Re: [PATCH v3 08/16] memcg: enable accounting of ipc resources

On 4/23/21 3:16 PM, Alexey Dobriyan wrote:

On Thu, Apr 22, 2021 at 01:37:02PM +0300, Vasily Averin wrote:

quoted

When user creates IPC objects it forces kernel to allocate memory for
these long-living objects.

It makes sense to account them to restrict the host's memory consumption
from inside the memcg-limited container.

This patch enables accounting for IPC shared memory segments, messages
semaphores and semaphore's undo lists.

quoted

--- a/ipc/msg.c
+++ b/ipc/msg.c

@@ -147,7 +147,7 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params)
 	key_t key = params->key;
 	int msgflg = params->flg;
 
-	msq = kvmalloc(sizeof(*msq), GFP_KERNEL);
+	msq = kvmalloc(sizeof(*msq), GFP_KERNEL_ACCOUNT);

Why this requires vmalloc? struct msg_queue is not big at all.

quoted

--- a/ipc/shm.c
+++ b/ipc/shm.c

@@ -619,7 +619,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 			ns->shm_tot + numpages > ns->shm_ctlall)
 		return -ENOSPC;
 
-	shp = kvmalloc(sizeof(*shp), GFP_KERNEL);
+	shp = kvmalloc(sizeof(*shp), GFP_KERNEL_ACCOUNT);

Same question.
Kmem caches can be GFP_ACCOUNT by default.

It is side effect: previously all these objects was allocated via ipc_alloc/ipc_alloc_rcu
function called kvmalloc inside.

Should I replace it to kmalloc right in this patch?

Thank you,
	Vasily Averin