On 6/12/2020 8:19 AM, Jens Axboe wrote:
On 6/12/20 9:16 AM, Jens Axboe wrote:
On 6/11/20 8:23 PM, Bijan Mottahedeh wrote:
Long term, it makes sense to separate reporting and enforcing of pinned
memory usage.
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@xxxxxxxxxx>
It is useful to view
---
fs/io_uring.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 4248726..cf3acaa 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7080,6 +7080,8 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx,
static void io_unaccount_mem(struct user_struct *user, unsigned long nr_pages)
{
atomic_long_sub(nr_pages, &user->locked_vm);
+ if (current->mm)
+ atomic_long_sub(nr_pages, ¤t->mm->pinned_vm);
}
static int io_account_mem(struct user_struct *user, unsigned long nr_pages)
@@ -7096,6 +7098,8 @@ static int io_account_mem(struct user_struct *user, unsigned long nr_pages)
return -ENOMEM;
} while (atomic_long_cmpxchg(&user->locked_vm, cur_pages,
new_pages) != cur_pages);
+ if (current->mm)
+ atomic_long_add(nr_pages, ¤t->mm->pinned_vm);
return 0;
}
current->mm should always be valid for these, so I think you can skip the
checking of that and just make it unconditional.
Two other issues with this:
- It's an atomic64, so seems more appropriate to use the atomic64 helpers
for this one.
- The unaccount could potentially be a different mm, if the ring is shared
and one task sets it up while another tears it down. So we'd need something
to ensure consistency here.
Are you referring to a case where one process creates a ring and sends
the ring fd to another process?
