From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Shakeel Butt <shakeelb@google.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Yang Shi <shy828301@gmail.com>, Miaohe Lin <linmiaohe@huawei.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Michal Hocko <mhocko@suse.com>, Rik van Riel <riel@surriel.com>,
Christoph Hellwig <hch@infradead.org>,
Matthew Wilcox <willy@infradead.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Alexey Gladkov <legion@kernel.org>,
Chris Wilson <chris@chris-wilson.co.uk>,
Matthew Auld <matthew.auld@intel.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-api@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 08/16] huge tmpfs: fcntl(fd, F_HUGEPAGE) and fcntl(fd, F_NOHUGEPAGE)
Date: Wed, 4 Aug 2021 17:08:05 +0300 [thread overview]
Message-ID: <20210804140805.vpuerwaiqtcvc5or@box.shutemov.name> (raw)
In-Reply-To: <1c32c75b-095-22f0-aee3-30a44d4a4744@google.com>
On Fri, Jul 30, 2021 at 12:48:33AM -0700, Hugh Dickins wrote:
> Add support for fcntl(fd, F_HUGEPAGE) and fcntl(fd, F_NOHUGEPAGE), to
> select hugeness per file: useful to override the default hugeness of the
> shmem mount, when occasionally needing to store a hugepage file in a
> smallpage mount or vice versa.
Hm. But why is the new MFD_* needed if the fcntl() can do the same.
> These fcntls just specify whether or not to try for huge pages when
> allocating to the object later: F_HUGEPAGE does not touch small pages
> already allocated (though khugepaged may do so when the file is mapped
> afterwards), F_NOHUGEPAGE does not split huge pages already allocated.
>
> Why fcntl? Because it's already in use (for sealing) on memfds; and I'm
> anxious to keep this simple, just applying it to whole files: fallocate,
> madvise and posix_fadvise each involve a range, which would need a new
> kind of tree attached to the inode for proper support.
Most of fadvise() operations ignore the range. I like fadvise() because
it's less prescriptive: kernel is free to ignore it.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2021-08-04 14:08 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-30 7:22 [PATCH 00/16] tmpfs: HUGEPAGE and MEM_LOCK fcntls and memfds Hugh Dickins
2021-07-30 7:25 ` [PATCH 01/16] huge tmpfs: fix fallocate(vanilla) advance over huge pages Hugh Dickins
2021-07-30 21:36 ` Yang Shi
2021-08-01 3:38 ` Hugh Dickins
2021-08-02 20:36 ` Yang Shi
2021-07-30 7:28 ` [PATCH 02/16] huge tmpfs: fix split_huge_page() after FALLOC_FL_KEEP_SIZE Hugh Dickins
2021-07-30 23:48 ` Yang Shi
2021-07-30 7:30 ` [PATCH 03/16] huge tmpfs: remove shrinklist addition from shmem_setattr() Hugh Dickins
2021-07-30 21:50 ` Yang Shi
2021-07-30 7:36 ` [PATCH 04/16] huge tmpfs: revert shmem's use of transhuge_vma_enabled() Hugh Dickins
2021-07-30 21:56 ` Yang Shi
2021-08-01 4:01 ` Hugh Dickins
2021-08-02 20:39 ` Yang Shi
2021-07-30 7:39 ` [PATCH 05/16] huge tmpfs: move shmem_huge_enabled() upwards Hugh Dickins
2021-07-30 21:57 ` Yang Shi
2021-07-30 7:42 ` [PATCH 06/16] huge tmpfs: shmem_is_huge(vma, inode, index) Hugh Dickins
2021-07-30 23:34 ` Yang Shi
2021-08-01 5:22 ` Hugh Dickins
2021-08-01 5:37 ` Hugh Dickins
2021-08-02 21:14 ` Yang Shi
2021-08-04 8:28 ` Hugh Dickins
2021-08-04 19:01 ` Yang Shi
2021-08-06 5:21 ` Hugh Dickins
2021-08-06 17:41 ` Yang Shi
2021-08-05 23:04 ` Yang Shi
2021-08-06 5:43 ` Hugh Dickins
2021-08-06 17:57 ` Yang Shi
2021-08-12 18:19 ` Yang Shi
2021-07-30 7:45 ` [PATCH 07/16] memfd: memfd_create(name, MFD_HUGEPAGE) for shmem huge pages Hugh Dickins
2021-08-04 14:03 ` Kirill A. Shutemov
2021-08-06 3:33 ` Hugh Dickins
2021-07-30 7:48 ` [PATCH 08/16] huge tmpfs: fcntl(fd, F_HUGEPAGE) and fcntl(fd, F_NOHUGEPAGE) Hugh Dickins
2021-08-04 14:08 ` Kirill A. Shutemov [this message]
2021-08-06 4:34 ` Hugh Dickins
2021-07-30 7:51 ` [PATCH 09/16] huge tmpfs: decide stat.st_blksize by shmem_is_huge() Hugh Dickins
2021-07-30 23:40 ` Yang Shi
2021-07-30 7:55 ` [PATCH 10/16] tmpfs: fcntl(fd, F_MEM_LOCK) to memlock a tmpfs file Hugh Dickins
2021-08-03 1:38 ` Matthew Wilcox
2021-08-04 9:15 ` Hugh Dickins
2021-07-30 7:57 ` [PATCH 11/16] tmpfs: fcntl(fd, F_MEM_LOCKED) to test if memlocked Hugh Dickins
2021-07-30 8:00 ` [PATCH 12/16] tmpfs: refuse memlock when fallocated beyond i_size Hugh Dickins
2021-07-30 8:03 ` [PATCH 13/16] mm: bool user_shm_lock(loff_t size, struct ucounts *) Hugh Dickins
2021-07-30 8:06 ` [PATCH 14/16] mm: user_shm_lock(,,getuc) and user_shm_unlock(,,putuc) Hugh Dickins
2021-07-30 8:09 ` [PATCH 15/16] tmpfs: permit changing size of memlocked file Hugh Dickins
2021-07-30 8:13 ` [PATCH 16/16] memfd: memfd_create(name, MFD_MEM_LOCK) for memlocked shmem Hugh Dickins
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