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t=1789570089; bh=nRqwql2BGBgUg07i+72w0ggBRElWDeq7lDyHdnUO4T8=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=T7dUka4qR1knSUCYclelAUpkpvYpsoovJAQnKd5Tw2PiCwpjbdXXUiGYAiUD9MZ+5 8xsaCKEZI+MF8oooxybgsGVjvLgqKgfMJ8TDdCEYRmGqPkvZPMlSfDSi+JJ14rIK1B SDrnoeLUUlOjUMm4xGH4+pjVphbUnO7PY05aw7M7z3bVK32w7JcSRP/CbVyhFRVA9Y lrZtKz5uodD2fpfrnd7cDJ6vsB4QaZQ/9Nt3UayY+v9s5sdRqvI+bPBp3RKK4O69Kj eAPjuEOaQB0XxyxBZO2BTcOsBn/0X0u6HbVBgeRCzC4Nn6kzNsfzF8n2ZPlZKI55v8 fSwn5i38fYsJw== Message-ID: <5437871c-d9ee-49d2-b24f-965c73c29c3e@kernel.org> Date: Wed, 16 Sep 2026 16:48:04 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm/madvise: reclaim isolated folios if PTE restart fails To: Gregory Price , "Lorenzo Stoakes (ARM)" Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, akpm@linux-foundation.org, liam@infradead.org, vbabka@kernel.org, jannh@google.com, wangjiexun@tinylab.org, sashiko-bot , stable@vger.kernel.org References: <20260912110832.3203902-1-gourry@gourry.net> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 3160B180011 X-Rspam-User: X-Stat-Signature: ofqtokyyxq8jogc3wj4kfemptxxj45ig X-HE-Tag: 1789570090-236520 X-HE-Meta: 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 GthKLiZY jlE1je0+DkPAeZrR1UFBDeQwMUgWbtTHy9ofL1FymG4Dh1n2MvWqBE/Lk5l38WwtNowP4pI5s2PI8Hg5Ik9I2XrYzwHMCGfvKFi3dwbpcYzl1LXeaq+7vIm+6o9EPbYary7slJGhpN1+5ilTmyVWlAFohD2/dLu+7zFd3uZqmpspaG65enVKcfjRqP4bBubGwk1lAOPPnt4PSdYB1I4Frna0nl0WOy+kyuvt1i3ZSh0LsJDRIzYxS+oz6nRRBwc2IRPUU Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/16/26 16:42, Gregory Price wrote: > On Wed, Sep 16, 2026 at 03:12:53PM +0100, Lorenzo Stoakes (ARM) wrote: >>> >>> Going to spend a little more time testing and tweaking before I post it. >>> >>> I've been working on a making more extensive unit tests for certain >>> parts of mm/ and this might be a good time to look at whether I can >>> introduce a piece of it. >> >> Nice, curious as to how? >> >> Have you tried the userland VMA tests btw? Not tooting my own horn so to >> speak :P but it's nice, though it comes at a bit of a cost in how the files >> have to be set up... >> > > Yes, in fact I used that as a start for exploring how I might make other > components testable the same way. > > "Stubs... stubs everywhere" > > There's basically 4 testing mechanisms i explored: > > 1) selftest > 2) Usermode Linux (UML) > 3) Userland stuff like VMA > 4) Linux Test Project (for syscall and ABI testing) > > selftests are really limited and actually create a maintenance burden, > they're not real unit tests and are highly dependent on the actual > machine configuration which is super annoying. > > But, lets take the page allocator as an example. > > The only piece of the page allocator that "should" (cough, simplifying > here a bit) be machine specific is zone and node configurations... but > I'm not convinced that this should require a full VM to unit-test. I told Brendan exactly that (try stubbing it) and he tried ... and had to give up at some point because it just wasn't feasible. ;) -- Cheers, David