[PATCH 6.6.y 4/8] io_uring/rsrc: charge buffer arrays and nodes to memcg

[Jens Axboe <axboe@kernel.dk>]

From: Chris Mason <mason@kernel.org>

Commit 075d5837bafc317e796548f721b8fbf7add6821d upstream.

The io_mapped_ubuf of a registered buffer has one bio_vec per page,
unless the pages coalesce into huge pages. Huge pages only count against
RLIMIT_MEMLOCK once per ring, so a buffer that maps the same 2MB folio
over and over in a way that defeats coalescing gets a full bvec array
per registration while only the one folio counts as locked. 1GB of that
registered in 100 slots took several times a 64MB memory.max, with 2.6MB
charged.

Allocate the io_mapped_ubuf and the io_rsrc_node with
GFP_KERNEL_ACCOUNT. An object reused from the ring caches stays charged
to whoever allocated it first, same as the io_kiocb cache.

Fixes: de2939388be5 ("io_uring: improve registered buffer accounting for huge pages")
Signed-off-by: Chris Mason <mason@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[axboe: 6.6 predates the rsrc node rework, charge the imu kvmalloc() and
the node kzalloc() instead]
---
 io_uring/rsrc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index f0353e8707d5..f35ae7d6ecc7 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -203,7 +203,7 @@ struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
 	if (entry) {
 		ref_node = container_of(entry, struct io_rsrc_node, cache);
 	} else {
-		ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
+		ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL_ACCOUNT);
 		if (!ref_node)
 			return NULL;
 	}
@@ -923,7 +923,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
 		}
 	}
 
-	imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
+	imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL_ACCOUNT);
 	if (!imu)
 		goto done;
 
-- 
2.56.0