[RFC 4/6] memtrack: Adds the accounting to keep track of all mmaped/unmapped pages.

From: Ruchi Kandoi
Date: Tue Oct 11 2016 - 19:52:35 EST

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Since mmaped pages will be accounted by the PSS, memtrack needs a way
to differentiate the total memory that hasn't been accounted for.

Signed-off-by: Ruchi Kandoi <kandoiruchi@xxxxxxxxxx>
Signed-off-by: Greg Hackmann <ghackmann@xxxxxxxxxx>
---
drivers/misc/memtrack.c | 175 ++++++++++++++++++++++++++++++++------
drivers/staging/android/ion/ion.c | 5 +-
include/linux/memtrack.h | 29 +++++++
3 files changed, 180 insertions(+), 29 deletions(-)

diff --git a/drivers/misc/memtrack.c b/drivers/misc/memtrack.c
index e5c7e03..4b2d17f 100644
--- a/drivers/misc/memtrack.c
+++ b/drivers/misc/memtrack.c
@@ -22,12 +22,19 @@
#include <linux/rbtree.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
+#include <linux/mm.h>
+
+struct memtrack_vma_list {
+ struct hlist_node node;
+ const struct vm_area_struct *vma;
+};

struct memtrack_handle {
struct memtrack_buffer *buffer;
struct rb_node node;
struct rb_root *root;
struct kref refcount;
+ struct hlist_head vma_list;
};

static struct kmem_cache *memtrack_handle_cache;
@@ -40,8 +47,8 @@ static DEFINE_IDR(mem_idr);
static DEFINE_IDA(mem_ida);
#endif

-static void memtrack_buffer_install_locked(struct rb_root *root,
- struct memtrack_buffer *buffer)
+static struct memtrack_handle *memtrack_handle_find_locked(struct rb_root *root,
+ struct memtrack_buffer *buffer, bool alloc)
{
struct rb_node **new = &root->rb_node, *parent = NULL;
struct memtrack_handle *handle;
@@ -56,22 +63,38 @@ static void memtrack_buffer_install_locked(struct rb_root *root,
} else if (handle->buffer->id < buffer->id) {
new = &node->rb_right;
} else {
- kref_get(&handle->refcount);
- return;
+ return handle;
}
}

- handle = kmem_cache_alloc(memtrack_handle_cache, GFP_KERNEL);
- if (!handle)
- return;
+ if (alloc) {
+ handle = kmem_cache_alloc(memtrack_handle_cache, GFP_KERNEL);
+ if (!handle)
+ return NULL;

- handle->buffer = buffer;
- handle->root = root;
- kref_init(&handle->refcount);
+ handle->buffer = buffer;
+ handle->root = root;
+ kref_init(&handle->refcount);
+ INIT_HLIST_HEAD(&handle->vma_list);

- rb_link_node(&handle->node, parent, new);
- rb_insert_color(&handle->node, root);
- atomic_inc(&handle->buffer->userspace_handles);
+ rb_link_node(&handle->node, parent, new);
+ rb_insert_color(&handle->node, root);
+ atomic_inc(&handle->buffer->userspace_handles);
+ }
+
+ return NULL;
+}
+
+static void memtrack_buffer_install_locked(struct rb_root *root,
+ struct memtrack_buffer *buffer)
+{
+ struct memtrack_handle *handle;
+
+ handle = memtrack_handle_find_locked(root, buffer, true);
+ if (handle) {
+ kref_get(&handle->refcount);
+ return;
+ }
}

/**
@@ -112,19 +135,41 @@ static void memtrack_handle_destroy(struct kref *ref)
static void memtrack_buffer_uninstall_locked(struct rb_root *root,
struct memtrack_buffer *buffer)
{
- struct rb_node *node = root->rb_node;
+ struct memtrack_handle *handle;

- while (node) {
- struct memtrack_handle *handle = rb_entry(node,
- struct memtrack_handle, node);
+ handle = memtrack_handle_find_locked(root, buffer, false);

- if (handle->buffer->id > buffer->id) {
- node = node->rb_left;
- } else if (handle->buffer->id < buffer->id) {
- node = node->rb_right;
- } else {
- kref_put(&handle->refcount, memtrack_handle_destroy);
- return;
+ if (handle)
+ kref_put(&handle->refcount, memtrack_handle_destroy);
+}
+
+static void memtrack_buffer_vm_open_locked(struct rb_root *root,
+ struct memtrack_buffer *buffer,
+ struct memtrack_vma_list *vma_list)
+{
+ struct memtrack_handle *handle;
+
+ handle = memtrack_handle_find_locked(root, buffer, false);
+ if (handle)
+ hlist_add_head(&vma_list->node, &handle->vma_list);
+}
+
+static void memtrack_buffer_vm_close_locked(struct rb_root *root,
+ struct memtrack_buffer *buffer,
+ const struct vm_area_struct *vma)
+{
+ struct memtrack_handle *handle;
+
+ handle = memtrack_handle_find_locked(root, buffer, false);
+ if (handle) {
+ struct memtrack_vma_list *vma_list;
+
+ hlist_for_each_entry(vma_list, &handle->vma_list, node) {
+ if (vma_list->vma == vma) {
+ hlist_del(&vma_list->node);
+ kfree(vma_list);
+ return;
+ }
}
}
}
@@ -153,6 +198,49 @@ void memtrack_buffer_uninstall(struct memtrack_buffer *buffer,
}
EXPORT_SYMBOL(memtrack_buffer_uninstall);

+/**
+ * memtrack_buffer_vm_open - account for pages mapped during vm open
+ *
+ * @buffer: the buffer's memtrack entry
+ *
+ * @vma: vma being opened
+ */
+void memtrack_buffer_vm_open(struct memtrack_buffer *buffer,
+ const struct vm_area_struct *vma)
+{
+ unsigned long flags;
+ struct task_struct *leader = current->group_leader;
+ struct memtrack_vma_list *vma_list;
+
+ vma_list = kmalloc(sizeof(*vma_list), GFP_KERNEL);
+ if (WARN_ON(!vma_list))
+ return;
+ vma_list->vma = vma;
+
+ write_lock_irqsave(&leader->memtrack_lock, flags);
+ memtrack_buffer_vm_open_locked(&leader->memtrack_rb, buffer, vma_list);
+ write_unlock_irqrestore(&leader->memtrack_lock, flags);
+}
+EXPORT_SYMBOL(memtrack_buffer_vm_open);
+
+/**
+ * memtrack_buffer_vm_close - account for pages unmapped during vm close
+ *
+ * @buffer: the buffer's memtrack entry
+ * @vma: the vma being closed
+ */
+void memtrack_buffer_vm_close(struct memtrack_buffer *buffer,
+ const struct vm_area_struct *vma)
+{
+ unsigned long flags;
+ struct task_struct *leader = current->group_leader;
+
+ write_lock_irqsave(&leader->memtrack_lock, flags);
+ memtrack_buffer_vm_close_locked(&leader->memtrack_rb, buffer, vma);
+ write_unlock_irqrestore(&leader->memtrack_lock, flags);
+}
+EXPORT_SYMBOL(memtrack_buffer_vm_close);
+
static int memtrack_id_alloc(struct memtrack_buffer *buffer)
{
int ret;
@@ -271,6 +359,33 @@ static struct notifier_block process_notifier_block = {
.notifier_call = process_notifier,
};

+static void show_memtrack_vma(struct seq_file *m,
+ const struct vm_area_struct *vma,
+ const struct memtrack_buffer *buf)
+{
+ unsigned long start = vma->vm_start;
+ unsigned long end = vma->vm_end;
+ unsigned long long pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
+ vm_flags_t flags = vma->vm_flags;
+ vm_flags_t remap_flag = VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
+
+ seq_setwidth(m, 50);
+ seq_printf(m, "%68lx-%08lx %c%c%c%c%c %08llx",
+ start,
+ end,
+ flags & VM_READ ? 'r' : '-',
+ flags & VM_WRITE ? 'w' : '-',
+ flags & VM_EXEC ? 'x' : '-',
+ flags & VM_MAYSHARE ? 's' : 'p',
+ flags & remap_flag ? '#' : '-',
+ pgoff);
+ if (buf->tag) {
+ seq_pad(m, ' ');
+ seq_puts(m, buf->tag);
+ }
+ seq_putc(m, '\n');
+}
+
int proc_memtrack(struct seq_file *m, struct pid_namespace *ns, struct pid *pid,
struct task_struct *task)
{
@@ -281,18 +396,23 @@ int proc_memtrack(struct seq_file *m, struct pid_namespace *ns, struct pid *pid,
if (RB_EMPTY_ROOT(&task->memtrack_rb))
goto done;

- seq_printf(m, "%10.10s: %16.16s: %12.12s: %3.3s: pid:%d\n",
- "ref_count", "Identifier", "size", "tag", task->pid);
+ seq_printf(m, "%10.10s: %16.16s: %12.12s: %12.12s: %20s: %5s: %8s: pid:%d\n",
+ "ref_count", "Identifier", "size", "tag",
+ "startAddr-endAddr", "Flags", "pgOff", task->pid);

for (node = rb_first(&task->memtrack_rb); node; node = rb_next(node)) {
struct memtrack_handle *handle = rb_entry(node,
struct memtrack_handle, node);
struct memtrack_buffer *buffer = handle->buffer;
+ struct memtrack_vma_list *vma;

- seq_printf(m, "%10d %16d %12zu %s\n",
+ seq_printf(m, "%10d %16d %12zu %12s\n",
atomic_read(&buffer->userspace_handles),
buffer->id, buffer->size,
buffer->tag ? buffer->tag : "");
+
+ hlist_for_each_entry(vma, &handle->vma_list, node)
+ show_memtrack_vma(m, vma->vma, handle->buffer);
}

done:
@@ -308,7 +428,6 @@ static int memtrack_show(struct seq_file *m, void *v)

seq_printf(m, "%4.4s %12.12s %10s %12.12s %3.3s\n", "pid",
"buffer_size", "ref", "Identifier", "tag");
-
rcu_read_lock();
idr_for_each_entry(&mem_idr, buffer, i)
seq_printf(m, "%4d %12zu %10d %12d %s\n", buffer->pid,
diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index 1c2df54..c32d520 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -906,6 +906,7 @@ static void ion_vm_open(struct vm_area_struct *vma)
list_add(&vma_list->list, &buffer->vmas);
mutex_unlock(&buffer->lock);
pr_debug("%s: adding %p\n", __func__, vma);
+ memtrack_buffer_vm_open(&buffer->memtrack_buffer, vma);
}

static void ion_vm_close(struct vm_area_struct *vma)
@@ -924,6 +925,7 @@ static void ion_vm_close(struct vm_area_struct *vma)
break;
}
mutex_unlock(&buffer->lock);
+ memtrack_buffer_vm_close(&buffer->memtrack_buffer, vma);
}

static const struct vm_operations_struct ion_vma_ops = {
@@ -963,7 +965,8 @@ static int ion_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
if (ret)
pr_err("%s: failure mapping buffer to userspace\n",
__func__);
-
+ else
+ memtrack_buffer_mmap(dma_buf_memtrack_buffer(dmabuf), vma);
return ret;
}

diff --git a/include/linux/memtrack.h b/include/linux/memtrack.h
index f73be07..5a4c7ea 100644
--- a/include/linux/memtrack.h
+++ b/include/linux/memtrack.h
@@ -33,12 +33,18 @@ struct memtrack_buffer {

int proc_memtrack(struct seq_file *m, struct pid_namespace *ns, struct pid *pid,
struct task_struct *task);
+int proc_memtrack_maps(struct seq_file *m, struct pid_namespace *ns,
+ struct pid *pid, struct task_struct *task);
int memtrack_buffer_init(struct memtrack_buffer *buffer, size_t size);
void memtrack_buffer_remove(struct memtrack_buffer *buffer);
void memtrack_buffer_install(struct memtrack_buffer *buffer,
struct task_struct *tsk);
void memtrack_buffer_uninstall(struct memtrack_buffer *buffer,
struct task_struct *tsk);
+void memtrack_buffer_vm_open(struct memtrack_buffer *buffer,
+ const struct vm_area_struct *vma);
+void memtrack_buffer_vm_close(struct memtrack_buffer *buffer,
+ const struct vm_area_struct *vma);

/**
* memtrack_buffer_set_tag - add a descriptive tag to a memtrack entry
@@ -90,5 +96,28 @@ static inline int memtrack_buffer_set_tag(struct memtrack_buffer *buffer,
return -ENOENT;
}

+static inline void memtrack_buffer_vm_open(struct memtrack_buffer *buffer,
+ const struct vm_area_struct *vma)
+{
+}
+
+static inline void memtrack_buffer_vm_close(struct memtrack_buffer *buffer,
+ const struct vm_area_struct *vma)
+{
+}
#endif /* CONFIG_MEMTRACK */
+
+
+/**
+ * memtrack_buffer_vm_mmap - account for pages mapped to userspace during mmap
+ *
+ * @buffer: the buffer's memtrack entry
+ * @vma: the vma passed to mmap()
+ */
+static inline void memtrack_buffer_mmap(struct memtrack_buffer *buffer,
+ const struct vm_area_struct *vma)
+{
+ memtrack_buffer_vm_open(buffer, vma);
+}
+
#endif /* _MEMTRACK_ */
--
2.8.0.rc3.226.g39d4020

Next message: Baoquan He: "Re: [PATCH] kexec: Export memory sections virtual addresses to vmcoreinfo"
Previous message: Ruchi Kandoi: "[RFC 3/6] dma-buf: add memtrack support"
In reply to: Ruchi Kandoi: "[RFC 3/6] dma-buf: add memtrack support"
Next in thread: Al Viro: "Re: [RFC 0/6] Module for tracking/accounting shared memory buffers"
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