Add a parameter to enable dma-buf heaps allocation accounting using cgroup for heaps that implement it. It is disabled by default as doing so incurs caveats based on how memcg currently accounts for shared buffers.

Signed-off-by: Eric Chanudet echanude@redhat.com --- drivers/dma-buf/dma-heap.c | 5 +++++ include/linux/dma-heap.h | 2 ++ 2 files changed, 7 insertions(+)

diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c index 8ab49924f8b71a0272dc89a609539a429feaf6c8..d230ddeb24e0fa1f2d51cb5d2868ec54fc8376a8 100644 --- a/drivers/dma-buf/dma-heap.c +++ b/drivers/dma-buf/dma-heap.c @@ -49,6 +49,11 @@ static dev_t dma_heap_devt; static struct class *dma_heap_class; static DEFINE_XARRAY_ALLOC(dma_heap_minors);

+bool __read_mostly mem_accounting; +module_param(mem_accounting, bool, 0444); +MODULE_PARM_DESC(mem_accounting, + "Enable cgroup-based memory accounting for dma-buf heap allocations (default=false)."); + static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len, u32 fd_flags, u64 heap_flags) diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h index 27d15f60950a2093e592be1b961c02e672826e58..648328a64b27eaf25c8b18809a02c6410cbbffde 100644 --- a/include/linux/dma-heap.h +++ b/include/linux/dma-heap.h @@ -46,4 +46,6 @@ const char *dma_heap_get_name(struct dma_heap *heap);

struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info);

+extern bool mem_accounting; + #endif /* _DMA_HEAPS_H */

The system dma-buf heap lets userspace allocate buffers from the page allocator. However, these allocations are not accounted for in memcg, allowing processes to escape limits that may be configured.

Pass __GFP_ACCOUNT for system heap allocations, based on the dma_heap.mem_accounting parameter, to use memcg and account for them.

Signed-off-by: Eric Chanudet echanude@redhat.com --- drivers/dma-buf/heaps/system_heap.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c index 4c782fe33fd497a74eb5065797259576f9b651b6..4049d042afa14ec2f4d034f59f1740600a20c1e5 100644 --- a/drivers/dma-buf/heaps/system_heap.c +++ b/drivers/dma-buf/heaps/system_heap.c @@ -320,14 +320,17 @@ static struct page *alloc_largest_available(unsigned long size, { struct page *page; int i; + gfp_t flags;

for (i = 0; i < NUM_ORDERS; i++) { if (size < (PAGE_SIZE << orders[i])) continue; if (max_order < orders[i]) continue; - - page = alloc_pages(order_flags[i], orders[i]); + flags = order_flags[i]; + if (mem_accounting) + flags |= __GFP_ACCOUNT; + page = alloc_pages(flags, orders[i]); if (!page) continue; return page;