From: Zi Yan <z...@nvidia.com>

This prepares for the following patches to provide a user API to
manipulate pages in two memory nodes with the help of memcg.

missing memcg_max_size_node()

Signed-off-by: Zi Yan <z...@nvidia.com>
---
 arch/x86/entry/syscalls/syscall_64.tbl |   1 +
 include/linux/sched/coredump.h         |   1 +
 include/linux/syscalls.h               |   5 ++
 include/uapi/linux/mempolicy.h         |   1 +
 mm/Makefile                            |   1 +
 mm/internal.h                          |   2 +
 mm/memory_manage.c                     | 109 +++++++++++++++++++++++++++++++++
 mm/mempolicy.c                         |   2 +-
 8 files changed, 121 insertions(+), 1 deletion(-)
 create mode 100644 mm/memory_manage.c

diff --git a/arch/x86/entry/syscalls/syscall_64.tbl 
b/arch/x86/entry/syscalls/syscall_64.tbl
index 863a21e..fa8def3 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -344,6 +344,7 @@
 333    common  io_pgetevents           __x64_sys_io_pgetevents
 334    common  rseq                    __x64_sys_rseq
 335    common  exchange_pages  __x64_sys_exchange_pages
+336    common  mm_manage               __x64_sys_mm_manage
 # don't use numbers 387 through 423, add new calls after the last
 # 'common' entry
 424    common  pidfd_send_signal       __x64_sys_pidfd_send_signal
diff --git a/include/linux/sched/coredump.h b/include/linux/sched/coredump.h
index ecdc654..9aa9d94b 100644
--- a/include/linux/sched/coredump.h
+++ b/include/linux/sched/coredump.h
@@ -73,6 +73,7 @@ static inline int get_dumpable(struct mm_struct *mm)
 #define MMF_OOM_VICTIM         25      /* mm is the oom victim */
 #define MMF_OOM_REAP_QUEUED    26      /* mm was queued for oom_reaper */
 #define MMF_DISABLE_THP_MASK   (1 << MMF_DISABLE_THP)
+#define MMF_MM_MANAGE          27
 
 #define MMF_INIT_MASK          (MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK |\
                                 MMF_DISABLE_THP_MASK)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 2c1eb49..47d56c5 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1208,6 +1208,11 @@ asmlinkage long sys_exchange_pages(pid_t pid, unsigned 
long nr_pages,
                                const void __user * __user *to_pages,
                                int __user *status,
                                int flags);
+asmlinkage long sys_mm_manage(pid_t pid, unsigned long nr_pages,
+                               unsigned long maxnode,
+                               const unsigned long __user *old_nodes,
+                               const unsigned long __user *new_nodes,
+                               int flags);
 
 /*
  * Not a real system call, but a placeholder for syscalls which are
diff --git a/include/uapi/linux/mempolicy.h b/include/uapi/linux/mempolicy.h
index a9d03e5..4722bb7 100644
--- a/include/uapi/linux/mempolicy.h
+++ b/include/uapi/linux/mempolicy.h
@@ -52,6 +52,7 @@ enum {
 #define MPOL_MF_MOVE_DMA (1<<5)        /* Use DMA page copy routine */
 #define MPOL_MF_MOVE_MT  (1<<6)        /* Use multi-threaded page copy routine 
*/
 #define MPOL_MF_MOVE_CONCUR  (1<<7)    /* Move pages in a batch */
+#define MPOL_MF_EXCHANGE       (1<<8)  /* Exchange pages */
 
 #define MPOL_MF_VALID  (MPOL_MF_STRICT   |     \
                         MPOL_MF_MOVE     |     \
diff --git a/mm/Makefile b/mm/Makefile
index 2f1f1ad..5302d79 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -47,6 +47,7 @@ obj-y += memblock.o
 obj-y += copy_page.o
 obj-y += exchange.o
 obj-y += exchange_page.o
+obj-y += memory_manage.o
 
 ifdef CONFIG_MMU
        obj-$(CONFIG_ADVISE_SYSCALLS)   += madvise.o
diff --git a/mm/internal.h b/mm/internal.h
index cf63bf6..94feb14 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -574,5 +574,7 @@ bool buffer_migrate_lock_buffers(struct buffer_head *head,
 int writeout(struct address_space *mapping, struct page *page);
 int expected_page_refs(struct address_space *mapping, struct page *page);
 
+int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
+                    unsigned long maxnode);
 
 #endif /* __MM_INTERNAL_H */
diff --git a/mm/memory_manage.c b/mm/memory_manage.c
new file mode 100644
index 0000000..b8f3654
--- /dev/null
+++ b/mm/memory_manage.c
@@ -0,0 +1,109 @@
+/*
+ * A syscall used to move pages between two nodes.
+ */
+
+#include <linux/sched/mm.h>
+#include <linux/cpuset.h>
+#include <linux/mempolicy.h>
+#include <linux/nodemask.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+
+#include "internal.h"
+
+
+SYSCALL_DEFINE6(mm_manage, pid_t, pid, unsigned long, nr_pages,
+               unsigned long, maxnode,
+               const unsigned long __user *, slow_nodes,
+               const unsigned long __user *, fast_nodes,
+               int, flags)
+{
+       const struct cred *cred = current_cred(), *tcred;
+       struct task_struct *task;
+       struct mm_struct *mm = NULL;
+       int err;
+       nodemask_t task_nodes;
+       nodemask_t *slow;
+       nodemask_t *fast;
+       NODEMASK_SCRATCH(scratch);
+
+       if (!scratch)
+               return -ENOMEM;
+
+       slow = &scratch->mask1;
+       fast = &scratch->mask2;
+
+       err = get_nodes(slow, slow_nodes, maxnode);
+       if (err)
+               goto out;
+
+       err = get_nodes(fast, fast_nodes, maxnode);
+       if (err)
+               goto out;
+
+       /* Check flags */
+       if (flags & ~(MPOL_MF_MOVE_MT|
+                                 MPOL_MF_MOVE_DMA|
+                                 MPOL_MF_MOVE_CONCUR|
+                                 MPOL_MF_EXCHANGE))
+               return -EINVAL;
+
+       /* Find the mm_struct */
+       rcu_read_lock();
+       task = pid ? find_task_by_vpid(pid) : current;
+       if (!task) {
+               rcu_read_unlock();
+               err = -ESRCH;
+               goto out;
+       }
+       get_task_struct(task);
+
+       err = -EINVAL;
+       /*
+        * Check if this process has the right to modify the specified
+        * process. The right exists if the process has administrative
+        * capabilities, superuser privileges or the same
+        * userid as the target process.
+        */
+       tcred = __task_cred(task);
+       if (!uid_eq(cred->euid, tcred->suid) && !uid_eq(cred->euid, tcred->uid) 
&&
+           !uid_eq(cred->uid,  tcred->suid) && !uid_eq(cred->uid,  tcred->uid) 
&&
+           !capable(CAP_SYS_NICE)) {
+               rcu_read_unlock();
+               err = -EPERM;
+               goto out_put;
+       }
+       rcu_read_unlock();
+
+       err = security_task_movememory(task);
+       if (err)
+               goto out_put;
+
+       task_nodes = cpuset_mems_allowed(task);
+       mm = get_task_mm(task);
+       put_task_struct(task);
+
+       if (!mm) {
+               err = -EINVAL;
+               goto out;
+       }
+       if (test_bit(MMF_MM_MANAGE, &mm->flags)) {
+               mmput(mm);
+               goto out;
+       } else {
+               set_bit(MMF_MM_MANAGE, &mm->flags);
+       }
+
+
+       clear_bit(MMF_MM_MANAGE, &mm->flags);
+       mmput(mm);
+out:
+       NODEMASK_SCRATCH_FREE(scratch);
+
+       return err;
+
+out_put:
+       put_task_struct(task);
+       goto out;
+
+}
\ No newline at end of file
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 0e30049..168d17f8 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1249,7 +1249,7 @@ static long do_mbind(unsigned long start, unsigned long 
len,
  */
 
 /* Copy a node mask from user space. */
-static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
+int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
                     unsigned long maxnode)
 {
        unsigned long k;
-- 
2.7.4

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