[PATCH 6.18.y 05/11] 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: 6.18 uses kvmalloc() + struct_size_t() rather than
kvmalloc_flex()]
---
 io_uring/rsrc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 8d28c6bfebb1..41e5755bd9aa 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -110,9 +110,9 @@ static struct io_mapped_ubuf *io_alloc_imu(struct io_ring_ctx *ctx,
 					   int nr_bvecs)
 {
 	if (nr_bvecs <= IO_CACHED_BVECS_SEGS)
-		return io_cache_alloc(&ctx->imu_cache, GFP_KERNEL);
+		return io_cache_alloc(&ctx->imu_cache, GFP_KERNEL_ACCOUNT);
 	return kvmalloc(struct_size_t(struct io_mapped_ubuf, bvec, nr_bvecs),
-			GFP_KERNEL);
+			GFP_KERNEL_ACCOUNT);
 }
 
 static void io_free_imu(struct io_ring_ctx *ctx, struct io_mapped_ubuf *imu)
@@ -140,7 +140,7 @@ struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx, int type)
 {
 	struct io_rsrc_node *node;
 
-	node = io_cache_alloc(&ctx->node_cache, GFP_KERNEL);
+	node = io_cache_alloc(&ctx->node_cache, GFP_KERNEL_ACCOUNT);
 	if (node) {
 		node->type = type;
 		node->refs = 1;
-- 
2.56.0