From: Andrew Morton <akpm@linux-foundation.org>
To: Stefan Roesch <shr@devkernel.io>
Cc: kernel-team@fb.com, david@redhat.com, hannes@cmpxchg.org,
riel@surriel.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH v3 0/2] mm/ksm: add fork-exec support for prctl
Date: Thu, 21 Sep 2023 17:32:51 -0700 [thread overview]
Message-ID: <20230921173251.54b854fb0ec7af2bf3e3ec3b@linux-foundation.org> (raw)
In-Reply-To: <20230921164709.3627565-1-shr@devkernel.io>
On Thu, 21 Sep 2023 09:47:07 -0700 Stefan Roesch <shr@devkernel.io> wrote:
> A process can enable KSM with the prctl system call. When the process is
> forked the KSM flag is inherited by the child process.
I guess that's logical, as it's still the same program.
> However if the
> process is executing an exec system call directly after the fork, the
> KSM setting is cleared. This patch series addresses this problem.
Well... who said it's a problem? There's nothing in our documentation
about this(?). Why is the current behavior wrong? If the new program
wants KSM, it can turn on KSM.
This significant change in user-visible behavior deserves much more
explanation and justification, please. Including an explanation of why
it's OK to change kernel behavior under existing users' feet like this,
next prev parent reply other threads:[~2023-09-22 0:33 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-21 16:47 Stefan Roesch
2023-09-21 16:47 ` [PATCH v3 1/2] mm/ksm: support fork/exec " Stefan Roesch
2023-09-21 16:47 ` [PATCH v3 2/2] mm/ksm: Test case for prctl fork/exec workflow Stefan Roesch
2023-09-22 0:32 ` Andrew Morton [this message]
2023-09-22 16:08 ` [PATCH v3 0/2] mm/ksm: add fork-exec support for prctl Stefan Roesch
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