Revert "ANDROID: Track per-process dmabuf RSS HWM"

Revert submission 3680024

Reason for revert: replacing with a fixed version

Reverted changes: /q/submissionid:3680024

Bug: 430499939
Change-Id: I57d3532def7a03d4e785ec64ade727a43503a2fb
Signed-off-by: Suren Baghdasaryan <surenb@google.com>

drivers/dma-buf/dma-buf.c

@@ -187,14 +187,6 @@ static int new_task_dmabuf_record(struct task_struct *task, struct dma_buf *dmab
 		return -ENOMEM;
 
 	task->dmabuf_info->rss += dmabuf->size;
-	/*
-	 * task->dmabuf_info->lock protects against concurrent writers, so no
-	 * worries about stale rss_hwm between the read and write, and we don't
-	 * need to cmpxchg here.
-	 */
-	if (task->dmabuf_info->rss > task->dmabuf_info->rss_hwm)
-		task->dmabuf_info->rss_hwm = task->dmabuf_info->rss;
-
 	rec->dmabuf = dmabuf;
 	rec->refcnt = 1;
 	list_add(&rec->node, &task->dmabuf_info->dmabufs);

fs/proc/base.c

@@ -3321,82 +3321,6 @@ static int proc_dmabuf_rss_show(struct seq_file *m, struct pid_namespace *ns,
 
 	return 0;
 }
-
-static int proc_dmabuf_rss_hwm_show(struct seq_file *m, void *v)
-{
-	struct inode *inode = m->private;
-	struct task_struct *task;
-	int ret = 0;
-
-	task = get_proc_task(inode);
-	if (!task)
-		return -ESRCH;
-
-	if (!task->dmabuf_info) {
-		pr_err("%s dmabuf accounting record was not allocated\n", __func__);
-		ret = -ENOMEM;
-		goto out;
-	}
-
-	if (!(task->flags & PF_KTHREAD))
-		seq_printf(m, "%lld\n", READ_ONCE(task->dmabuf_info->rss_hwm));
-	else
-		seq_puts(m, "0\n");
-
-out:
-	put_task_struct(task);
-
-	return ret;
-}
-
-static int proc_dmabuf_rss_hwm_open(struct inode *inode, struct file *filp)
-{
-	return single_open(filp, proc_dmabuf_rss_hwm_show, inode);
-}
-
-static ssize_t
-proc_dmabuf_rss_hwm_write(struct file *file, const char __user *buf,
-			  size_t count, loff_t *offset)
-{
-	struct inode *inode = file_inode(file);
-	struct task_struct *task;
-	unsigned long long val;
-	int ret;
-
-	ret = kstrtoull_from_user(buf, count, 10, &val);
-	if (ret)
-		return ret;
-
-	if (val != 0)
-		return -EINVAL;
-
-	task = get_proc_task(inode);
-	if (!task)
-		return -ESRCH;
-
-	if (!task->dmabuf_info) {
-		pr_err("%s dmabuf accounting record was not allocated\n", __func__);
-		ret = -ENOMEM;
-		goto out;
-	}
-
-	spin_lock(&task->dmabuf_info->lock);
-	task->dmabuf_info->rss_hwm = task->dmabuf_info->rss;
-	spin_unlock(&task->dmabuf_info->lock);
-
-out:
-	put_task_struct(task);
-
-	return ret < 0 ? ret : count;
-}
-
-static const struct file_operations proc_dmabuf_rss_hwm_operations = {
-	.open		= proc_dmabuf_rss_hwm_open,
-	.write		= proc_dmabuf_rss_hwm_write,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-};
 #endif
 
 /*
@@ -3524,7 +3448,6 @@ static const struct pid_entry tgid_base_stuff[] = {
 #endif
 #ifdef CONFIG_DMA_SHARED_BUFFER
 	ONE("dmabuf_rss", S_IRUGO, proc_dmabuf_rss_show),
-	REG("dmabuf_rss_hwm", S_IRUGO|S_IWUSR, proc_dmabuf_rss_hwm_operations),
 #endif
 };
 

include/linux/dma-buf.h

@@ -659,8 +659,8 @@ struct task_dma_buf_record {
 };
 
 /**
- * struct task_dma_buf_info - Holds RSS and RSS HWM counters, and a list of
+ * struct task_dma_buf_info - Holds a RSS counter, and a list of dmabufs for all
- * dmabufs for all tasks that share both mm_struct and files_struct.
+ * tasks that share both mm_struct and files_struct.
  *
  * @rss: The sum of all dmabuf memory referenced by the tasks via memory
  *       mappings or file descriptors in bytes. Buffers referenced more than
@@ -668,15 +668,12 @@ struct task_dma_buf_record {
  *       of both mmaps and FDs) only cause the buffer to be accounted to the
  *       process once. Partial mappings cause the full size of the buffer to be
  *       accounted, regardless of the size of the mapping.
- * @rss_hwm: The maximum value of @rss over the lifetime of this struct. (Unless,
- *           reset by userspace.)
  * @refcnt: The number of tasks sharing this struct.
  * @lock: Lock protecting writes for @rss, and reads/writes for @dmabufs.
  * @dmabufs: List of all dmabufs referenced by the tasks.
  */
 struct task_dma_buf_info {
 	s64 rss;
-	s64 rss_hwm;
 	refcount_t refcnt;
 	spinlock_t lock;
 	struct list_head dmabufs;

kernel/fork.c

@@ -2314,7 +2314,6 @@ static int copy_dmabuf_info(u64 clone_flags, struct task_struct *p)
 	if (current->dmabuf_info) {
 		spin_lock(&current->dmabuf_info->lock);
 		p->dmabuf_info->rss = current->dmabuf_info->rss;
-		p->dmabuf_info->rss_hwm = current->dmabuf_info->rss;
 		list_for_each_entry(rec, &current->dmabuf_info->dmabufs, node) {
 			copy = kmalloc(sizeof(*copy), GFP_KERNEL);
 			if (!copy) {
@@ -2329,7 +2328,6 @@ static int copy_dmabuf_info(u64 clone_flags, struct task_struct *p)
 		spin_unlock(&current->dmabuf_info->lock);
 	} else {
 		p->dmabuf_info->rss = 0;
-		p->dmabuf_info->rss_hwm = 0;
 	}
 
 	return 0;