On Mon, Jan 25, 2021 at 09:18:04AM -0800, Shakeel Butt wrote: > On Mon, Jan 25, 2021 at 8:20 AM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > > > On Thu, Jan 21, 2021 at 02:27:20PM +0200, Mike Rapoport wrote: > > > From: Mike Rapoport <rppt@xxxxxxxxxxxxx> > > > > > > Account memory consumed by secretmem to memcg. The accounting is updated > > > when the memory is actually allocated and freed. I though about doing per-page accounting, but then one would be able to create a lot of secretmem file descriptors, use only a page from each while actual memory consumption will be way higher. > > I think this is wrong. It fails to account subsequent allocators from > > the same PMD. If you want to track like this, you need separate pools > > per memcg. > > > > Are these secretmem pools shared between different jobs/memcgs? A secretmem pool is per anonymous file descriptor and this file descriptor can be shared only explicitly between several processes. So, the secretmem pool should not be shared between different jobs/memcg. Of course, it's possible to spread threads of a process across different memcgs, but in that case the accounting will be similar to what's happening today with sl*b. The first thread to cause kmalloc() will be charged for the allocation of the entire slab and subsequent allocations from that slab will not be accounted. That said, having a pool per memcg will add ton of complexity with very dubious value. -- Sincerely yours, Mike.
