From: Peter Xu <peterx@redhat.com>
To: Axel Rasmussen <axelrasmussen@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
Andrea Arcangeli <aarcange@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
Jerome Glisse <jglisse@redhat.com>, Joe Perches <joe@perches.com>,
Lokesh Gidra <lokeshgidra@google.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>, Shaohua Li <shli@fb.com>,
Shuah Khan <shuah@kernel.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Wang Qing <wangqing@vivo.com>,
linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-mm@kvack.org, Brian Geffon <bgeffon@google.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
Mina Almasry <almasrymina@google.com>,
Oliver Upton <oupton@google.com>
Subject: Re: [PATCH v6 06/10] userfaultfd/shmem: modify shmem_mfill_atomic_pte to use install_pte()
Date: Tue, 4 May 2021 21:32:04 -0400 [thread overview]
Message-ID: <YJH1lCx9IGqHG+yq@t490s> (raw)
In-Reply-To: <20210503180737.2487560-7-axelrasmussen@google.com>
Axel,
On Mon, May 03, 2021 at 11:07:33AM -0700, Axel Rasmussen wrote:
> In a previous commit, we added the mfill_atomic_install_pte() helper.
> This helper does the job of setting up PTEs for an existing page, to map
> it into a given VMA. It deals with both the anon and shmem cases, as
> well as the shared and private cases.
>
> In other words, shmem_mfill_atomic_pte() duplicates a case it already
> handles. So, expose it, and let shmem_mfill_atomic_pte() use it
> directly, to reduce code duplication.
>
> This requires that we refactor shmem_mfill_atomic_pte() a bit:
>
> Instead of doing accounting (shmem_recalc_inode() et al) part-way
> through the PTE setup, do it afterward. This frees up
> mfill_atomic_install_pte() from having to care about this accounting,
> and means we don't need to e.g. shmem_uncharge() in the error path.
>
> A side effect is this switches shmem_mfill_atomic_pte() to use
> lru_cache_add_inactive_or_unevictable() instead of just lru_cache_add().
> This wrapper does some extra accounting in an exceptional case, if
> appropriate, so it's actually the more correct thing to use.
>
> Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
(The moving of "ret = -ENOMEM" seems unnecessary, but not a big deal I think)
Reviewed-by: Peter Xu <peterx@redhat.com>
Thanks,
--
Peter Xu
next prev parent reply other threads:[~2021-05-05 1:32 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-03 18:07 [PATCH v6 00/10] userfaultfd: add minor fault handling for shmem Axel Rasmussen
2021-05-03 18:07 ` [PATCH v6 01/10] userfaultfd/hugetlbfs: avoid including userfaultfd_k.h in hugetlb.h Axel Rasmussen
2021-05-03 18:07 ` [PATCH v6 02/10] userfaultfd/shmem: combine shmem_{mcopy_atomic,mfill_zeropage}_pte Axel Rasmussen
2021-05-03 18:07 ` [PATCH v6 03/10] userfaultfd/shmem: support minor fault registration for shmem Axel Rasmussen
2021-05-03 18:07 ` [PATCH v6 04/10] userfaultfd/shmem: support UFFDIO_CONTINUE " Axel Rasmussen
2021-05-03 18:07 ` [PATCH v6 05/10] userfaultfd/shmem: advertise shmem minor fault support Axel Rasmussen
2021-05-03 18:07 ` [PATCH v6 06/10] userfaultfd/shmem: modify shmem_mfill_atomic_pte to use install_pte() Axel Rasmussen
2021-05-05 1:32 ` Peter Xu [this message]
2021-05-06 21:12 ` Hugh Dickins
2021-05-03 18:07 ` [PATCH v6 07/10] userfaultfd/selftests: use memfd_create for shmem test type Axel Rasmussen
2021-05-03 18:07 ` [PATCH v6 08/10] userfaultfd/selftests: create alias mappings in the shmem test Axel Rasmussen
2021-05-03 18:07 ` [PATCH v6 09/10] userfaultfd/selftests: reinitialize test context in each test Axel Rasmussen
2021-05-03 18:07 ` [PATCH v6 10/10] userfaultfd/selftests: exercise minor fault handling shmem support Axel Rasmussen
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