From: Peter Xu <peterx@redhat.com>
To: David Hildenbrand <david@redhat.com>
Cc: "Sierra Guiza, Alejandro \(Alex\)" <alex.sierra@amd.com>,
Huang Ying <ying.huang@intel.com>,
Ralph Campbell <rcampbell@nvidia.com>,
linuxppc-dev@lists.ozlabs.org, Lyude Paul <lyude@redhat.com>,
Karol Herbst <kherbst@redhat.com>,
Nadav Amit <nadav.amit@gmail.com>,
Felix Kuehling <Felix.Kuehling@amd.com>,
Alistair Popple <apopple@nvidia.com>,
LKML <linux-kernel@vger.kernel.org>,
Matthew Wilcox <willy@infradead.org>,
linux-mm@kvack.org, Logan Gunthorpe <logang@deltatee.com>,
Ben Skeggs <bskeggs@redhat.com>, Jason Gunthorpe <jgg@nvidia.com>,
John Hubbard <jhubbard@nvidia.com>,
stable@vger.kernel.org, akpm@linux-foundation.org,
huang ying <huang.ying.caritas@gmail.com>
Subject: Re: [PATCH v3 2/3] mm/migrate_device.c: Copy pte dirty bit to page
Date: Fri, 26 Aug 2022 11:55:42 -0400 [thread overview]
Message-ID: <Ywjs/i4kIVlxZwpb@xz-m1.local> (raw)
In-Reply-To: <72146725-3d70-0427-50d4-165283a5a85d@redhat.com>
On Fri, Aug 26, 2022 at 04:47:22PM +0200, David Hildenbrand wrote:
> > To me anon exclusive only shows this mm exclusively owns this page. I
> > didn't quickly figure out why that requires different handling on tlb
> > flushs. Did I perhaps miss something?
>
> GUP-fast is the magic bit, we have to make sure that we won't see new
> GUP pins, thus the TLB flush.
>
> include/linux/mm.h:gup_must_unshare() contains documentation.
Hmm.. Shouldn't ptep_get_and_clear() (e.g., xchg() on x86_64) already
guarantees that no other process/thread will see this pte anymore
afterwards?
--
Peter Xu
next prev parent reply other threads:[~2022-08-26 15:56 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-24 3:03 [PATCH v3 1/3] mm/migrate_device.c: Flush TLB while holding PTL Alistair Popple
2022-08-24 3:03 ` [PATCH v3 2/3] mm/migrate_device.c: Copy pte dirty bit to page Alistair Popple
2022-08-24 15:39 ` Peter Xu
2022-08-25 22:21 ` Alistair Popple
2022-08-25 23:27 ` Peter Xu
2022-08-26 1:02 ` Alistair Popple
2022-08-26 1:14 ` Huang, Ying
2022-08-26 14:32 ` Peter Xu
2022-08-26 14:47 ` David Hildenbrand
2022-08-26 15:55 ` Peter Xu [this message]
2022-08-26 16:46 ` David Hildenbrand
2022-08-26 21:37 ` Peter Xu
2022-08-26 22:19 ` David Hildenbrand
2022-08-24 3:03 ` [PATCH v3 3/3] selftests/hmm-tests: Add test for dirty bits Alistair Popple
2022-08-24 8:21 ` [PATCH v3 1/3] mm/migrate_device.c: Flush TLB while holding PTL David Hildenbrand
2022-08-24 12:26 ` Alistair Popple
2022-08-24 12:35 ` David Hildenbrand
2022-08-25 1:36 ` Huang, Ying
2022-08-25 22:35 ` Alistair Popple
2022-08-26 0:56 ` Huang, Ying
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