From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
To: "Torvalds, Linus" <torvalds@linux-foundation.org>,
"npiggin@gmail.com" <npiggin@gmail.com>
Cc: "songliubraving@fb.com" <songliubraving@fb.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"daniel@iogearbox.net" <daniel@iogearbox.net>,
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"hch@infradead.org" <hch@infradead.org>,
"ast@kernel.org" <ast@kernel.org>,
"Kernel-team@fb.com" <Kernel-team@fb.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"rppt@kernel.org" <rppt@kernel.org>,
"song@kernel.org" <song@kernel.org>,
"pmladek@suse.com" <pmladek@suse.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"hpa@zytor.com" <hpa@zytor.com>,
"dborkman@redhat.com" <dborkman@redhat.com>,
"edumazet@google.com" <edumazet@google.com>,
"bp@alien8.de" <bp@alien8.de>,
"mcgrof@kernel.org" <mcgrof@kernel.org>,
"mbenes@suse.cz" <mbenes@suse.cz>,
"imbrenda@linux.ibm.com" <imbrenda@linux.ibm.com>
Subject: Re: [PATCH v4 bpf 0/4] vmalloc: bpf: introduce VM_ALLOW_HUGE_VMAP
Date: Thu, 21 Apr 2022 15:47:21 +0000 [thread overview]
Message-ID: <25437eade8b2ecf52ff9666a7de9e36928b7d28f.camel@intel.com> (raw)
In-Reply-To: <1650530694.evuxjgtju7.astroid@bobo.none>
On Thu, 2022-04-21 at 18:57 +1000, Nicholas Piggin wrote:
> Those were (AFAIKS) all in arch code though. The patch was the
> fundamental issue for x86 because it had bugs.
This wasn't root caused to arch code:
"BUG: Bad page state in process systemd-udevd"
https://lore.kernel.org/all/14444103-d51b-0fb3-ee63-c3f182f0b546@molgen.mpg.de/
In fact it wasn't root caused at all. But on the surface it seemed like
it didn't have to do with virtual page size assumptions. I wonder if it
might have to do with the vmalloc huge pages using compound pages, then
some caller doing vmalloc_to_page() and getting surprised with what
they could get away with in the struct page. But, regardless there was
an assumption, not proven, that there was some lurking cross-arch issue
that could show up for any vmalloc huge page user.
There is another good reason to opt-in to the current vmalloc huge page
size implementation - vmalloc will round up to huge page size once the
size exceeds the huge page size. Only the callers can know if the
allocation is worth using extra memory for.
next prev parent reply other threads:[~2022-04-21 15:47 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20220415164413.2727220-1-song@kernel.org>
[not found] ` <20220415164413.2727220-2-song@kernel.org>
2022-04-15 17:43 ` [PATCH v4 bpf 1/4] vmalloc: replace VM_NO_HUGE_VMAP with VM_ALLOW_HUGE_VMAP Rik van Riel
[not found] ` <20220415164413.2727220-3-song@kernel.org>
2022-04-15 17:43 ` [PATCH v4 bpf 2/4] page_alloc: use vmalloc_huge for large system hash Rik van Riel
2022-04-25 7:07 ` Geert Uytterhoeven
2022-04-25 8:17 ` Linus Torvalds
2022-04-25 8:24 ` Geert Uytterhoeven
[not found] ` <20220415164413.2727220-4-song@kernel.org>
2022-04-15 18:06 ` [PATCH v4 bpf 3/4] module: introduce module_alloc_huge Rik van Riel
2022-06-16 16:10 ` Dave Hansen
2022-04-15 19:05 ` [PATCH v4 bpf 0/4] vmalloc: bpf: introduce VM_ALLOW_HUGE_VMAP Luis Chamberlain
2022-04-16 1:34 ` Song Liu
2022-04-16 1:42 ` Luis Chamberlain
2022-04-16 1:43 ` Luis Chamberlain
2022-04-16 5:08 ` Christoph Hellwig
2022-04-16 19:55 ` Song Liu
2022-04-16 20:30 ` Linus Torvalds
2022-04-16 22:26 ` Song Liu
2022-04-18 10:06 ` Mike Rapoport
2022-04-19 0:44 ` Luis Chamberlain
2022-04-19 1:56 ` Edgecombe, Rick P
2022-04-19 5:36 ` Song Liu
2022-04-19 18:42 ` Mike Rapoport
2022-04-19 19:20 ` Linus Torvalds
2022-04-20 2:03 ` Alexei Starovoitov
2022-04-20 2:18 ` Linus Torvalds
2022-04-20 14:42 ` Song Liu
2022-04-20 18:28 ` Luis Chamberlain
2022-04-21 3:25 ` Nicholas Piggin
2022-04-21 5:48 ` Linus Torvalds
2022-04-21 6:02 ` Linus Torvalds
2022-04-21 9:07 ` Nicholas Piggin
2022-04-21 8:57 ` Nicholas Piggin
2022-04-21 15:44 ` Linus Torvalds
2022-04-21 23:30 ` Nicholas Piggin
2022-04-22 0:49 ` Linus Torvalds
2022-04-22 1:51 ` Nicholas Piggin
2022-04-22 2:31 ` Linus Torvalds
2022-04-22 2:57 ` Nicholas Piggin
2022-04-21 15:47 ` Edgecombe, Rick P [this message]
2022-04-21 16:15 ` Linus Torvalds
2022-04-22 0:12 ` Nicholas Piggin
2022-04-22 2:29 ` Edgecombe, Rick P
2022-04-22 2:47 ` Linus Torvalds
2022-04-22 16:54 ` Edgecombe, Rick P
2022-04-22 3:08 ` Nicholas Piggin
2022-04-22 4:31 ` Nicholas Piggin
2022-04-22 17:10 ` Edgecombe, Rick P
2022-04-22 20:22 ` Edgecombe, Rick P
2022-04-22 3:33 ` Nicholas Piggin
2022-04-21 9:47 ` Nicholas Piggin
2022-04-19 21:24 ` Luis Chamberlain
2022-04-19 23:58 ` Edgecombe, Rick P
2022-04-20 7:58 ` Petr Mladek
2022-04-19 18:20 ` Mike Rapoport
2022-04-24 17:43 ` Linus Torvalds
2022-04-25 6:48 ` Song Liu
2022-04-21 3:19 ` Nicholas Piggin
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