From: Alistair Popple <apopple@nvidia.com> To: Jason Gunthorpe <jgg@nvidia.com> Cc: Tejun Heo <tj@kernel.org>, Michal Hocko <mhocko@suse.com>, Yosry Ahmed <yosryahmed@google.com>, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, jhubbard@nvidia.com, tjmercier@google.com, hannes@cmpxchg.org, surenb@google.com, mkoutny@suse.com, daniel@ffwll.ch, "Daniel P . Berrange" <berrange@redhat.com>, Alex Williamson <alex.williamson@redhat.com>, Zefan Li <lizefan.x@bytedance.com>, Andrew Morton <akpm@linux-foundation.org> Subject: Re: [PATCH 14/19] mm: Introduce a cgroup for pinned memory Date: Thu, 23 Feb 2023 09:59:35 +1100 [thread overview] Message-ID: <87k009nvnr.fsf@nvidia.com> (raw) In-Reply-To: <Y/YRJNwwvqp7nKKt@nvidia.com> Jason Gunthorpe <jgg@nvidia.com> writes: > On Wed, Feb 22, 2023 at 10:38:25PM +1100, Alistair Popple wrote: >> When a driver unpins a page we scan the pinners list and assign >> ownership to the next driver pinning the page by updating memcg_data and >> removing the vm_account from the list. > > I don't see how this works with just the data structure you outlined?? > Every unique page needs its own list_head in the vm_account, it is > doable just incredibly costly. The idea was every driver already needs to allocate a pages array to pass to pin_user_pages(), and by necessity drivers have to keep a reference to the contents of that in one form or another. So conceptually the equivalent of: struct vm_account { struct list_head possible_pinners; struct mem_cgroup *memcg; struct pages **pages; [...] }; Unpinnig involves finding a new owner by traversing the list of page->memcg_data->possible_pinners and iterating over *pages[] to figure out if that vm_account actually has this page pinned or not and could own it. Agree this is costly though. And I don't think all drivers keep the array around so "iterating over *pages[]" may need to be a callback. > Jason
WARNING: multiple messages have this Message-ID (diff)
From: Alistair Popple <apopple-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> To: Jason Gunthorpe <jgg-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> Cc: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>, Yosry Ahmed <yosryahmed-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, jhubbard-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, tjmercier-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org, surenb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, mkoutny-IBi9RG/b67k@public.gmane.org, daniel-/w4YWyX8dFk@public.gmane.org, "Daniel P . Berrange" <berrange-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Alex Williamson <alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Zefan Li <lizefan.x-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> Subject: Re: [PATCH 14/19] mm: Introduce a cgroup for pinned memory Date: Thu, 23 Feb 2023 09:59:35 +1100 [thread overview] Message-ID: <87k009nvnr.fsf@nvidia.com> (raw) In-Reply-To: <Y/YRJNwwvqp7nKKt-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> Jason Gunthorpe <jgg-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> writes: > On Wed, Feb 22, 2023 at 10:38:25PM +1100, Alistair Popple wrote: >> When a driver unpins a page we scan the pinners list and assign >> ownership to the next driver pinning the page by updating memcg_data and >> removing the vm_account from the list. > > I don't see how this works with just the data structure you outlined?? > Every unique page needs its own list_head in the vm_account, it is > doable just incredibly costly. The idea was every driver already needs to allocate a pages array to pass to pin_user_pages(), and by necessity drivers have to keep a reference to the contents of that in one form or another. So conceptually the equivalent of: struct vm_account { struct list_head possible_pinners; struct mem_cgroup *memcg; struct pages **pages; [...] }; Unpinnig involves finding a new owner by traversing the list of page->memcg_data->possible_pinners and iterating over *pages[] to figure out if that vm_account actually has this page pinned or not and could own it. Agree this is costly though. And I don't think all drivers keep the array around so "iterating over *pages[]" may need to be a callback. > Jason
next prev parent reply other threads:[~2023-02-22 23:11 UTC|newest] Thread overview: 128+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-02-06 7:47 [PATCH 00/19] mm: Introduce a cgroup to limit the amount of locked and pinned memory Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 7:47 ` [PATCH 01/19] mm: Introduce vm_account Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 7:47 ` [PATCH 02/19] drivers/vhost: Convert to use vm_account Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 7:47 ` [PATCH 03/19] drivers/vdpa: Convert vdpa to use the new vm_structure Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 7:47 ` [PATCH 04/19] infiniband/umem: Convert to use vm_account Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 7:47 ` [PATCH 05/19] RMDA/siw: " Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-12 17:32 ` Bernard Metzler 2023-02-06 7:47 ` [PATCH 06/19] RDMA/usnic: convert " Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 7:47 ` [PATCH 07/19] vfio/type1: Charge pinned pages to pinned_vm instead of locked_vm Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 7:47 ` [PATCH 08/19] vfio/spapr_tce: Convert accounting to pinned_vm Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 7:47 ` [PATCH 09/19] io_uring: convert to use vm_account Alistair Popple 2023-02-06 15:29 ` Jens Axboe 2023-02-06 15:29 ` Jens Axboe 2023-02-07 1:03 ` Alistair Popple 2023-02-07 1:03 ` Alistair Popple 2023-02-07 14:28 ` Jens Axboe 2023-02-07 14:55 ` Jason Gunthorpe 2023-02-07 14:55 ` Jason Gunthorpe 2023-02-07 17:05 ` Jens Axboe 2023-02-07 17:05 ` Jens Axboe 2023-02-13 11:30 ` Alistair Popple 2023-02-13 11:30 ` Alistair Popple 2023-02-06 7:47 ` [PATCH 10/19] net: skb: Switch to using vm_account Alistair Popple 2023-02-06 7:47 ` [PATCH 11/19] xdp: convert to use vm_account Alistair Popple 2023-02-06 7:47 ` [PATCH 12/19] kvm/book3s_64_vio: Convert account_locked_vm() to vm_account_pinned() Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 7:47 ` [PATCH 13/19] fpga: dfl: afu: convert to use vm_account Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 7:47 ` [PATCH 14/19] mm: Introduce a cgroup for pinned memory Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 21:01 ` Yosry Ahmed 2023-02-06 21:01 ` Yosry Ahmed 2023-02-06 21:14 ` Tejun Heo 2023-02-06 21:14 ` Tejun Heo 2023-02-06 22:32 ` Yosry Ahmed 2023-02-06 22:32 ` Yosry Ahmed 2023-02-06 22:36 ` Tejun Heo 2023-02-06 22:39 ` Yosry Ahmed 2023-02-06 22:39 ` Yosry Ahmed 2023-02-06 23:25 ` Tejun Heo 2023-02-06 23:25 ` Tejun Heo 2023-02-06 23:34 ` Yosry Ahmed 2023-02-06 23:34 ` Yosry Ahmed 2023-02-06 23:40 ` Jason Gunthorpe 2023-02-06 23:40 ` Jason Gunthorpe 2023-02-07 0:32 ` Tejun Heo 2023-02-07 0:32 ` Tejun Heo 2023-02-07 12:19 ` Jason Gunthorpe 2023-02-07 12:19 ` Jason Gunthorpe 2023-02-15 19:00 ` Michal Hocko 2023-02-15 19:00 ` Michal Hocko 2023-02-15 19:07 ` Jason Gunthorpe 2023-02-15 19:07 ` Jason Gunthorpe 2023-02-16 8:04 ` Michal Hocko 2023-02-16 8:04 ` Michal Hocko 2023-02-16 12:45 ` Jason Gunthorpe 2023-02-16 12:45 ` Jason Gunthorpe 2023-02-21 16:51 ` Tejun Heo 2023-02-21 16:51 ` Tejun Heo 2023-02-21 17:25 ` Jason Gunthorpe 2023-02-21 17:29 ` Tejun Heo 2023-02-21 17:29 ` Tejun Heo 2023-02-21 17:51 ` Jason Gunthorpe 2023-02-21 17:51 ` Jason Gunthorpe 2023-02-21 18:07 ` Tejun Heo 2023-02-21 18:07 ` Tejun Heo 2023-02-21 19:26 ` Jason Gunthorpe 2023-02-21 19:26 ` Jason Gunthorpe 2023-02-21 19:45 ` Tejun Heo 2023-02-21 19:45 ` Tejun Heo 2023-02-21 19:49 ` Tejun Heo 2023-02-21 19:49 ` Tejun Heo 2023-02-21 19:57 ` Jason Gunthorpe 2023-02-22 11:38 ` Alistair Popple 2023-02-22 11:38 ` Alistair Popple 2023-02-22 12:57 ` Jason Gunthorpe 2023-02-22 12:57 ` Jason Gunthorpe 2023-02-22 22:59 ` Alistair Popple [this message] 2023-02-22 22:59 ` Alistair Popple 2023-02-23 0:05 ` Christoph Hellwig 2023-02-23 0:35 ` Alistair Popple 2023-02-23 0:35 ` Alistair Popple 2023-02-23 1:53 ` Jason Gunthorpe 2023-02-23 1:53 ` Jason Gunthorpe 2023-02-23 9:12 ` Daniel P. Berrangé 2023-02-23 17:31 ` Jason Gunthorpe 2023-02-23 17:31 ` Jason Gunthorpe 2023-02-23 17:18 ` T.J. Mercier 2023-02-23 17:28 ` Jason Gunthorpe 2023-02-23 17:28 ` Jason Gunthorpe 2023-02-23 18:03 ` Yosry Ahmed 2023-02-23 18:10 ` Jason Gunthorpe 2023-02-23 18:10 ` Jason Gunthorpe 2023-02-23 18:14 ` Yosry Ahmed 2023-02-23 18:14 ` Yosry Ahmed 2023-02-23 18:15 ` Tejun Heo 2023-02-23 18:17 ` Jason Gunthorpe 2023-02-23 18:17 ` Jason Gunthorpe 2023-02-23 18:22 ` Tejun Heo 2023-02-23 18:22 ` Tejun Heo 2023-02-07 1:00 ` Waiman Long 2023-02-07 1:00 ` Waiman Long 2023-02-07 1:03 ` Tejun Heo 2023-02-07 1:50 ` Alistair Popple 2023-02-07 1:50 ` Alistair Popple 2023-02-06 7:47 ` [PATCH 15/19] mm/util: Extend vm_account to charge pages against the pin cgroup Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 7:47 ` [PATCH 16/19] mm/util: Refactor account_locked_vm Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 7:47 ` [PATCH 17/19] mm: Convert mmap and mlock to use account_locked_vm Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 7:47 ` [PATCH 18/19] mm/mmap: Charge locked memory to pins cgroup Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-06 21:12 ` Yosry Ahmed 2023-02-06 7:47 ` [PATCH 19/19] selftests/vm: Add pins-cgroup selftest for mlock/mmap Alistair Popple 2023-02-06 7:47 ` Alistair Popple 2023-02-16 11:01 ` [PATCH 00/19] mm: Introduce a cgroup to limit the amount of locked and pinned memory David Hildenbrand 2023-02-16 11:01 ` David Hildenbrand
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