quoted

quoted

@@ -678,13 +675,11 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,

A  A  A  }

A  A  A  /* charge against new page */
- A  A  charge = mem_cgroup_prepare_migration(page, newpage, &mem, GFP_KERNEL);
- A  A  if (charge == -ENOMEM) {
- A  A  A  A  A  A  rc = -ENOMEM;
+ A  A  rc = mem_cgroup_prepare_migration(page, newpage, &mem, GFP_KERNEL);
+ A  A  if (rc)
A  A  A  A  A  A  A  goto unlock;
- A  A  }
- A  A  BUG_ON(charge);

+ A  A  rc = -EAGAIN;
A  A  A  if (PageWriteback(page)) {
A  A  A  A  A  A  A  if (!force || !sync)
A  A  A  A  A  A  A  A  A  A  A  goto uncharge;

How about

A  A  A  A if (mem_cgroup_prepare_migration(..)) {
A  A  A  A  A  A  A  A rc = -ENOMEM;
A  A  A  A  A  A  A  A goto unlock;
A  A  A  A }

?

Re-setting "rc" to -EAGAIN is not necessary in this case.
"if (mem_cgroup_...)" is commonly used in many places.

It works now but Johannes doesn't like it and me, either.
It makes unnecessary dependency which mem_cgroup_preparre_migration
can't propagate error to migrate_pages.
Although we don't need it, I want to remove such unnecessary dependency.

I see.
Thank you for your explanation.

Daisuke Nishimura.

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