From: Oscar Salvador <osalvador@suse.de>
To: Jann Horn <jannh@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Muchun Song <muchun.song@linux.dev>,
linux-mm@kvack.org, Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Subject: Re: [PATCH] hugetlb: block hugetlb file creation if hugetlb is not set up
Date: Tue, 3 Jun 2025 07:43:16 +0200 [thread overview]
Message-ID: <aD6LdFTs9j0uhBSU@localhost.localdomain> (raw)
In-Reply-To: <CAG48ez0fQ5Ukg=0Scsv=N2k2jS=YRQpxLFeQRwMREABUr6yrgQ@mail.gmail.com>
On Tue, Jun 03, 2025 at 06:29:24AM +0200, Jann Horn wrote:
> Yes, this change changes kernel behavior that is userspace-visible,
> and causes syscalls to return errors where they worked before.
Yes, that is what make me unease about this.
It is true that most of the hugetlb cases out there work on
pre-allocated pages, because the later it gets the harder to get large
pages from the system.
But as you say below, there might be applications out there that tweak
the sys knobs themselves, and with this change those might break.
Now, how valid are those? Heh, hard to anwser.
So I guess it boils down to how hard and effective is to actually exploit
whatever we manage to create by allowing this.
But if we take that route, I think that hinting the user about this behaviour
change is the right thing to do.
--
Oscar Salvador
SUSE Labs
next prev parent reply other threads:[~2025-06-03 5:43 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-28 17:51 [PATCH] hugetlb: block hugetlb file creation if hugetlb is not set up Jann Horn
2025-06-03 3:41 ` Andrew Morton
2025-06-03 4:29 ` Jann Horn
2025-06-03 5:43 ` Oscar Salvador [this message]
2025-06-03 19:14 ` Jann Horn
2025-06-04 2:54 ` Andrew Morton
2025-06-16 22:09 ` Mark Brown
2025-06-17 9:13 ` David Hildenbrand
2025-06-17 15:35 ` Jann Horn
2025-06-17 8:12 ` kernel test robot
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