From: Alistair Popple <apopple@nvidia.com>
To: Bernard Metzler <BMT@zurich.ibm.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"cgroups@vger.kernel.org" <cgroups@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"jhubbard@nvidia.com" <jhubbard@nvidia.com>,
"tjmercier@google.com" <tjmercier@google.com>,
"hannes@cmpxchg.org" <hannes@cmpxchg.org>,
"surenb@google.com" <surenb@google.com>,
"mkoutny@suse.com" <mkoutny@suse.com>,
"daniel@ffwll.ch" <daniel@ffwll.ch>,
Leon Romanovsky <leon@kernel.org>,
"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
Subject: Re: [RFC PATCH 05/19] RMDA/siw: Convert to use vm_account
Date: Mon, 30 Jan 2023 22:34:50 +1100 [thread overview]
Message-ID: <87lelkz23e.fsf@nvidia.com> (raw)
In-Reply-To: <SA0PR15MB3919F0CCF1D878DE8B243B0199C99@SA0PR15MB3919.namprd15.prod.outlook.com>
Bernard Metzler <BMT@zurich.ibm.com> writes:
>> -----Original Message-----
>> From: Jason Gunthorpe <jgg@nvidia.com>
>> Sent: Tuesday, 24 January 2023 15:37
>> To: Alistair Popple <apopple@nvidia.com>
>> Cc: 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;
>> Bernard Metzler <BMT@zurich.ibm.com>; Leon Romanovsky <leon@kernel.org>;
>> linux-rdma@vger.kernel.org
>> Subject: [EXTERNAL] Re: [RFC PATCH 05/19] RMDA/siw: Convert to use
>> vm_account
>>
>> On Tue, Jan 24, 2023 at 04:42:34PM +1100, Alistair Popple wrote:
>>
>> > @@ -385,20 +382,16 @@ struct siw_umem *siw_umem_get(u64 start, u64 len,
>> bool writable)
>> > if (!umem)
>> > return ERR_PTR(-ENOMEM);
>> >
>> > - mm_s = current->mm;
>> > - umem->owning_mm = mm_s;
>> > umem->writable = writable;
>> >
>> > - mmgrab(mm_s);
>> > + vm_account_init_current(&umem->vm_account);
>> >
>> > if (writable)
>> > foll_flags |= FOLL_WRITE;
>> >
>> > - mmap_read_lock(mm_s);
>> > + mmap_read_lock(current->mm);
>> >
>> > - mlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
>> > -
>> > - if (num_pages + atomic64_read(&mm_s->pinned_vm) > mlock_limit) {
>> > + if (vm_account_pinned(&umem->vm_account, num_pages)) {
>> > rv = -ENOMEM;
>> > goto out_sem_up;
>> > }
>> > @@ -429,7 +422,6 @@ struct siw_umem *siw_umem_get(u64 start, u64 len,
>> bool writable)
>> > goto out_sem_up;
>> >
>> > umem->num_pages += rv;
>> > - atomic64_add(rv, &mm_s->pinned_vm);
>>
>> Also fixes the race bug
>
> But introduces another one. In that loop, umem->num_pages keeps the
> number of pages currently pinned, not the target number. The current
> patch uses that umem->num_pages to call vm_unaccount_pinned() in
> siw_umem_release(). Bailing out before all pages are pinned would
> mess up that accounting during release. Maybe introduce another
> parameter to siw_umem_release(), or better have another umem member
> 'umem->num_pages_accounted' for correct accounting during release.
Yes, I see the problem thanks for pointing it out. Will fix for the next
version.
> Bernard.
>>
>> Jason
next prev parent reply other threads:[~2023-01-30 11:36 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-24 5:42 [RFC PATCH 00/19] mm: Introduce a cgroup to limit the amount of locked and pinned memory Alistair Popple
2023-01-24 5:42 ` [RFC PATCH 01/19] mm: Introduce vm_account Alistair Popple
2023-01-24 6:29 ` Christoph Hellwig
2023-01-24 14:32 ` Jason Gunthorpe
2023-01-30 11:36 ` Alistair Popple
2023-01-31 14:00 ` David Hildenbrand
2023-01-24 5:42 ` [RFC PATCH 02/19] drivers/vhost: Convert to use vm_account Alistair Popple
2023-01-24 5:55 ` Michael S. Tsirkin
2023-01-30 10:43 ` Alistair Popple
2023-01-24 14:34 ` Jason Gunthorpe
2023-01-24 5:42 ` [RFC PATCH 03/19] drivers/vdpa: Convert vdpa to use the new vm_structure Alistair Popple
2023-01-24 14:35 ` Jason Gunthorpe
2023-01-24 5:42 ` [RFC PATCH 04/19] infiniband/umem: Convert to use vm_account Alistair Popple
2023-01-24 5:42 ` [RFC PATCH 05/19] RMDA/siw: " Alistair Popple
2023-01-24 14:37 ` Jason Gunthorpe
2023-01-24 15:22 ` Bernard Metzler
2023-01-24 15:56 ` Bernard Metzler
2023-01-30 11:34 ` Alistair Popple [this message]
2023-01-30 13:27 ` Bernard Metzler
2023-01-24 5:42 ` [RFC PATCH 06/19] RDMA/usnic: convert " Alistair Popple
2023-01-24 14:41 ` Jason Gunthorpe
2023-01-30 11:10 ` Alistair Popple
2023-01-24 5:42 ` [RFC PATCH 07/19] vfio/type1: Charge pinned pages to pinned_vm instead of locked_vm Alistair Popple
2023-01-24 5:42 ` [RFC PATCH 08/19] vfio/spapr_tce: Convert accounting to pinned_vm Alistair Popple
2023-01-24 5:42 ` [RFC PATCH 09/19] io_uring: convert to use vm_account Alistair Popple
2023-01-24 14:44 ` Jason Gunthorpe
2023-01-30 11:12 ` Alistair Popple
2023-01-30 13:21 ` Jason Gunthorpe
2023-01-24 5:42 ` [RFC PATCH 10/19] net: skb: Switch to using vm_account Alistair Popple
2023-01-24 14:51 ` Jason Gunthorpe
2023-01-30 11:17 ` Alistair Popple
2023-02-06 4:36 ` Alistair Popple
2023-02-06 13:14 ` Jason Gunthorpe
2023-01-24 5:42 ` [RFC PATCH 11/19] xdp: convert to use vm_account Alistair Popple
2023-01-24 5:42 ` [RFC PATCH 12/19] kvm/book3s_64_vio: Convert account_locked_vm() to vm_account_pinned() Alistair Popple
2023-01-24 5:42 ` [RFC PATCH 13/19] fpga: dfl: afu: convert to use vm_account Alistair Popple
2023-01-24 5:42 ` [RFC PATCH 14/19] mm: Introduce a cgroup for pinned memory Alistair Popple
2023-01-27 21:44 ` Tejun Heo
2023-01-30 13:20 ` Jason Gunthorpe
2023-01-24 5:42 ` [RFC PATCH 15/19] mm/util: Extend vm_account to charge pages against the pin cgroup Alistair Popple
2023-01-24 5:42 ` [RFC PATCH 16/19] mm/util: Refactor account_locked_vm Alistair Popple
2023-01-24 5:42 ` [RFC PATCH 17/19] mm: Convert mmap and mlock to use account_locked_vm Alistair Popple
2023-01-24 5:42 ` [RFC PATCH 18/19] mm/mmap: Charge locked memory to pins cgroup Alistair Popple
2023-01-24 5:42 ` [RFC PATCH 19/19] selftests/vm: Add pins-cgroup selftest for mlock/mmap Alistair Popple
2023-01-24 18:26 ` [RFC PATCH 00/19] mm: Introduce a cgroup to limit the amount of locked and pinned memory Yosry Ahmed
2023-01-31 0:54 ` Alistair Popple
2023-01-31 5:14 ` Yosry Ahmed
2023-01-31 11:22 ` Alistair Popple
2023-01-31 19:49 ` Yosry Ahmed
2023-01-24 20:12 ` Jason Gunthorpe
2023-01-31 13:57 ` David Hildenbrand
2023-01-31 14:03 ` Jason Gunthorpe
2023-01-31 14:06 ` David Hildenbrand
2023-01-31 14:10 ` Jason Gunthorpe
2023-01-31 14:15 ` David Hildenbrand
2023-01-31 14:21 ` Jason Gunthorpe
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