_wq,
+ (struct work_struct *)&work_items[i]);
+ }
+
+ /* Wait until it finishes */
+ for (i = 0; i < total_mt_num; ++i)
+ flush_work((struct work_struct *)&work_items[i]);
+
+ kunmap(to);
+ kunmap(from);
+
+ kfree(work_items);
+
+ return 0;
+}
--
2.10.2
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