[RFC PATCH 04/31] mm: add mem_defrag functionality.

From: Zi Yan
Date: Fri Feb 15 2019 - 17:04:04 EST

Create contiguous physical memory regions by migrating/exchanging pages.

1. It scans all VMAs in one process and determines an anchor pair
(VPN, PFN) for each VMA.
2. Then, it migrates/exchanges pages in each VMA to make
them aligned with the anchor pair.

At the end of day, a physically contiguous region should be created for
each VMA in the physical address range [PFN, PFN + VMA size).

Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
---
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
fs/exec.c | 4 +
include/linux/mem_defrag.h | 60 +
include/linux/mm.h | 12 +
include/linux/mm_types.h | 4 +
include/linux/sched/coredump.h | 3 +
include/linux/syscalls.h | 3 +
include/linux/vm_event_item.h | 23 +
include/uapi/asm-generic/mman-common.h | 3 +
kernel/fork.c | 9 +
kernel/sysctl.c | 79 +-
mm/Makefile | 1 +
mm/compaction.c | 17 +-
mm/huge_memory.c | 4 +
mm/internal.h | 28 +
mm/khugepaged.c | 1 +
mm/madvise.c | 15 +
mm/mem_defrag.c | 1782 ++++++++++++++++++++++++
mm/memory.c | 7 +
mm/mmap.c | 29 +
mm/page_alloc.c | 4 +-
mm/vmstat.c | 21 +
22 files changed, 2096 insertions(+), 14 deletions(-)
create mode 100644 include/linux/mem_defrag.h
create mode 100644 mm/mem_defrag.c

diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index f0b1709a5ffb..374c11e3cf80 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -343,6 +343,7 @@
332 common statx __x64_sys_statx
333 common io_pgetevents __x64_sys_io_pgetevents
334 common rseq __x64_sys_rseq
+335 common scan_process_memory __x64_sys_scan_process_memory

#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/fs/exec.c b/fs/exec.c
index fb72d36f7823..b71b9d305d7d 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1010,7 +1010,11 @@ static int exec_mmap(struct mm_struct *mm)
{
struct task_struct *tsk;
struct mm_struct *old_mm, *active_mm;
+ int move_mem_defrag = current->mm ?
+ test_bit(MMF_VM_MEM_DEFRAG_ALL, &current->mm->flags):0;

+ if (move_mem_defrag && mm)
+ set_bit(MMF_VM_MEM_DEFRAG_ALL, &mm->flags);
/* Notify parent that we're no longer interested in the old VM */
tsk = current;
old_mm = current->mm;
diff --git a/include/linux/mem_defrag.h b/include/linux/mem_defrag.h
new file mode 100644
index 000000000000..43954a316752
--- /dev/null
+++ b/include/linux/mem_defrag.h
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * mem_defrag.h Memory defragmentation function.
+ *
+ * Copyright (C) 2019 Zi Yan <ziy@xxxxxxxxxx>
+ *
+ *
+ */
+#ifndef _LINUX_KMEM_DEFRAGD_H
+#define _LINUX_KMEM_DEFRAGD_H
+
+#include <linux/sched/coredump.h> /* MMF_VM_MEM_DEFRAG */
+
+#define MEM_DEFRAG_SCAN 0
+#define MEM_DEFRAG_MARK_SCAN_ALL 1
+#define MEM_DEFRAG_CLEAR_SCAN_ALL 2
+#define MEM_DEFRAG_DEFRAG 3
+#define MEM_DEFRAG_CONTIG_SCAN 5
+
+enum mem_defrag_action {
+ MEM_DEFRAG_FULL_STATS = 0,
+ MEM_DEFRAG_DO_DEFRAG,
+ MEM_DEFRAG_CONTIG_STATS,
+};
+
+extern int kmem_defragd_always;
+
+extern int __kmem_defragd_enter(struct mm_struct *mm);
+extern void __kmem_defragd_exit(struct mm_struct *mm);
+extern int memdefrag_madvise(struct vm_area_struct *vma,
+ unsigned long *vm_flags, int advice);
+
+static inline int kmem_defragd_fork(struct mm_struct *mm,
+ struct mm_struct *oldmm)
+{
+ if (test_bit(MMF_VM_MEM_DEFRAG, &oldmm->flags))
+ return __kmem_defragd_enter(mm);
+ return 0;
+}
+
+static inline void kmem_defragd_exit(struct mm_struct *mm)
+{
+ if (test_bit(MMF_VM_MEM_DEFRAG, &mm->flags))
+ __kmem_defragd_exit(mm);
+}
+
+static inline int kmem_defragd_enter(struct vm_area_struct *vma,
+ unsigned long vm_flags)
+{
+ if (!test_bit(MMF_VM_MEM_DEFRAG, &vma->vm_mm->flags))
+ if (((kmem_defragd_always ||
+ ((vm_flags & VM_MEMDEFRAG))) &&
+ !(vm_flags & VM_NOMEMDEFRAG)) ||
+ test_bit(MMF_VM_MEM_DEFRAG_ALL, &vma->vm_mm->flags))
+ if (__kmem_defragd_enter(vma->vm_mm))
+ return -ENOMEM;
+ return 0;
+}
+
+#endif /* _LINUX_KMEM_DEFRAGD_H */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 80bb6408fe73..5bcc1b03372a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -251,13 +251,20 @@ extern unsigned int kobjsize(const void *objp);
#define VM_HIGH_ARCH_BIT_2 34 /* bit only usable on 64-bit architectures */
#define VM_HIGH_ARCH_BIT_3 35 /* bit only usable on 64-bit architectures */
#define VM_HIGH_ARCH_BIT_4 36 /* bit only usable on 64-bit architectures */
+#define VM_HIGH_ARCH_BIT_5 37 /* bit only usable on 64-bit architectures */
+#define VM_HIGH_ARCH_BIT_6 38 /* bit only usable on 64-bit architectures */
#define VM_HIGH_ARCH_0 BIT(VM_HIGH_ARCH_BIT_0)
#define VM_HIGH_ARCH_1 BIT(VM_HIGH_ARCH_BIT_1)
#define VM_HIGH_ARCH_2 BIT(VM_HIGH_ARCH_BIT_2)
#define VM_HIGH_ARCH_3 BIT(VM_HIGH_ARCH_BIT_3)
#define VM_HIGH_ARCH_4 BIT(VM_HIGH_ARCH_BIT_4)
+#define VM_HIGH_ARCH_5 BIT(VM_HIGH_ARCH_BIT_5)
+#define VM_HIGH_ARCH_6 BIT(VM_HIGH_ARCH_BIT_6)
#endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */

+#define VM_MEMDEFRAG VM_HIGH_ARCH_5 /* memory defrag */
+#define VM_NOMEMDEFRAG VM_HIGH_ARCH_6 /* no memory defrag */
+
#ifdef CONFIG_ARCH_HAS_PKEYS
# define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0
# define VM_PKEY_BIT0 VM_HIGH_ARCH_0 /* A protection key is a 4-bit value */
@@ -487,6 +494,9 @@ static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm)
vma->vm_mm = mm;
vma->vm_ops = &dummy_vm_ops;
INIT_LIST_HEAD(&vma->anon_vma_chain);
+ vma->anchor_page_rb = RB_ROOT_CACHED;
+ vma->vma_create_jiffies = jiffies;
+ vma->vma_defrag_jiffies = 0;
}

static inline void vma_set_anonymous(struct vm_area_struct *vma)
@@ -2837,6 +2847,8 @@ static inline bool debug_guardpage_enabled(void) { return false; }
static inline bool page_is_guard(struct page *page) { return false; }
#endif /* CONFIG_DEBUG_PAGEALLOC */

+void free_anchor_pages(struct vm_area_struct *vma);
+
#if MAX_NUMNODES > 1
void __init setup_nr_node_ids(void);
#else
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 2c471a2c43fa..32549b255d25 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -328,6 +328,10 @@ struct vm_area_struct {
struct mempolicy *vm_policy; /* NUMA policy for the VMA */
#endif
struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
+ struct rb_root_cached anchor_page_rb;
+ unsigned long vma_create_jiffies; /* life time of the vma */
+ unsigned long vma_modify_jiffies; /* being modified time of the vma */
+ unsigned long vma_defrag_jiffies; /* being defragged time of the vma */
} __randomize_layout;

struct core_thread {
diff --git a/include/linux/sched/coredump.h b/include/linux/sched/coredump.h
index ecdc6542070f..52ad71db6687 100644
--- a/include/linux/sched/coredump.h
+++ b/include/linux/sched/coredump.h
@@ -76,5 +76,8 @@ static inline int get_dumpable(struct mm_struct *mm)

#define MMF_INIT_MASK (MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK |\
MMF_DISABLE_THP_MASK)
+#define MMF_VM_MEM_DEFRAG 26 /* set mm is added to do mem defrag */
+#define MMF_VM_MEM_DEFRAG_ALL 27 /* all vmas in the mm will be mem defrag */
+

#endif /* _LINUX_SCHED_COREDUMP_H */
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 257cccba3062..caa6f043b29a 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -926,6 +926,8 @@ asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags,
unsigned mask, struct statx __user *buffer);
asmlinkage long sys_rseq(struct rseq __user *rseq, uint32_t rseq_len,
int flags, uint32_t sig);
+asmlinkage long sys_scan_process_memory(pid_t pid, char __user *out_buf,
+ int buf_len, int action);

/*
* Architecture-specific system calls
@@ -1315,4 +1317,5 @@ static inline unsigned int ksys_personality(unsigned int personality)
return old;
}

+
#endif
diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 47a3441cf4c4..6b32c8243616 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -109,6 +109,29 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
#ifdef CONFIG_SWAP
SWAP_RA,
SWAP_RA_HIT,
+#endif
+ /* MEM_DEFRAG STATS */
+ MEM_DEFRAG_DEFRAG_NUM,
+ MEM_DEFRAG_SCAN_NUM,
+ MEM_DEFRAG_DST_FREE_PAGES,
+ MEM_DEFRAG_DST_ANON_PAGES,
+ MEM_DEFRAG_DST_FILE_PAGES,
+ MEM_DEFRAG_DST_NONLRU_PAGES,
+ MEM_DEFRAG_DST_FREE_PAGES_FAILED,
+ MEM_DEFRAG_DST_FREE_PAGES_OVERFLOW_FAILED,
+ MEM_DEFRAG_DST_ANON_PAGES_FAILED,
+ MEM_DEFRAG_DST_FILE_PAGES_FAILED,
+ MEM_DEFRAG_DST_NONLRU_PAGES_FAILED,
+ MEM_DEFRAG_SRC_ANON_PAGES_FAILED,
+ MEM_DEFRAG_SRC_COMP_PAGES_FAILED,
+ MEM_DEFRAG_DST_SPLIT_HUGEPAGES,
+#ifdef CONFIG_COMPACTION
+ /* memory compaction */
+ COMPACT_MIGRATE_PAGES,
+#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ /* thp collapse */
+ THP_COLLAPSE_MIGRATE_PAGES,
#endif
NR_VM_EVENT_ITEMS
};
diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h
index e7ee32861d51..d1ec94a1970d 100644
--- a/include/uapi/asm-generic/mman-common.h
+++ b/include/uapi/asm-generic/mman-common.h
@@ -66,6 +66,9 @@
#define MADV_WIPEONFORK 18 /* Zero memory on fork, child only */
#define MADV_KEEPONFORK 19 /* Undo MADV_WIPEONFORK */

+#define MADV_MEMDEFRAG 20 /* Worth backing with hugepages */
+#define MADV_NOMEMDEFRAG 21 /* Not worth backing with hugepages */
+
/* compatibility flags */
#define MAP_FILE 0

diff --git a/kernel/fork.c b/kernel/fork.c
index b69248e6f0e0..dcefa978c232 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -92,6 +92,7 @@
#include <linux/livepatch.h>
#include <linux/thread_info.h>
#include <linux/stackleak.h>
+#include <linux/mem_defrag.h>

#include <asm/pgtable.h>
#include <asm/pgalloc.h>
@@ -343,12 +344,16 @@ struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig)
if (new) {
*new = *orig;
INIT_LIST_HEAD(&new->anon_vma_chain);
+ new->anchor_page_rb = RB_ROOT_CACHED;
+ new->vma_create_jiffies = jiffies;
+ new->vma_defrag_jiffies = 0;
}
return new;
}

void vm_area_free(struct vm_area_struct *vma)
{
+ free_anchor_pages(vma);
kmem_cache_free(vm_area_cachep, vma);
}

@@ -496,6 +501,9 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
if (retval)
goto out;
retval = khugepaged_fork(mm, oldmm);
+ if (retval)
+ goto out;
+ retval = kmem_defragd_fork(mm, oldmm);
if (retval)
goto out;

@@ -1044,6 +1052,7 @@ static inline void __mmput(struct mm_struct *mm)
exit_aio(mm);
ksm_exit(mm);
khugepaged_exit(mm); /* must run before exit_mmap */
+ kmem_defragd_exit(mm);
exit_mmap(mm);
mm_put_huge_zero_page(mm);
set_mm_exe_file(mm, NULL);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index ba4d9e85feb8..6bf0be1af7e0 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -115,6 +115,13 @@ extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;
extern int sysctl_nr_trim_pages;
#endif

+extern int kmem_defragd_always;
+extern int vma_scan_percentile;
+extern int vma_scan_threshold_type;
+extern int vma_no_repeat_defrag;
+extern int num_breakout_chunks;
+extern int defrag_size_threshold;
+
/* Constants used for minimum and maximum */
#ifdef CONFIG_LOCKUP_DETECTOR
static int sixty = 60;
@@ -1303,7 +1310,7 @@ static struct ctl_table vm_table[] = {
.proc_handler = overcommit_kbytes_handler,
},
{
- .procname = "page-cluster",
+ .procname = "page-cluster",
.data = &page_cluster,
.maxlen = sizeof(int),
.mode = 0644,
@@ -1691,6 +1698,58 @@ static struct ctl_table vm_table[] = {
.extra2 = (void *)&mmap_rnd_compat_bits_max,
},
#endif
+ {
+ .procname = "kmem_defragd_always",
+ .data = &kmem_defragd_always,
+ .maxlen = sizeof(kmem_defragd_always),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
+ {
+ .procname = "vma_scan_percentile",
+ .data = &vma_scan_percentile,
+ .maxlen = sizeof(vma_scan_percentile),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &one_hundred,
+ },
+ {
+ .procname = "vma_scan_threshold_type",
+ .data = &vma_scan_threshold_type,
+ .maxlen = sizeof(vma_scan_threshold_type),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
+ {
+ .procname = "vma_no_repeat_defrag",
+ .data = &vma_no_repeat_defrag,
+ .maxlen = sizeof(vma_no_repeat_defrag),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
+ {
+ .procname = "num_breakout_chunks",
+ .data = &num_breakout_chunks,
+ .maxlen = sizeof(num_breakout_chunks),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ },
+ {
+ .procname = "defrag_size_threshold",
+ .data = &defrag_size_threshold,
+ .maxlen = sizeof(defrag_size_threshold),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ },
{ }
};

@@ -1807,7 +1866,7 @@ static struct ctl_table fs_table[] = {
.mode = 0555,
.child = inotify_table,
},
-#endif
+#endif
#ifdef CONFIG_EPOLL
{
.procname = "epoll",
@@ -2252,12 +2311,12 @@ static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
int *i, vleft, first = 1, err = 0;
size_t left;
char *kbuf = NULL, *p;
-
+
if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
*lenp = 0;
return 0;
}
-
+
i = (int *) tbl_data;
vleft = table->maxlen / sizeof(*i);
left = *lenp;
@@ -2483,7 +2542,7 @@ static int do_proc_douintvec(struct ctl_table *table, int write,
* @ppos: file position
*
* Reads/writes up to table->maxlen/sizeof(unsigned int) integer
- * values from/to the user buffer, treated as an ASCII string.
+ * values from/to the user buffer, treated as an ASCII string.
*
* Returns 0 on success.
*/
@@ -2974,7 +3033,7 @@ static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
* @ppos: file position
*
* Reads/writes up to table->maxlen/sizeof(unsigned int) integer
- * values from/to the user buffer, treated as an ASCII string.
+ * values from/to the user buffer, treated as an ASCII string.
* The values read are assumed to be in seconds, and are converted into
* jiffies.
*
@@ -2996,8 +3055,8 @@ int proc_dointvec_jiffies(struct ctl_table *table, int write,
* @ppos: pointer to the file position
*
* Reads/writes up to table->maxlen/sizeof(unsigned int) integer
- * values from/to the user buffer, treated as an ASCII string.
- * The values read are assumed to be in 1/USER_HZ seconds, and
+ * values from/to the user buffer, treated as an ASCII string.
+ * The values read are assumed to be in 1/USER_HZ seconds, and
* are converted into jiffies.
*
* Returns 0 on success.
@@ -3019,8 +3078,8 @@ int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
* @ppos: the current position in the file
*
* Reads/writes up to table->maxlen/sizeof(unsigned int) integer
- * values from/to the user buffer, treated as an ASCII string.
- * The values read are assumed to be in 1/1000 seconds, and
+ * values from/to the user buffer, treated as an ASCII string.
+ * The values read are assumed to be in 1/1000 seconds, and
* are converted into jiffies.
*
* Returns 0 on success.
diff --git a/mm/Makefile b/mm/Makefile
index 1574ea5743e4..925f21c717db 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -44,6 +44,7 @@ obj-y := filemap.o mempool.o oom_kill.o fadvise.o \
obj-y += init-mm.o
obj-y += memblock.o
obj-y += exchange.o
+obj-y += mem_defrag.o

ifdef CONFIG_MMU
obj-$(CONFIG_ADVISE_SYSCALLS) += madvise.o
diff --git a/mm/compaction.c b/mm/compaction.c
index ef29490b0f46..54c4bfdbdbc3 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -50,7 +50,7 @@ static inline void count_compact_events(enum vm_event_item item, long delta)
#define pageblock_start_pfn(pfn) block_start_pfn(pfn, pageblock_order)
#define pageblock_end_pfn(pfn) block_end_pfn(pfn, pageblock_order)

-static unsigned long release_freepages(struct list_head *freelist)
+unsigned long release_freepages(struct list_head *freelist)
{
struct page *page, *next;
unsigned long high_pfn = 0;
@@ -58,7 +58,10 @@ static unsigned long release_freepages(struct list_head *freelist)
list_for_each_entry_safe(page, next, freelist, lru) {
unsigned long pfn = page_to_pfn(page);
list_del(&page->lru);
- __free_page(page);
+ if (PageCompound(page))
+ __free_pages(page, compound_order(page));
+ else
+ __free_page(page);
if (pfn > high_pfn)
high_pfn = pfn;
}
@@ -1593,6 +1596,8 @@ static enum compact_result compact_zone(struct zone *zone, struct compact_contro

while ((ret = compact_finished(zone, cc)) == COMPACT_CONTINUE) {
int err;
+ int num_migrated_pages = 0;
+ struct page *iter;

switch (isolate_migratepages(zone, cc)) {
case ISOLATE_ABORT:
@@ -1611,6 +1616,9 @@ static enum compact_result compact_zone(struct zone *zone, struct compact_contro
;
}

+ list_for_each_entry(iter, &cc->migratepages, lru)
+ num_migrated_pages++;
+
err = migrate_pages(&cc->migratepages, compaction_alloc,
compaction_free, (unsigned long)cc, cc->mode,
MR_COMPACTION);
@@ -1618,6 +1626,11 @@ static enum compact_result compact_zone(struct zone *zone, struct compact_contro
trace_mm_compaction_migratepages(cc->nr_migratepages, err,
&cc->migratepages);

+ list_for_each_entry(iter, &cc->migratepages, lru)
+ num_migrated_pages--;
+
+ count_vm_events(COMPACT_MIGRATE_PAGES, num_migrated_pages);
+
/* All pages were either migrated or will be released */
cc->nr_migratepages = 0;
if (err) {
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index faf357eaf0ce..ffcae07a87d3 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -33,6 +33,7 @@
#include <linux/page_idle.h>
#include <linux/shmem_fs.h>
#include <linux/oom.h>
+#include <linux/mem_defrag.h>

#include <asm/tlb.h>
#include <asm/pgalloc.h>
@@ -695,6 +696,9 @@ vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf)
return VM_FAULT_OOM;
if (unlikely(khugepaged_enter(vma, vma->vm_flags)))
return VM_FAULT_OOM;
+ /* Make it defrag */
+ if (unlikely(kmem_defragd_enter(vma, vma->vm_flags)))
+ return VM_FAULT_OOM;
if (!(vmf->flags & FAULT_FLAG_WRITE) &&
!mm_forbids_zeropage(vma->vm_mm) &&
transparent_hugepage_use_zero_page()) {
diff --git a/mm/internal.h b/mm/internal.h
index 77e205c423ce..4fe8d1a4d7bb 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -15,6 +15,7 @@
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/tracepoint-defs.h>
+#include <linux/interval_tree.h>

/*
* The set of flags that only affect watermark checking and reclaim
@@ -549,4 +550,31 @@ bool buffer_migrate_lock_buffers(struct buffer_head *head,
int writeout(struct address_space *mapping, struct page *page);
extern int exchange_two_pages(struct page *page1, struct page *page2);

+struct anchor_page_info {
+ struct list_head list;
+ struct page *anchor_page;
+ unsigned long vaddr;
+ unsigned long start;
+ unsigned long end;
+};
+
+struct anchor_page_node {
+ struct interval_tree_node node;
+ unsigned long anchor_pfn; /* struct page can be calculated from pfn_to_page() */
+ unsigned long anchor_vpn;
+};
+
+unsigned long release_freepages(struct list_head *freelist);
+
+void free_anchor_pages(struct vm_area_struct *vma);
+
+extern int exchange_two_pages(struct page *page1, struct page *page2);
+
+void expand(struct zone *zone, struct page *page,
+ int low, int high, struct free_area *area,
+ int migratetype);
+
+void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
+ unsigned int alloc_flags);
+
#endif /* __MM_INTERNAL_H */
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 4f017339ddb2..aedaa9f75806 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -660,6 +660,7 @@ static void __collapse_huge_page_copy(pte_t *pte, struct page *page,
} else {
src_page = pte_page(pteval);
copy_user_highpage(page, src_page, address, vma);
+ count_vm_event(THP_COLLAPSE_MIGRATE_PAGES);
VM_BUG_ON_PAGE(page_mapcount(src_page) != 1, src_page);
release_pte_page(src_page);
/*
diff --git a/mm/madvise.c b/mm/madvise.c
index 21a7881a2db4..9cef96d633e8 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -24,6 +24,7 @@
#include <linux/swapops.h>
#include <linux/shmem_fs.h>
#include <linux/mmu_notifier.h>
+#include <linux/mem_defrag.h>

#include <asm/tlb.h>

@@ -616,6 +617,13 @@ static long madvise_remove(struct vm_area_struct *vma,
return error;
}

+static long madvise_memdefrag(struct vm_area_struct *vma,
+ struct vm_area_struct **prev,
+ unsigned long start, unsigned long end, int behavior)
+{
+ *prev = vma;
+ return memdefrag_madvise(vma, &vma->vm_flags, behavior);
+}
#ifdef CONFIG_MEMORY_FAILURE
/*
* Error injection support for memory error handling.
@@ -697,6 +705,9 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
case MADV_FREE:
case MADV_DONTNEED:
return madvise_dontneed_free(vma, prev, start, end, behavior);
+ case MADV_MEMDEFRAG:
+ case MADV_NOMEMDEFRAG:
+ return madvise_memdefrag(vma, prev, start, end, behavior);
default:
return madvise_behavior(vma, prev, start, end, behavior);
}
@@ -731,6 +742,8 @@ madvise_behavior_valid(int behavior)
case MADV_SOFT_OFFLINE:
case MADV_HWPOISON:
#endif
+ case MADV_MEMDEFRAG:
+ case MADV_NOMEMDEFRAG:
return true;

default:
@@ -785,6 +798,8 @@ madvise_behavior_valid(int behavior)
* MADV_DONTDUMP - the application wants to prevent pages in the given range
* from being included in its core dump.
* MADV_DODUMP - cancel MADV_DONTDUMP: no longer exclude from core dump.
+ * MADV_MEMDEFRAG - allow mem defrag running on this region.
+ * MADV_NOMEMDEFRAG - no mem defrag here.
*
* return values:
* zero - success
diff --git a/mm/mem_defrag.c b/mm/mem_defrag.c
new file mode 100644
index 000000000000..414909e1c19c
--- /dev/null
+++ b/mm/mem_defrag.c
@@ -0,0 +1,1782 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Memory defragmentation.
+ *
+ * Copyright (C) 2019 Zi Yan <ziy@xxxxxxxxxx>
+ *
+ * Two lists:
+ * 1) a mm list, representing virtual address spaces
+ * 2) a anon_vma list, representing the physical address space.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/mm.h>
+#include <linux/sched/mm.h>
+#include <linux/mm_inline.h>
+#include <linux/rmap.h>
+#include <linux/swap.h>
+#include <linux/hashtable.h>
+#include <linux/mem_defrag.h>
+#include <linux/shmem_fs.h>
+#include <linux/syscalls.h>
+#include <linux/security.h>
+#include <linux/vmalloc.h>
+#include <linux/mman.h>
+#include <linux/vmstat.h>
+#include <linux/migrate.h>
+#include <linux/page-isolation.h>
+#include <linux/sort.h>
+
+#include <asm/tlb.h>
+#include <asm/pgalloc.h>
+#include "internal.h"
+
+
+struct contig_stats {
+ int err;
+ unsigned long contig_pages;
+ unsigned long first_vaddr_in_chunk;
+ unsigned long first_paddr_in_chunk;
+};
+
+struct defrag_result_stats {
+ unsigned long aligned;
+ unsigned long migrated;
+ unsigned long src_pte_thp_failed;
+ unsigned long src_thp_dst_not_failed;
+ unsigned long src_not_present;
+ unsigned long dst_out_of_bound_failed;
+ unsigned long dst_pte_thp_failed;
+ unsigned long dst_thp_src_not_failed;
+ unsigned long dst_isolate_free_failed;
+ unsigned long dst_migrate_free_failed;
+ unsigned long dst_anon_failed;
+ unsigned long dst_file_failed;
+ unsigned long dst_non_lru_failed;
+ unsigned long dst_non_moveable_failed;
+ unsigned long not_defrag_vpn;
+};
+
+enum {
+ VMA_THRESHOLD_TYPE_TIME = 0,
+ VMA_THRESHOLD_TYPE_SIZE,
+};
+
+int num_breakout_chunks;
+int vma_scan_percentile = 100;
+int vma_scan_threshold_type = VMA_THRESHOLD_TYPE_TIME;
+int vma_no_repeat_defrag;
+int kmem_defragd_always;
+int defrag_size_threshold = 5;
+static DEFINE_SPINLOCK(kmem_defragd_mm_lock);
+
+#define MM_SLOTS_HASH_BITS 10
+static __read_mostly DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS);
+
+static struct kmem_cache *mm_slot_cache __read_mostly;
+
+struct defrag_scan_control {
+ struct mm_struct *mm;
+ unsigned long scan_address;
+ char __user *out_buf;
+ int buf_len;
+ int used_len;
+ enum mem_defrag_action action;
+ bool scan_in_vma;
+ unsigned long vma_scan_threshold;
+};
+
+/**
+ * struct mm_slot - hash lookup from mm to mm_slot
+ * @hash: hash collision list
+ * @mm_node: kmem_defragd scan list headed in kmem_defragd_scan.mm_head
+ * @mm: the mm that this information is valid for
+ */
+struct mm_slot {
+ struct hlist_node hash;
+ struct list_head mm_node;
+ struct mm_struct *mm;
+};
+
+/**
+ * struct kmem_defragd_scan - cursor for scanning
+ * @mm_head: the head of the mm list to scan
+ * @mm_slot: the current mm_slot we are scanning
+ * @address: the next address inside that to be scanned
+ *
+ * There is only the one kmem_defragd_scan instance of this cursor structure.
+ */
+struct kmem_defragd_scan {
+ struct list_head mm_head;
+ struct mm_slot *mm_slot;
+ unsigned long address;
+};
+
+static struct kmem_defragd_scan kmem_defragd_scan = {
+ .mm_head = LIST_HEAD_INIT(kmem_defragd_scan.mm_head),
+};
+
+
+static inline struct mm_slot *alloc_mm_slot(void)
+{
+ if (!mm_slot_cache) /* initialization failed */
+ return NULL;
+ return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL);
+}
+
+static inline void free_mm_slot(struct mm_slot *mm_slot)
+{
+ kmem_cache_free(mm_slot_cache, mm_slot);
+}
+
+static struct mm_slot *get_mm_slot(struct mm_struct *mm)
+{
+ struct mm_slot *mm_slot;
+
+ hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm)
+ if (mm == mm_slot->mm)
+ return mm_slot;
+
+ return NULL;
+}
+
+static void insert_to_mm_slots_hash(struct mm_struct *mm,
+ struct mm_slot *mm_slot)
+{
+ mm_slot->mm = mm;
+ hash_add(mm_slots_hash, &mm_slot->hash, (long)mm);
+}
+
+static inline int kmem_defragd_test_exit(struct mm_struct *mm)
+{
+ return atomic_read(&mm->mm_users) == 0;
+}
+
+int __kmem_defragd_enter(struct mm_struct *mm)
+{
+ struct mm_slot *mm_slot;
+
+ mm_slot = alloc_mm_slot();
+ if (!mm_slot)
+ return -ENOMEM;
+
+ /* __kmem_defragd_exit() must not run from under us */
+ VM_BUG_ON_MM(kmem_defragd_test_exit(mm), mm);
+ if (unlikely(test_and_set_bit(MMF_VM_MEM_DEFRAG, &mm->flags))) {
+ free_mm_slot(mm_slot);
+ return 0;
+ }
+
+ spin_lock(&kmem_defragd_mm_lock);
+ insert_to_mm_slots_hash(mm, mm_slot);
+ /*
+ * Insert just behind the scanning cursor, to let the area settle
+ * down a little.
+ */
+ list_add_tail(&mm_slot->mm_node, &kmem_defragd_scan.mm_head);
+ spin_unlock(&kmem_defragd_mm_lock);
+
+ atomic_inc(&mm->mm_count);
+
+ return 0;
+}
+
+void __kmem_defragd_exit(struct mm_struct *mm)
+{
+ struct mm_slot *mm_slot;
+ int free = 0;
+
+ spin_lock(&kmem_defragd_mm_lock);
+ mm_slot = get_mm_slot(mm);
+ if (mm_slot && kmem_defragd_scan.mm_slot != mm_slot) {
+ hash_del(&mm_slot->hash);
+ list_del(&mm_slot->mm_node);
+ free = 1;
+ }
+ spin_unlock(&kmem_defragd_mm_lock);
+
+ if (free) {
+ clear_bit(MMF_VM_MEM_DEFRAG, &mm->flags);
+ free_mm_slot(mm_slot);
+ mmdrop(mm);
+ } else if (mm_slot) {
+ /*
+ * This is required to serialize against
+ * kmem_defragd_test_exit() (which is guaranteed to run
+ * under mmap sem read mode). Stop here (after we
+ * return all pagetables will be destroyed) until
+ * kmem_defragd has finished working on the pagetables
+ * under the mmap_sem.
+ */
+ down_write(&mm->mmap_sem);
+ up_write(&mm->mmap_sem);
+ }
+}
+
+static void collect_mm_slot(struct mm_slot *mm_slot)
+{
+ struct mm_struct *mm = mm_slot->mm;
+
+ VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&kmem_defragd_mm_lock));
+
+ if (kmem_defragd_test_exit(mm)) {
+ /* free mm_slot */
+ hash_del(&mm_slot->hash);
+ list_del(&mm_slot->mm_node);
+
+ /*
+ * Not strictly needed because the mm exited already.
+ *
+ * clear_bit(MMF_VM_HUGEPAGE, &mm->flags);
+ */
+
+ /* kmem_defragd_mm_lock actually not necessary for the below */
+ free_mm_slot(mm_slot);
+ mmdrop(mm);
+ }
+}
+
+static bool mem_defrag_vma_check(struct vm_area_struct *vma)
+{
+ if ((!test_bit(MMF_VM_MEM_DEFRAG_ALL, &vma->vm_mm->flags) &&
+ !(vma->vm_flags & VM_MEMDEFRAG) && !kmem_defragd_always) ||
+ (vma->vm_flags & VM_NOMEMDEFRAG))
+ return false;
+ if (shmem_file(vma->vm_file)) {
+ if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE))
+ return false;
+ return IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff,
+ HPAGE_PMD_NR);
+ }
+ if (is_vm_hugetlb_page(vma))
+ return true;
+ if (!vma->anon_vma || vma->vm_ops)
+ return false;
+ if (is_vma_temporary_stack(vma))
+ return false;
+ return true;
+}
+
+static int do_vma_stat(struct mm_struct *mm, struct vm_area_struct *vma,
+ char *kernel_buf, int pos, int *remain_buf_len)
+{
+ int used_len;
+ int init_remain_len = *remain_buf_len;
+
+ if (!*remain_buf_len || !kernel_buf)
+ return -1;
+
+ used_len = scnprintf(kernel_buf + pos, *remain_buf_len, "%p, 0x%lx, 0x%lx, "
+ "0x%lx, -1\n",
+ mm, (unsigned long)vma+vma->vma_create_jiffies,
+ vma->vm_start, vma->vm_end);
+
+ *remain_buf_len -= used_len;
+
+ if (*remain_buf_len == 1) {
+ *remain_buf_len = init_remain_len;
+ kernel_buf[pos] = '\0';
+ return -1;
+ }
+
+ return 0;
+}
+
+static inline int get_contig_page_size(struct page *page)
+{
+ int page_size = PAGE_SIZE;
+
+ if (PageCompound(page)) {
+ struct page *head_page = compound_head(page);
+ int compound_size = PAGE_SIZE<<compound_order(head_page);
+
+ if (head_page != page) {
+ VM_BUG_ON_PAGE(!PageTail(page), page);
+ page_size = compound_size - (page - head_page) * PAGE_SIZE;
+ } else
+ page_size = compound_size;
+ }
+
+ return page_size;
+}
+
+/*
+ * write one page stats to kernel_buf.
+ *
+ * If kernel_buf is not big enough, the page information will not be recorded
+ * at all.
+ *
+ */
+static int do_page_stat(struct mm_struct *mm, struct vm_area_struct *vma,
+ struct page *page, unsigned long vaddr,
+ char *kernel_buf, int pos, int *remain_buf_len,
+ enum mem_defrag_action action,
+ struct contig_stats *contig_stats,
+ bool scan_in_vma)
+{
+ int used_len;
+ struct anon_vma *anon_vma;
+ int init_remain_len = *remain_buf_len;
+ int end_note = -1;
+ unsigned long num_pages = page?(get_contig_page_size(page)/PAGE_SIZE):1;
+
+ if (!*remain_buf_len || !kernel_buf)
+ return -1;
+
+ if (action == MEM_DEFRAG_CONTIG_STATS) {
+ long long contig_pages;
+ unsigned long paddr = page?PFN_PHYS(page_to_pfn(page)):0;
+ bool last_entry = false;
+
+ if (!contig_stats->first_vaddr_in_chunk) {
+ contig_stats->first_vaddr_in_chunk = vaddr;
+ contig_stats->first_paddr_in_chunk = paddr;
+ contig_stats->contig_pages = 0;
+ }
+
+ /* scan_in_vma is set to true if buffer runs out while scanning a
+ * vma. A corner case happens, when buffer runs out, then vma changes,
+ * scan_address is reset to vm_start. Then, vma info is printed twice.
+ */
+ if (vaddr == vma->vm_start && !scan_in_vma) {
+ used_len = scnprintf(kernel_buf + pos, *remain_buf_len,
+ "%p, 0x%lx, 0x%lx, 0x%lx, ",
+ mm, (unsigned long)vma+vma->vma_create_jiffies,
+ vma->vm_start, vma->vm_end);
+
+ *remain_buf_len -= used_len;
+
+ if (*remain_buf_len == 1) {
+ contig_stats->err = 1;
+ goto out_of_buf;
+ }
+ pos += used_len;
+ }
+
+ if (page) {
+ if (contig_stats->first_paddr_in_chunk) {
+ if (((long long)vaddr - contig_stats->first_vaddr_in_chunk) ==
+ ((long long)paddr - contig_stats->first_paddr_in_chunk))
+ contig_stats->contig_pages += num_pages;
+ else {
+ /* output present contig chunk */
+ contig_pages = contig_stats->contig_pages;
+ goto output_contig_info;
+ }
+ } else { /* the previous chunk is not present pages */
+ /* output non-present contig chunk */
+ contig_pages = -(long long)contig_stats->contig_pages;
+ goto output_contig_info;
+ }
+ } else {
+ /* the previous chunk is not present pages */
+ if (!contig_stats->first_paddr_in_chunk) {
+ VM_BUG_ON(contig_stats->first_vaddr_in_chunk +
+ contig_stats->contig_pages * PAGE_SIZE !=
+ vaddr);
+ ++contig_stats->contig_pages;
+ } else {
+ /* output present contig chunk */
+ contig_pages = contig_stats->contig_pages;
+
+ goto output_contig_info;
+ }
+ }
+
+check_last_entry:
+ /* if vaddr is the last page, we need to dump stats as well */
+ if ((vaddr + num_pages * PAGE_SIZE) >= vma->vm_end) {
+ if (contig_stats->first_paddr_in_chunk)
+ contig_pages = contig_stats->contig_pages;
+ else
+ contig_pages = -(long long)contig_stats->contig_pages;
+ last_entry = true;
+ } else
+ return 0;
+output_contig_info:
+ if (last_entry)
+ used_len = scnprintf(kernel_buf + pos, *remain_buf_len,
+ "%lld, -1\n", contig_pages);
+ else
+ used_len = scnprintf(kernel_buf + pos, *remain_buf_len,
+ "%lld, ", contig_pages);
+
+ *remain_buf_len -= used_len;
+ if (*remain_buf_len == 1) {
+ contig_stats->err = 1;
+ goto out_of_buf;
+ } else {
+ pos += used_len;
+ if (last_entry) {
+ /* clear contig_stats */
+ contig_stats->first_vaddr_in_chunk = 0;
+ contig_stats->first_paddr_in_chunk = 0;
+ contig_stats->contig_pages = 0;
+ return 0;
+ } else {
+ /* set new contig_stats */
+ contig_stats->first_vaddr_in_chunk = vaddr;
+ contig_stats->first_paddr_in_chunk = paddr;
+ contig_stats->contig_pages = num_pages;
+ goto check_last_entry;
+ }
+ }
+ return 0;
+ }
+
+ used_len = scnprintf(kernel_buf + pos, *remain_buf_len,
+ "%p, %p, 0x%lx, 0x%lx, 0x%lx, 0x%llx",
+ mm, vma, vma->vm_start, vma->vm_end,
+ vaddr, page ? PFN_PHYS(page_to_pfn(page)) : 0);
+
+ *remain_buf_len -= used_len;
+ if (*remain_buf_len == 1)
+ goto out_of_buf;
+ pos += used_len;
+
+ if (page && PageAnon(page)) {
+ /* check page order */
+ used_len = scnprintf(kernel_buf + pos, *remain_buf_len, ", %d",
+ compound_order(page));
+ *remain_buf_len -= used_len;
+ if (*remain_buf_len == 1)
+ goto out_of_buf;
+ pos += used_len;
+
+ anon_vma = page_anon_vma(page);
+ if (!anon_vma)
+ goto end_of_stat;
+ anon_vma_lock_read(anon_vma);
+
+ do {
+ used_len = scnprintf(kernel_buf + pos, *remain_buf_len, ", %p",
+ anon_vma);
+ *remain_buf_len -= used_len;
+ if (*remain_buf_len == 1) {
+ anon_vma_unlock_read(anon_vma);
+ goto out_of_buf;
+ }
+ pos += used_len;
+
+ anon_vma = anon_vma->parent;
+ } while (anon_vma != anon_vma->parent);
+
+ anon_vma_unlock_read(anon_vma);
+ }
+end_of_stat:
+ /* end of one page stat */
+ used_len = scnprintf(kernel_buf + pos, *remain_buf_len, ", %d\n", end_note);
+ *remain_buf_len -= used_len;
+ if (*remain_buf_len == 1)
+ goto out_of_buf;
+
+ return 0;
+out_of_buf: /* revert incomplete data */
+ *remain_buf_len = init_remain_len;
+ kernel_buf[pos] = '\0';
+ return -1;
+
+}
+
+static int isolate_free_page_no_wmark(struct page *page, unsigned int order)
+{
+ struct zone *zone;
+ int mt;
+
+ VM_BUG_ON(!PageBuddy(page));
+
+ zone = page_zone(page);
+ mt = get_pageblock_migratetype(page);
+
+
+ /* Remove page from free list */
+ list_del(&page->lru);
+ zone->free_area[order].nr_free--;
+ __ClearPageBuddy(page);
+ set_page_private(page, 0);
+
+ /*
+ * Set the pageblock if the isolated page is at least half of a
+ * pageblock
+ */
+ if (order >= pageblock_order - 1) {
+ struct page *endpage = page + (1 << order) - 1;
+
+ for (; page < endpage; page += pageblock_nr_pages) {
+ int mt = get_pageblock_migratetype(page);
+
+ if (!is_migrate_isolate(mt) && !is_migrate_cma(mt)
+ && mt != MIGRATE_HIGHATOMIC)
+ set_pageblock_migratetype(page,
+ MIGRATE_MOVABLE);
+ }
+ }
+
+ return 1UL << order;
+}
+
+struct exchange_alloc_info {
+ struct list_head list;
+ struct page *src_page;
+ struct page *dst_page;
+};
+
+struct exchange_alloc_head {
+ struct list_head exchange_list;
+ struct list_head freelist;
+ struct list_head migratepage_list;
+ unsigned long num_freepages;
+};
+
+static int create_exchange_alloc_info(struct vm_area_struct *vma,
+ unsigned long scan_address, struct page *first_in_use_page,
+ int total_free_pages,
+ struct list_head *freelist,
+ struct list_head *exchange_list,
+ struct list_head *migratepage_list)
+{
+ struct page *in_use_page;
+ struct page *freepage;
+ struct exchange_alloc_info *one_pair;
+ int err;
+ int pagevec_flushed = 0;
+
+ down_read(&vma->vm_mm->mmap_sem);
+ in_use_page = follow_page(vma, scan_address,
+ FOLL_GET|FOLL_MIGRATION | FOLL_REMOTE);
+ up_read(&vma->vm_mm->mmap_sem);
+
+ freepage = list_first_entry_or_null(freelist, struct page, lru);
+
+ if (first_in_use_page != in_use_page ||
+ !freepage ||
+ PageCompound(in_use_page) != PageCompound(freepage) ||
+ compound_order(in_use_page) != compound_order(freepage)) {
+ if (in_use_page)
+ put_page(in_use_page);
+ return -EBUSY;
+ }
+ one_pair = kmalloc(sizeof(struct exchange_alloc_info),
+ GFP_KERNEL | __GFP_ZERO);
+
+ if (!one_pair) {
+ put_page(in_use_page);
+ return -ENOMEM;
+ }
+
+retry_isolate:
+ /* isolate in_use_page */
+ err = isolate_lru_page(in_use_page);
+ if (err) {
+ if (!pagevec_flushed) {
+ migrate_prep();
+ pagevec_flushed = 1;
+ goto retry_isolate;
+ }
+ put_page(in_use_page);
+ in_use_page = NULL;
+ }
+
+ if (in_use_page) {
+ put_page(in_use_page);
+ mod_node_page_state(page_pgdat(in_use_page),
+ NR_ISOLATED_ANON + page_is_file_cache(in_use_page),
+ hpage_nr_pages(in_use_page));
+ list_add_tail(&in_use_page->lru, migratepage_list);
+ }
+ /* fill info */
+ one_pair->src_page = in_use_page;
+ one_pair->dst_page = freepage;
+ INIT_LIST_HEAD(&one_pair->list);
+
+ list_add_tail(&one_pair->list, exchange_list);
+
+ return 0;
+}
+
+static void free_alloc_info(struct list_head *alloc_info_list)
+{
+ struct exchange_alloc_info *item, *item2;
+
+ list_for_each_entry_safe(item, item2, alloc_info_list, list) {
+ list_del(&item->list);
+ kfree(item);
+ }
+}
+
+/*
+ * migrate callback: give a specific free page when it is called to guarantee
+ * contiguity after migration.
+ */
+static struct page *exchange_alloc(struct page *migratepage,
+ unsigned long data)
+{
+ struct exchange_alloc_head *head = (struct exchange_alloc_head *)data;
+ struct page *freepage = NULL;
+ struct exchange_alloc_info *info;
+
+ list_for_each_entry(info, &head->exchange_list, list) {
+ if (migratepage == info->src_page) {
+ freepage = info->dst_page;
+ /* remove it from freelist */
+ list_del(&freepage->lru);
+ if (PageTransHuge(freepage))
+ head->num_freepages -= HPAGE_PMD_NR;
+ else
+ head->num_freepages--;
+ break;
+ }
+ }
+
+ return freepage;
+}
+
+static void exchange_free(struct page *freepage, unsigned long data)
+{
+ struct exchange_alloc_head *head = (struct exchange_alloc_head *)data;
+
+ list_add_tail(&freepage->lru, &head->freelist);
+ if (PageTransHuge(freepage))
+ head->num_freepages += HPAGE_PMD_NR;
+ else
+ head->num_freepages++;
+}
+
+int defrag_address_range(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long start_addr, unsigned long end_addr,
+ struct page *anchor_page, unsigned long page_vaddr,
+ struct defrag_result_stats *defrag_stats)
+{
+ /*unsigned long va_pa_page_offset = (unsigned long)-1;*/
+ unsigned long scan_address;
+ unsigned long page_size = PAGE_SIZE;
+ int failed = 0;
+ int not_present = 0;
+ bool src_thp = false;
+
+ for (scan_address = start_addr; scan_address < end_addr;
+ scan_address += page_size) {
+ struct page *scan_page;
+ unsigned long scan_phys_addr;
+ long long page_dist;
+
+ cond_resched();
+
+ down_read(&vma->vm_mm->mmap_sem);
+ scan_page = follow_page(vma, scan_address, FOLL_MIGRATION | FOLL_REMOTE);
+ up_read(&vma->vm_mm->mmap_sem);
+ scan_phys_addr = PFN_PHYS(scan_page ? page_to_pfn(scan_page) : 0);
+
+ page_size = PAGE_SIZE;
+
+ if (!scan_phys_addr) {
+ not_present++;
+ failed += 1;
+ defrag_stats->src_not_present += 1;
+ continue;
+ }
+
+ page_size = get_contig_page_size(scan_page);
+
+ /* PTE-mapped THP not allowed */
+ if ((scan_page == compound_head(scan_page)) &&
+ PageTransHuge(scan_page) && !PageHuge(scan_page))
+ src_thp = true;
+
+ /* Allow THPs */
+ if (PageCompound(scan_page) && !src_thp) {
+ count_vm_events(MEM_DEFRAG_SRC_COMP_PAGES_FAILED, page_size/PAGE_SIZE);
+ failed += (page_size/PAGE_SIZE);
+ defrag_stats->src_pte_thp_failed += (page_size/PAGE_SIZE);
+
+ defrag_stats->not_defrag_vpn = scan_address + page_size;
+ goto quit_defrag;
+ continue;
+ }
+
+ VM_BUG_ON(!anchor_page);
+
+ page_dist = ((long long)scan_address - page_vaddr) / PAGE_SIZE;
+
+ /* already in the contiguous pos */
+ if (page_dist == (long long)(scan_page - anchor_page)) {
+ defrag_stats->aligned += (page_size/PAGE_SIZE);
+ continue;
+ } else { /* migrate pages according to the anchor pages in the vma. */
+ struct page *dest_page = anchor_page + page_dist;
+ int page_drained = 0;
+ bool dst_thp = false;
+ int scan_page_order = src_thp?compound_order(scan_page):0;
+
+ if (!zone_spans_pfn(page_zone(anchor_page),
+ (page_to_pfn(anchor_page) + page_dist))) {
+ failed += 1;
+ defrag_stats->dst_out_of_bound_failed += 1;
+
+ defrag_stats->not_defrag_vpn = scan_address + page_size;
+ goto quit_defrag;
+ continue;
+ }
+
+retry_defrag:
+ /* migrate */
+ if (PageBuddy(dest_page)) {
+ struct zone *zone = page_zone(dest_page);
+ spinlock_t *zone_lock = &zone->lock;
+ unsigned long zone_lock_flags;
+ unsigned long free_page_order = 0;
+ int err = 0;
+ struct exchange_alloc_head exchange_alloc_head = {0};
+ int migratetype = get_pageblock_migratetype(dest_page);
+
+ INIT_LIST_HEAD(&exchange_alloc_head.exchange_list);
+ INIT_LIST_HEAD(&exchange_alloc_head.freelist);
+ INIT_LIST_HEAD(&exchange_alloc_head.migratepage_list);
+
+ count_vm_events(MEM_DEFRAG_DST_FREE_PAGES, 1<<scan_page_order);
+
+ /* lock page_zone(dest_page)->lock */
+ spin_lock_irqsave(zone_lock, zone_lock_flags);
+
+ if (!PageBuddy(dest_page)) {
+ err = -EINVAL;
+ goto freepage_isolate_fail;
+ }
+
+ free_page_order = page_order(dest_page);
+
+ /* fail early if not enough free pages */
+ if (free_page_order < scan_page_order) {
+ err = -ENOMEM;
+ goto freepage_isolate_fail;
+ }
+
+ /* __isolate_free_page() */
+ err = isolate_free_page_no_wmark(dest_page, free_page_order);
+ if (!err)
+ goto freepage_isolate_fail;
+
+ expand(zone, dest_page, scan_page_order, free_page_order,
+ &(zone->free_area[free_page_order]),
+ migratetype);
+
+ if (!is_migrate_isolate(migratetype))
+ __mod_zone_freepage_state(zone, -(1UL << scan_page_order),
+ migratetype);
+
+ prep_new_page(dest_page, scan_page_order,
+ __GFP_MOVABLE|(scan_page_order?__GFP_COMP:0), 0);
+
+ if (scan_page_order) {
+ VM_BUG_ON(!src_thp);
+ VM_BUG_ON(scan_page_order != HPAGE_PMD_ORDER);
+ prep_transhuge_page(dest_page);
+ }
+
+ list_add(&dest_page->lru, &exchange_alloc_head.freelist);
+
+freepage_isolate_fail:
+ spin_unlock_irqrestore(zone_lock, zone_lock_flags);
+
+ if (err < 0) {
+ failed += (page_size/PAGE_SIZE);
+ defrag_stats->dst_isolate_free_failed += (page_size/PAGE_SIZE);
+
+ defrag_stats->not_defrag_vpn = scan_address + page_size;
+ goto quit_defrag;
+ continue;
+ }
+
+ /* gather in-use pages
+ * create a exchange_alloc_info structure, a list of
+ * tuples, each like:
+ * (in_use_page, free_page)
+ *
+ * so in exchange_alloc, the code needs to traverse the list
+ * and find the tuple from in_use_page. Then return the
+ * corresponding free page.
+ *
+ * This can guarantee the contiguity after migration.
+ */
+
+ err = create_exchange_alloc_info(vma, scan_address, scan_page,
+ 1<<free_page_order,
+ &exchange_alloc_head.freelist,
+ &exchange_alloc_head.exchange_list,
+ &exchange_alloc_head.migratepage_list);
+
+ if (err)
+ pr_debug("create_exchange_alloc_info error: %d\n", err);
+
+ exchange_alloc_head.num_freepages = 1<<scan_page_order;
+
+ /* migrate pags */
+ err = migrate_pages(&exchange_alloc_head.migratepage_list,
+ exchange_alloc, exchange_free,
+ (unsigned long)&exchange_alloc_head,
+ MIGRATE_SYNC, MR_COMPACTION);
+
+ /* putback not migrated in_use_pagelist */
+ putback_movable_pages(&exchange_alloc_head.migratepage_list);
+
+ /* release free pages in freelist */
+ release_freepages(&exchange_alloc_head.freelist);
+
+ /* free allocated exchange info */
+ free_alloc_info(&exchange_alloc_head.exchange_list);
+
+ count_vm_events(MEM_DEFRAG_DST_FREE_PAGES_FAILED,
+ exchange_alloc_head.num_freepages);
+
+ if (exchange_alloc_head.num_freepages) {
+ failed += exchange_alloc_head.num_freepages;
+ defrag_stats->dst_migrate_free_failed +=
+ exchange_alloc_head.num_freepages;
+ }
+ defrag_stats->migrated += ((1UL<<scan_page_order) -
+ exchange_alloc_head.num_freepages);
+
+ } else { /* exchange */
+ int err = -EBUSY;
+
+ /* PTE-mapped THP not allowed */
+ if ((dest_page == compound_head(dest_page)) &&
+ PageTransHuge(dest_page) && !PageHuge(dest_page))
+ dst_thp = true;
+
+ if (PageCompound(dest_page) && !dst_thp) {
+ failed += get_contig_page_size(dest_page);
+ defrag_stats->dst_pte_thp_failed += page_size/PAGE_SIZE;
+
+ defrag_stats->not_defrag_vpn = scan_address + page_size;
+ goto quit_defrag;
+ }
+
+ if (src_thp != dst_thp) {
+ failed += get_contig_page_size(scan_page);
+ if (src_thp && !dst_thp)
+ defrag_stats->src_thp_dst_not_failed +=
+ page_size/PAGE_SIZE;
+ else /* !src_thp && dst_thp */
+ defrag_stats->dst_thp_src_not_failed +=
+ page_size/PAGE_SIZE;
+
+ defrag_stats->not_defrag_vpn = scan_address + page_size;
+ goto quit_defrag;
+ /*continue;*/
+ }
+
+ /* free page on pcplist */
+ if (page_count(dest_page) == 0) {
+ /* not managed pages */
+ if (!dest_page->flags) {
+ failed += 1;
+ defrag_stats->dst_out_of_bound_failed += 1;
+
+ defrag_stats->not_defrag_vpn = scan_address + page_size;
+ goto quit_defrag;
+ }
+ /* spill order-0 pages to buddy allocator from pcplist */
+ if (!page_drained) {
+ drain_all_pages(NULL);
+ page_drained = 1;
+ goto retry_defrag;
+ }
+ }
+
+ if (PageAnon(dest_page)) {
+ count_vm_events(MEM_DEFRAG_DST_ANON_PAGES,
+ 1<<scan_page_order);
+
+ err = exchange_two_pages(scan_page, dest_page);
+ if (err) {
+ count_vm_events(MEM_DEFRAG_DST_ANON_PAGES_FAILED,
+ 1<<scan_page_order);
+ failed += 1<<scan_page_order;
+ defrag_stats->dst_anon_failed += 1<<scan_page_order;
+ }
+ } else if (page_mapping(dest_page)) {
+ count_vm_events(MEM_DEFRAG_DST_FILE_PAGES,
+ 1<<scan_page_order);
+
+ err = exchange_two_pages(scan_page, dest_page);
+ if (err) {
+ count_vm_events(MEM_DEFRAG_DST_FILE_PAGES_FAILED,
+ 1<<scan_page_order);
+ failed += 1<<scan_page_order;
+ defrag_stats->dst_file_failed += 1<<scan_page_order;
+ }
+ } else if (!PageLRU(dest_page) && __PageMovable(dest_page)) {
+ err = -ENODEV;
+ count_vm_events(MEM_DEFRAG_DST_NONLRU_PAGES,
+ 1<<scan_page_order);
+ failed += 1<<scan_page_order;
+ defrag_stats->dst_non_lru_failed += 1<<scan_page_order;
+ count_vm_events(MEM_DEFRAG_DST_NONLRU_PAGES_FAILED,
+ 1<<scan_page_order);
+ } else {
+ err = -ENODEV;
+ failed += 1<<scan_page_order;
+ /* unmovable pages */
+ defrag_stats->dst_non_moveable_failed += 1<<scan_page_order;
+ }
+
+ if (err == -EAGAIN)
+ goto retry_defrag;
+ if (!err)
+ defrag_stats->migrated += 1<<scan_page_order;
+ else {
+
+ defrag_stats->not_defrag_vpn = scan_address + page_size;
+ goto quit_defrag;
+ }
+
+ }
+ }
+ }
+quit_defrag:
+ return failed;
+}
+
+struct anchor_page_node *get_anchor_page_node_from_vma(struct vm_area_struct *vma,
+ unsigned long address)
+{
+ struct interval_tree_node *prev_vma_node;
+
+ prev_vma_node = interval_tree_iter_first(&vma->anchor_page_rb,
+ address, address);
+
+ if (!prev_vma_node)
+ return NULL;
+
+ return container_of(prev_vma_node, struct anchor_page_node, node);
+}
+
+unsigned long get_undefragged_area(struct zone *zone, struct vm_area_struct *vma,
+ unsigned long start_addr, unsigned long end_addr)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ struct vm_area_struct *scan_vma = NULL;
+ unsigned long vma_size = end_addr - start_addr;
+ bool first_vma = true;
+
+ for (scan_vma = mm->mmap; scan_vma; scan_vma = scan_vma->vm_next)
+ if (!RB_EMPTY_ROOT(&scan_vma->anchor_page_rb.rb_root))
+ break;
+ /* no defragged area */
+ if (!scan_vma)
+ return zone->zone_start_pfn;
+
+ scan_vma = mm->mmap;
+ while (scan_vma) {
+ if (!RB_EMPTY_ROOT(&scan_vma->anchor_page_rb.rb_root)) {
+ struct interval_tree_node *node = NULL, *next_node = NULL;
+ struct anchor_page_node *anchor_node, *next_anchor_node = NULL;
+ struct vm_area_struct *next_vma = scan_vma->vm_next;
+ unsigned long end_pfn;
+ /* each vma get one anchor range */
+ node = interval_tree_iter_first(&scan_vma->anchor_page_rb,
+ scan_vma->vm_start, scan_vma->vm_end - 1);
+ if (!node) {
+ scan_vma = scan_vma->vm_next;
+ continue;
+ }
+
+ anchor_node = container_of(node, struct anchor_page_node, node);
+ end_pfn = (anchor_node->anchor_pfn +
+ ((scan_vma->vm_end - scan_vma->vm_start)>>PAGE_SHIFT));
+
+ /* check space before first vma */
+ if (first_vma) {
+ first_vma = false;
+ if (zone->zone_start_pfn + vma_size < anchor_node->anchor_pfn)
+ return zone->zone_start_pfn;
+ /* remove existing anchor if new vma is much larger */
+ if (vma_size > (scan_vma->vm_end - scan_vma->vm_start)*2) {
+ first_vma = true;
+ interval_tree_remove(node, &scan_vma->anchor_page_rb);
+ kfree(anchor_node);
+ scan_vma = scan_vma->vm_next;
+ continue;
+ }
+ }
+
+ /* find next vma with anchor range */
+ for (next_vma = scan_vma->vm_next;
+ next_vma && RB_EMPTY_ROOT(&next_vma->anchor_page_rb.rb_root);
+ next_vma = next_vma->vm_next);
+
+ if (!next_vma)
+ return end_pfn;
+ else {
+ next_node = interval_tree_iter_first(&next_vma->anchor_page_rb,
+ next_vma->vm_start, next_vma->vm_end - 1);
+ VM_BUG_ON(!next_node);
+ next_anchor_node = container_of(next_node,
+ struct anchor_page_node, node);
+ if (end_pfn + vma_size < next_anchor_node->anchor_pfn)
+ return end_pfn;
+ }
+ scan_vma = next_vma;
+ } else
+ scan_vma = scan_vma->vm_next;
+ }
+
+ return zone->zone_start_pfn;
+}
+
+/*
+ * anchor pages decide the va pa offset in each vma
+ *
+ */
+static int find_anchor_pages_in_vma(struct mm_struct *mm,
+ struct vm_area_struct *vma, unsigned long start_addr)
+{
+ struct anchor_page_node *anchor_node;
+ unsigned long end_addr = vma->vm_end - PAGE_SIZE;
+ struct interval_tree_node *existing_anchor = NULL;
+ unsigned long scan_address = start_addr;
+ struct page *present_page = NULL;
+ struct zone *present_zone = NULL;
+ unsigned long alignment_size = PAGE_SIZE;
+
+ /* Out of range query */
+ if (start_addr >= vma->vm_end || start_addr < vma->vm_start)
+ return -1;
+
+ /*
+ * Clean up unrelated anchor infor
+ *
+ * VMA range can change and leave some anchor info out of range,
+ * so clean it here.
+ * It should be cleaned when vma is changed, but the code there
+ * is too complicated.
+ */
+ if (!RB_EMPTY_ROOT(&vma->anchor_page_rb.rb_root) &&
+ !interval_tree_iter_first(&vma->anchor_page_rb,
+ vma->vm_start, vma->vm_end - 1)) {
+ struct interval_tree_node *node = NULL;
+
+ for (node = interval_tree_iter_first(&vma->anchor_page_rb,
+ 0, (unsigned long)-1);
+ node;) {
+ struct anchor_page_node *anchor_node = container_of(node,
+ struct anchor_page_node, node);
+ interval_tree_remove(node, &vma->anchor_page_rb);
+ node = interval_tree_iter_next(node, 0, (unsigned long)-1);
+ kfree(anchor_node);
+ }
+ }
+
+ /* no range at all */
+ if (RB_EMPTY_ROOT(&vma->anchor_page_rb.rb_root))
+ goto insert_new_range;
+
+ /* look for first range has start_addr or after it */
+ existing_anchor = interval_tree_iter_first(&vma->anchor_page_rb,
+ start_addr, end_addr);
+
+ /* first range has start_addr or after it */
+ if (existing_anchor) {
+ /* redundant range, do nothing */
+ if (existing_anchor->start == start_addr)
+ return 0;
+ else if (existing_anchor->start < start_addr &&
+ existing_anchor->last >= start_addr){
+ return 0;
+ } else { /* a range after start_addr */
+ struct anchor_page_node *existing_node = container_of(existing_anchor,
+ struct anchor_page_node, node);
+ VM_BUG_ON(!(existing_anchor->start > start_addr));
+ /* remove the existing range and insert a new one, since expanding
+ * forward can make the range go beyond the zone limit
+ */
+ interval_tree_remove(existing_anchor, &vma->anchor_page_rb);
+ kfree(existing_node);
+ VM_BUG_ON(!RB_EMPTY_ROOT(&vma->anchor_page_rb.rb_root));
+ goto insert_new_range;
+ }
+ } else {
+ struct interval_tree_node *prev_anchor = NULL, *cur_anchor;
+ /* there is a range before start_addr */
+
+ /* find the range just before start_addr */
+ for (cur_anchor = interval_tree_iter_first(&vma->anchor_page_rb,
+ vma->vm_start, start_addr - PAGE_SIZE);
+ cur_anchor;
+ prev_anchor = cur_anchor,
+ cur_anchor = interval_tree_iter_next(cur_anchor,
+ vma->vm_start, start_addr - PAGE_SIZE));
+
+ interval_tree_remove(prev_anchor, &vma->anchor_page_rb);
+ prev_anchor->last = vma->vm_end;
+ interval_tree_insert(prev_anchor, &vma->anchor_page_rb);
+
+ goto out;
+ }
+
+insert_new_range: /* start_addr to end_addr */
+ down_read(&vma->vm_mm->mmap_sem);
+ /* find the first present page and use it as the anchor page */
+ while (!present_page && scan_address < end_addr) {
+ present_page = follow_page(vma, scan_address,
+ FOLL_MIGRATION | FOLL_REMOTE);
+ scan_address += present_page?get_contig_page_size(present_page):PAGE_SIZE;
+ }
+ up_read(&vma->vm_mm->mmap_sem);
+
+ if (!present_page)
+ goto out;
+
+ anchor_node =
+ kmalloc(sizeof(struct anchor_page_node), GFP_KERNEL | __GFP_ZERO);
+ if (!anchor_node)
+ return -ENOMEM;
+
+ present_zone = page_zone(present_page);
+
+ anchor_node->node.start = start_addr;
+ anchor_node->node.last = end_addr;
+
+ anchor_node->anchor_vpn = start_addr>>PAGE_SHIFT;
+ anchor_node->anchor_pfn = get_undefragged_area(present_zone,
+ vma, start_addr, end_addr);
+
+ /* adjust VPN and PFN alignment according to VMA size */
+ if (vma->vm_end - vma->vm_start >= HPAGE_PUD_SIZE) {
+ if ((anchor_node->anchor_vpn & ((HPAGE_PUD_SIZE>>PAGE_SHIFT) - 1)) <
+ (anchor_node->anchor_pfn & ((HPAGE_PUD_SIZE>>PAGE_SHIFT) - 1)))
+ anchor_node->anchor_pfn += (HPAGE_PUD_SIZE>>PAGE_SHIFT);
+
+ anchor_node->anchor_pfn = (anchor_node->anchor_pfn & (PUD_MASK>>PAGE_SHIFT)) |
+ (anchor_node->anchor_vpn & ((HPAGE_PUD_SIZE>>PAGE_SHIFT) - 1));
+
+ alignment_size = HPAGE_PUD_SIZE;
+ } else if (vma->vm_end - vma->vm_start >= HPAGE_PMD_SIZE) {
+ if ((anchor_node->anchor_vpn & ((HPAGE_PMD_SIZE>>PAGE_SHIFT) - 1)) <
+ (anchor_node->anchor_pfn & ((HPAGE_PMD_SIZE>>PAGE_SHIFT) - 1)))
+ anchor_node->anchor_pfn += (HPAGE_PMD_SIZE>>PAGE_SHIFT);
+
+ anchor_node->anchor_pfn = (anchor_node->anchor_pfn & (PMD_MASK>>PAGE_SHIFT)) |
+ (anchor_node->anchor_vpn & ((HPAGE_PMD_SIZE>>PAGE_SHIFT) - 1));
+
+ alignment_size = HPAGE_PMD_SIZE;
+ } else
+ alignment_size = PAGE_SIZE;
+
+ /* move the range into the zone limit */
+ if (!(zone_spans_pfn(present_zone, anchor_node->anchor_pfn))) {
+ while (anchor_node->anchor_pfn >= zone_end_pfn(present_zone))
+ anchor_node->anchor_pfn -= alignment_size / PAGE_SHIFT;
+ while (anchor_node->anchor_pfn < present_zone->zone_start_pfn)
+ anchor_node->anchor_pfn += alignment_size / PAGE_SHIFT;
+ }
+
+ interval_tree_insert(&anchor_node->node, &vma->anchor_page_rb);
+
+out:
+ return 0;
+}
+
+static inline bool is_stats_collection(enum mem_defrag_action action)
+{
+ switch (action) {
+ case MEM_DEFRAG_FULL_STATS:
+ case MEM_DEFRAG_CONTIG_STATS:
+ return true;
+ default:
+ return false;
+ }
+ return false;
+}
+
+/* comparator for sorting vma's lifetime */
+static int unsigned_long_cmp(const void *a, const void *b)
+{
+ const unsigned long *l = a, *r = b;
+
+ if (*l < *r)
+ return -1;
+ if (*l > *r)
+ return 1;
+ return 0;
+}
+
+/*
+ * scan all to-be-defragged VMA lifetime and calculate VMA defragmentation
+ * threshold.
+ */
+static void scan_all_vma_lifetime(struct defrag_scan_control *sc)
+{
+ struct mm_struct *mm = sc->mm;
+ struct vm_area_struct *vma = NULL;
+ unsigned long current_jiffies = jiffies; /* fix one jiffies */
+ unsigned int num_vma = 0, index = 0;
+ unsigned long *vma_scan_list = NULL;
+
+ down_read(&mm->mmap_sem);
+ for (vma = find_vma(mm, 0); vma; vma = vma->vm_next)
+ /* only care about to-be-defragged vmas */
+ if (mem_defrag_vma_check(vma))
+ ++num_vma;
+
+ vma_scan_list = kmalloc(num_vma*sizeof(unsigned long),
+ GFP_KERNEL | __GFP_ZERO);
+
+ if (ZERO_OR_NULL_PTR(vma_scan_list)) {
+ sc->vma_scan_threshold = 1;
+ goto out;
+ }
+
+ for (vma = find_vma(mm, 0); vma; vma = vma->vm_next)
+ /* only care about to-be-defragged vmas */
+ if (mem_defrag_vma_check(vma)) {
+ if (vma_scan_threshold_type == VMA_THRESHOLD_TYPE_TIME)
+ vma_scan_list[index] = current_jiffies - vma->vma_create_jiffies;
+ else if (vma_scan_threshold_type == VMA_THRESHOLD_TYPE_SIZE)
+ vma_scan_list[index] = vma->vm_end - vma->vm_start;
+ ++index;
+ if (index >= num_vma)
+ break;
+ }
+
+ sort(vma_scan_list, num_vma, sizeof(unsigned long),
+ unsigned_long_cmp, NULL);
+
+ index = (100 - vma_scan_percentile) * num_vma / 100;
+
+ sc->vma_scan_threshold = vma_scan_list[index];
+
+ kfree(vma_scan_list);
+out:
+ up_read(&mm->mmap_sem);
+}
+
+/*
+ * Scan single mm_struct.
+ * The function will down_read mmap_sem.
+ *
+ */
+static int kmem_defragd_scan_mm(struct defrag_scan_control *sc)
+{
+ struct mm_struct *mm = sc->mm;
+ struct vm_area_struct *vma = NULL;
+ unsigned long *scan_address = &sc->scan_address;
+ char *stats_buf = NULL;
+ int remain_buf_len = sc->buf_len;
+ int err = 0;
+ struct contig_stats contig_stats;
+
+
+ if (sc->out_buf &&
+ sc->buf_len) {
+ stats_buf = vzalloc(sc->buf_len);
+ if (!stats_buf)
+ goto breakouterloop;
+ }
+
+ /*down_read(&mm->mmap_sem);*/
+ if (unlikely(kmem_defragd_test_exit(mm)))
+ vma = NULL;
+ else {
+ /* get vma_scan_threshold */
+ if (!sc->vma_scan_threshold)
+ scan_all_vma_lifetime(sc);
+
+ vma = find_vma(mm, *scan_address);
+ }
+
+ for (; vma; vma = vma->vm_next) {
+ unsigned long vstart, vend;
+ struct anchor_page_node *anchor_node = NULL;
+ int scanned_chunks = 0;
+
+
+ if (unlikely(kmem_defragd_test_exit(mm)))
+ break;
+ if (!mem_defrag_vma_check(vma)) {
+ /* collect contiguity stats for this VMA */
+ if (is_stats_collection(sc->action))
+ if (do_vma_stat(mm, vma, stats_buf, sc->buf_len - remain_buf_len,
+ &remain_buf_len))
+ goto breakouterloop;
+ *scan_address = vma->vm_end;
+ goto done_one_vma;
+ }
+
+
+ vstart = vma->vm_start;
+ vend = vma->vm_end;
+ if (vstart >= vend)
+ goto done_one_vma;
+ if (*scan_address > vend)
+ goto done_one_vma;
+ if (*scan_address < vstart)
+ *scan_address = vstart;
+
+ if (sc->action == MEM_DEFRAG_DO_DEFRAG) {
+ /* Check VMA size, skip if below the size threshold */
+ if (vma->vm_end - vma->vm_start <
+ defrag_size_threshold * HPAGE_PMD_SIZE)
+ goto done_one_vma;
+
+ /*
+ * Check VMA lifetime or size, skip if below the lifetime/size
+ * threshold derived from a percentile
+ */
+ if (vma_scan_threshold_type == VMA_THRESHOLD_TYPE_TIME) {
+ if ((jiffies - vma->vma_create_jiffies) < sc->vma_scan_threshold)
+ goto done_one_vma;
+ } else if (vma_scan_threshold_type == VMA_THRESHOLD_TYPE_SIZE) {
+ if ((vma->vm_end - vma->vm_start) < sc->vma_scan_threshold)
+ goto done_one_vma;
+ }
+
+ /* Avoid repeated defrag if the vma has not been changed */
+ if (vma_no_repeat_defrag &&
+ vma->vma_defrag_jiffies > vma->vma_modify_jiffies)
+ goto done_one_vma;
+
+ /* vma contiguity stats collection */
+ if (remain_buf_len && stats_buf) {
+ int used_len;
+ int pos = sc->buf_len - remain_buf_len;
+
+ used_len = scnprintf(stats_buf + pos, remain_buf_len,
+ "vma: 0x%lx, 0x%lx, 0x%lx, -1\n",
+ (unsigned long)vma+vma->vma_create_jiffies,
+ vma->vm_start, vma->vm_end);
+
+ remain_buf_len -= used_len;
+
+ if (remain_buf_len == 1) {
+ stats_buf[pos] = '\0';
+ remain_buf_len = 0;
+ }
+ }
+
+ anchor_node = get_anchor_page_node_from_vma(vma, vma->vm_start);
+
+ if (!anchor_node) {
+ find_anchor_pages_in_vma(mm, vma, vma->vm_start);
+ anchor_node = get_anchor_page_node_from_vma(vma, vma->vm_start);
+
+ if (!anchor_node)
+ goto done_one_vma;
+ }
+ }
+
+ contig_stats = (struct contig_stats) {0};
+
+ while (*scan_address < vend) {
+ struct page *page;
+
+ cond_resched();
+
+ if (unlikely(kmem_defragd_test_exit(mm)))
+ goto breakouterloop;
+
+ if (is_stats_collection(sc->action)) {
+ down_read(&vma->vm_mm->mmap_sem);
+ page = follow_page(vma, *scan_address,
+ FOLL_MIGRATION | FOLL_REMOTE);
+
+ if (do_page_stat(mm, vma, page, *scan_address,
+ stats_buf, sc->buf_len - remain_buf_len,
+ &remain_buf_len, sc->action, &contig_stats,
+ sc->scan_in_vma)) {
+ /* reset scan_address to the beginning of the contig.
+ * So next scan will get the whole contig.
+ */
+ if (contig_stats.err) {
+ *scan_address = contig_stats.first_vaddr_in_chunk;
+ sc->scan_in_vma = true;
+ }
+ goto breakouterloop;
+ }
+ /* move to next address */
+ if (page)
+ *scan_address += get_contig_page_size(page);
+ else
+ *scan_address += PAGE_SIZE;
+ up_read(&vma->vm_mm->mmap_sem);
+ } else if (sc->action == MEM_DEFRAG_DO_DEFRAG) {
+ /* go to nearest 1GB aligned address */
+ unsigned long defrag_end = min_t(unsigned long,
+ (*scan_address + HPAGE_PUD_SIZE) & HPAGE_PUD_MASK,
+ vend);
+ int defrag_result;
+
+ anchor_node = get_anchor_page_node_from_vma(vma, *scan_address);
+
+ /* in case VMA size changes */
+ if (!anchor_node) {
+ find_anchor_pages_in_vma(mm, vma, *scan_address);
+ anchor_node = get_anchor_page_node_from_vma(vma, *scan_address);
+ }
+
+ if (!anchor_node)
+ goto done_one_vma;
+
+ /*
+ * looping through the 1GB region and defrag 2MB range in each
+ * iteration.
+ */
+ while (*scan_address < defrag_end) {
+ unsigned long defrag_sub_chunk_end = min_t(unsigned long,
+ (*scan_address + HPAGE_PMD_SIZE) & HPAGE_PMD_MASK,
+ defrag_end);
+ struct defrag_result_stats defrag_stats = {0};
+continue_defrag:
+ if (!anchor_node) {
+ anchor_node = get_anchor_page_node_from_vma(vma,
+ *scan_address);
+ if (!anchor_node) {
+ find_anchor_pages_in_vma(mm, vma, *scan_address);
+ anchor_node = get_anchor_page_node_from_vma(vma,
+ *scan_address);
+ }
+ if (!anchor_node)
+ goto done_one_vma;
+ }
+
+ defrag_result = defrag_address_range(mm, vma, *scan_address,
+ defrag_sub_chunk_end,
+ pfn_to_page(anchor_node->anchor_pfn),
+ anchor_node->anchor_vpn<<PAGE_SHIFT,
+ &defrag_stats);
+
+ /*
+ * collect defrag results to show the cause of page
+ * migration/exchange failure
+ */
+ if (remain_buf_len && stats_buf) {
+ int used_len;
+ int pos = sc->buf_len - remain_buf_len;
+
+ used_len = scnprintf(stats_buf + pos, remain_buf_len,
+ "[0x%lx, 0x%lx):%lu [alig:%lu, migrated:%lu, "
+ "src: not:%lu, src_thp_dst_not:%lu, src_pte_thp:%lu "
+ "dst: out_bound:%lu, dst_thp_src_not:%lu, "
+ "dst_pte_thp:%lu, isolate_free:%lu, "
+ "migrate_free:%lu, anon:%lu, file:%lu, "
+ "non-lru:%lu, non-moveable:%lu], "
+ "anchor: (%lx, %lx), range: [%lx, %lx], "
+ "vma: 0x%lx, not_defrag_vpn: %lx\n",
+ *scan_address, defrag_sub_chunk_end,
+ (defrag_sub_chunk_end - *scan_address)/PAGE_SIZE,
+ defrag_stats.aligned,
+ defrag_stats.migrated,
+ defrag_stats.src_not_present,
+ defrag_stats.src_thp_dst_not_failed,
+ defrag_stats.src_pte_thp_failed,
+ defrag_stats.dst_out_of_bound_failed,
+ defrag_stats.dst_thp_src_not_failed,
+ defrag_stats.dst_pte_thp_failed,
+ defrag_stats.dst_isolate_free_failed,
+ defrag_stats.dst_migrate_free_failed,
+ defrag_stats.dst_anon_failed,
+ defrag_stats.dst_file_failed,
+ defrag_stats.dst_non_lru_failed,
+ defrag_stats.dst_non_moveable_failed,
+ anchor_node->anchor_vpn,
+ anchor_node->anchor_pfn,
+ anchor_node->node.start,
+ anchor_node->node.last,
+ (unsigned long)vma+vma->vma_create_jiffies,
+ defrag_stats.not_defrag_vpn
+ );
+
+ remain_buf_len -= used_len;
+
+ if (remain_buf_len == 1) {
+ stats_buf[pos] = '\0';
+ remain_buf_len = 0;
+ }
+ }
+
+ /*
+ * skip the page which cannot be defragged and restart
+ * from the next page
+ */
+ if (defrag_stats.not_defrag_vpn &&
+ defrag_stats.not_defrag_vpn < defrag_sub_chunk_end) {
+ VM_BUG_ON(defrag_sub_chunk_end != defrag_end &&
+ defrag_stats.not_defrag_vpn > defrag_sub_chunk_end);
+
+ *scan_address = defrag_stats.not_defrag_vpn;
+ defrag_stats.not_defrag_vpn = 0;
+ goto continue_defrag;
+ }
+
+ /* Done with current 2MB chunk */
+ *scan_address = defrag_sub_chunk_end;
+ scanned_chunks++;
+ /*
+ * if the knob is set, break out of the defrag loop after
+ * a preset number of 2MB chunks are defragged
+ */
+ if (num_breakout_chunks && scanned_chunks >= num_breakout_chunks) {
+ scanned_chunks = 0;
+ goto breakouterloop;
+ }
+ }
+
+ }
+ }
+done_one_vma:
+ sc->scan_in_vma = false;
+ if (sc->action == MEM_DEFRAG_DO_DEFRAG)
+ vma->vma_defrag_jiffies = jiffies;
+ }
+breakouterloop:
+
+ /* copy stats to user space */
+ if (sc->out_buf &&
+ sc->buf_len) {
+ err = copy_to_user(sc->out_buf, stats_buf,
+ sc->buf_len - remain_buf_len);
+ sc->used_len = sc->buf_len - remain_buf_len;
+ }
+
+ if (stats_buf)
+ vfree(stats_buf);
+
+ /* 0: scan a vma complete, 1: scan a vma incomplete */
+ return vma == NULL ? 0 : 1;
+}
+
+SYSCALL_DEFINE4(scan_process_memory, pid_t, pid, char __user *, out_buf,
+ int, buf_len, int, action)
+{
+ const struct cred *cred = current_cred(), *tcred;
+ struct task_struct *task;
+ struct mm_struct *mm;
+ int err = 0;
+ static struct defrag_scan_control defrag_scan_control = {0};
+
+ /* Find the mm_struct */
+ rcu_read_lock();
+ task = pid ? find_task_by_vpid(pid) : current;
+ if (!task) {
+ rcu_read_unlock();
+ return -ESRCH;
+ }
+ get_task_struct(task);
+
+ /*
+ * 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;
+ }
+ rcu_read_unlock();
+
+ err = security_task_movememory(task);
+ if (err)
+ goto out;
+
+ mm = get_task_mm(task);
+ put_task_struct(task);
+
+ if (!mm)
+ return -EINVAL;
+
+ switch (action) {
+ case MEM_DEFRAG_SCAN:
+ case MEM_DEFRAG_CONTIG_SCAN:
+ count_vm_event(MEM_DEFRAG_SCAN_NUM);
+ /*
+ * We allow scanning one process's address space for multiple
+ * iterations. When we change the scanned process, reset
+ * defrag_scan_control's mm_struct
+ */
+ if (!defrag_scan_control.mm ||
+ defrag_scan_control.mm != mm) {
+ defrag_scan_control = (struct defrag_scan_control){0};
+ defrag_scan_control.mm = mm;
+ }
+ defrag_scan_control.out_buf = out_buf;
+ defrag_scan_control.buf_len = buf_len;
+ if (action == MEM_DEFRAG_SCAN)
+ defrag_scan_control.action = MEM_DEFRAG_FULL_STATS;
+ else if (action == MEM_DEFRAG_CONTIG_SCAN)
+ defrag_scan_control.action = MEM_DEFRAG_CONTIG_STATS;
+ else {
+ err = -EINVAL;
+ break;
+ }
+
+ defrag_scan_control.used_len = 0;
+
+ if (unlikely(!access_ok(out_buf, buf_len))) {
+ err = -EFAULT;
+ break;
+ }
+
+ /* clear mm once it is fully scanned */
+ if (!kmem_defragd_scan_mm(&defrag_scan_control) &&
+ !defrag_scan_control.used_len)
+ defrag_scan_control.mm = NULL;
+
+ err = defrag_scan_control.used_len;
+ break;
+ case MEM_DEFRAG_MARK_SCAN_ALL:
+ set_bit(MMF_VM_MEM_DEFRAG_ALL, &mm->flags);
+ __kmem_defragd_enter(mm);
+ break;
+ case MEM_DEFRAG_CLEAR_SCAN_ALL:
+ clear_bit(MMF_VM_MEM_DEFRAG_ALL, &mm->flags);
+ break;
+ case MEM_DEFRAG_DEFRAG:
+ count_vm_event(MEM_DEFRAG_DEFRAG_NUM);
+
+ if (!defrag_scan_control.mm ||
+ defrag_scan_control.mm != mm) {
+ defrag_scan_control = (struct defrag_scan_control){0};
+ defrag_scan_control.mm = mm;
+ }
+ defrag_scan_control.action = MEM_DEFRAG_DO_DEFRAG;
+
+ defrag_scan_control.out_buf = out_buf;
+ defrag_scan_control.buf_len = buf_len;
+
+ /* clear mm once it is fully defragged */
+ if (buf_len) {
+ if (!kmem_defragd_scan_mm(&defrag_scan_control) &&
+ !defrag_scan_control.used_len) {
+ defrag_scan_control.mm = NULL;
+ }
+ err = defrag_scan_control.used_len;
+ } else {
+ err = kmem_defragd_scan_mm(&defrag_scan_control);
+ if (err == 0)
+ defrag_scan_control.mm = NULL;
+ }
+ break;
+ default:
+ err = -EINVAL;
+ break;
+ }
+
+ mmput(mm);
+ return err;
+
+out:
+ put_task_struct(task);
+ return err;
+}
+
+static unsigned int kmem_defragd_scan_mm_slot(void)
+{
+ struct mm_slot *mm_slot;
+ int scan_status = 0;
+ struct defrag_scan_control defrag_scan_control = {0};
+
+ spin_lock(&kmem_defragd_mm_lock);
+ if (kmem_defragd_scan.mm_slot)
+ mm_slot = kmem_defragd_scan.mm_slot;
+ else {
+ mm_slot = list_entry(kmem_defragd_scan.mm_head.next,
+ struct mm_slot, mm_node);
+ kmem_defragd_scan.address = 0;
+ kmem_defragd_scan.mm_slot = mm_slot;
+ }
+ spin_unlock(&kmem_defragd_mm_lock);
+
+ defrag_scan_control.mm = mm_slot->mm;
+ defrag_scan_control.scan_address = kmem_defragd_scan.address;
+ defrag_scan_control.action = MEM_DEFRAG_DO_DEFRAG;
+
+ scan_status = kmem_defragd_scan_mm(&defrag_scan_control);
+
+ kmem_defragd_scan.address = defrag_scan_control.scan_address;
+
+ spin_lock(&kmem_defragd_mm_lock);
+ VM_BUG_ON(kmem_defragd_scan.mm_slot != mm_slot);
+ /*
+ * Release the current mm_slot if this mm is about to die, or
+ * if we scanned all vmas of this mm.
+ */
+ if (kmem_defragd_test_exit(mm_slot->mm) || !scan_status) {
+ /*
+ * Make sure that if mm_users is reaching zero while
+ * kmem_defragd runs here, kmem_defragd_exit will find
+ * mm_slot not pointing to the exiting mm.
+ */
+ if (mm_slot->mm_node.next != &kmem_defragd_scan.mm_head) {
+ kmem_defragd_scan.mm_slot = list_first_entry(
+ &mm_slot->mm_node,
+ struct mm_slot, mm_node);
+ kmem_defragd_scan.address = 0;
+ } else
+ kmem_defragd_scan.mm_slot = NULL;
+
+ if (kmem_defragd_test_exit(mm_slot->mm))
+ collect_mm_slot(mm_slot);
+ else if (!scan_status) {
+ list_del(&mm_slot->mm_node);
+ list_add_tail(&mm_slot->mm_node, &kmem_defragd_scan.mm_head);
+ }
+ }
+ spin_unlock(&kmem_defragd_mm_lock);
+
+ return 0;
+}
+
+int memdefrag_madvise(struct vm_area_struct *vma,
+ unsigned long *vm_flags, int advice)
+{
+ switch (advice) {
+ case MADV_MEMDEFRAG:
+ *vm_flags &= ~VM_NOMEMDEFRAG;
+ *vm_flags |= VM_MEMDEFRAG;
+ /*
+ * If the vma become good for kmem_defragd to scan,
+ * register it here without waiting a page fault that
+ * may not happen any time soon.
+ */
+ if (kmem_defragd_enter(vma, *vm_flags))
+ return -ENOMEM;
+ break;
+ case MADV_NOMEMDEFRAG:
+ *vm_flags &= ~VM_MEMDEFRAG;
+ *vm_flags |= VM_NOMEMDEFRAG;
+ /*
+ * Setting VM_NOMEMDEFRAG will prevent kmem_defragd from scanning
+ * this vma even if we leave the mm registered in kmem_defragd if
+ * it got registered before VM_NOMEMDEFRAG was set.
+ */
+ break;
+ }
+
+ return 0;
+}
+
+
+void __init kmem_defragd_destroy(void)
+{
+ kmem_cache_destroy(mm_slot_cache);
+}
+
+int __init kmem_defragd_init(void)
+{
+ mm_slot_cache = kmem_cache_create("kmem_defragd_mm_slot",
+ sizeof(struct mm_slot),
+ __alignof__(struct mm_slot), 0, NULL);
+ if (!mm_slot_cache)
+ return -ENOMEM;
+
+ return 0;
+}
+
+subsys_initcall(kmem_defragd_init);
\ No newline at end of file
diff --git a/mm/memory.c b/mm/memory.c
index e11ca9dd823f..019036e87088 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -69,6 +69,7 @@
#include <linux/userfaultfd_k.h>
#include <linux/dax.h>
#include <linux/oom.h>
+#include <linux/mem_defrag.h>

#include <asm/io.h>
#include <asm/mmu_context.h>
@@ -2926,6 +2927,9 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
/* Allocate our own private page. */
if (unlikely(anon_vma_prepare(vma)))
goto oom;
+ /* Make it defrag */
+ if (unlikely(kmem_defragd_enter(vma, vma->vm_flags)))
+ goto oom;
page = alloc_zeroed_user_highpage_movable(vma, vmf->address);
if (!page)
goto oom;
@@ -3844,6 +3848,9 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma,
p4d_t *p4d;
vm_fault_t ret;

+ /* Zi: page faults modify vma */
+ vma->vma_modify_jiffies = jiffies;
+
pgd = pgd_offset(mm, address);
p4d = p4d_alloc(mm, pgd, address);
if (!p4d)
diff --git a/mm/mmap.c b/mm/mmap.c
index f901065c4c64..653dd99d5145 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -169,6 +169,28 @@ void unlink_file_vma(struct vm_area_struct *vma)
}
}

+void free_anchor_pages(struct vm_area_struct *vma)
+{
+ struct interval_tree_node *node;
+
+ if (!vma)
+ return;
+
+ if (RB_EMPTY_ROOT(&vma->anchor_page_rb.rb_root))
+ return;
+
+ for (node = interval_tree_iter_first(&vma->anchor_page_rb,
+ 0, (unsigned long)-1);
+ node;) {
+ struct anchor_page_node *anchor_node = container_of(node,
+ struct anchor_page_node, node);
+ interval_tree_remove(node, &vma->anchor_page_rb);
+ node = interval_tree_iter_next(node, 0, (unsigned long)-1);
+ kfree(anchor_node);
+ }
+
+}
+
/*
* Close a vm structure and free it, returning the next.
*/
@@ -181,6 +203,7 @@ static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
vma->vm_ops->close(vma);
if (vma->vm_file)
fput(vma->vm_file);
+ free_anchor_pages(vma);
mpol_put(vma_policy(vma));
vm_area_free(vma);
return next;
@@ -725,10 +748,15 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
long adjust_next = 0;
int remove_next = 0;

+ /*free_anchor_pages(vma);*/
+
+ vma->vma_modify_jiffies = jiffies;
+
if (next && !insert) {
struct vm_area_struct *exporter = NULL, *importer = NULL;

if (end >= next->vm_end) {
+ /*free_anchor_pages(next);*/
/*
* vma expands, overlapping all the next, and
* perhaps the one after too (mprotect case 6).
@@ -775,6 +803,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
exporter = next->vm_next;

} else if (end > next->vm_start) {
+ /*free_anchor_pages(next);*/
/*
* vma expands, overlapping part of the next:
* mprotect case 5 shifting the boundary up.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 35fdde041f5c..a35605e0924a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1828,7 +1828,7 @@ void __init init_cma_reserved_pageblock(struct page *page)
*
* -- nyc
*/
-static inline void expand(struct zone *zone, struct page *page,
+inline void expand(struct zone *zone, struct page *page,
int low, int high, struct free_area *area,
int migratetype)
{
@@ -1950,7 +1950,7 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
set_page_owner(page, order, gfp_flags);
}

-static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
+void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
unsigned int alloc_flags)
{
int i;
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 83b30edc2f7f..c18a42250a5c 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1293,6 +1293,27 @@ const char * const vmstat_text[] = {
"swap_ra",
"swap_ra_hit",
#endif
+ "memdefrag_defrag",
+ "memdefrag_scan",
+ "memdefrag_dest_free_pages",
+ "memdefrag_dest_anon_pages",
+ "memdefrag_dest_file_pages",
+ "memdefrag_dest_non_lru_pages",
+ "memdefrag_dest_free_pages_failed",
+ "memdefrag_dest_free_pages_overflow_failed",
+ "memdefrag_dest_anon_pages_failed",
+ "memdefrag_dest_file_pages_failed",
+ "memdefrag_dest_nonlru_pages_failed",
+ "memdefrag_src_anon_pages_failed",
+ "memdefrag_src_compound_pages_failed",
+ "memdefrag_dst_split_hugepage",
+#ifdef CONFIG_COMPACTION
+ "compact_migrate_pages",
+#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ "thp_collapse_migrate_pages"
+#endif
+
#endif /* CONFIG_VM_EVENTS_COUNTERS */
};
#endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */
--
2.20.1