On Mon, Apr 16, 2018 at 1:51 PM, Shakeel Butt <shakeelb@xxxxxxxxxx> wrote: > Introduce the memcg variant for kmalloc[_node] and > kmem_cache_alloc[_node]. For kmem_cache_alloc, the kernel switches the > root kmem cache with the memcg specific kmem cache for __GFP_ACCOUNT > allocations to charge those allocations to the memcg. However, the memcg > to charge is extracted from the current task_struct. This patch > introduces the variant of kmem cache allocation functions where the memcg > can be provided explicitly by the caller instead of deducing the memcg > from the current task. > > The kmalloc allocations are underlying served using the kmem caches unless > the size of the allocation request is larger than KMALLOC_MAX_CACHE_SIZE, > in which case, the kmem caches are bypassed and the request is routed > directly to page allocator. So, for __GFP_ACCOUNT kmalloc allocations, > the memcg of current task is charged. This patch introduces memcg variant > of kmalloc functions to allow callers to provide memcg for charging. > > These functions are useful for use-cases where the allocations should be > charged to the memcg different from the memcg of the caller. One such > concrete use-case is the allocations for fsnotify event objects where the > objects should be charged to the listener instead of the producer. > > One requirement to call these functions is that the caller must have the > reference to the memcg. Using kmalloc_memcg and kmem_cache_alloc_memcg > implicitly assumes that the caller is requesting a __GFP_ACCOUNT > allocation. > > Signed-off-by: Shakeel Butt <shakeelb@xxxxxxxxxx> I will send the v6 of this patchset after this merge window. In v6, I will make memalloc_memcg_[save|restore] scope API similar to NOFS, NOIO and NORECLAIM APIs. > --- > Changelog since v4: > - Removed branch from hot path of memory charging. > > Changelog since v3: > - Added node variant of directed kmem allocation functions. > > Changelog since v2: > - Merge the kmalloc_memcg patch into this patch. > - Instead of plumbing memcg throughout, use field in task_struct to pass > the target_memcg. > > Changelog since v1: > - Fixed build for SLOB >
