From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
David Hildenbrand <david@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Michal Hocko <mhocko@kernel.org>, Michal Hocko <mhocko@suse.com>,
Mike Rapoport <rppt@kernel.org>,
Nicholas Piggin <npiggin@gmail.com>,
Oscar Salvador <osalvador@suse.de>,
Paul Mackerras <paulus@samba.org>,
Rashmica Gupta <rashmica.g@gmail.com>,
Wei Yang <richard.weiyang@linux.alibaba.com>
Subject: [PATCH v2 0/8] powernv/memtrace: don't abuse memory hot(un)plug infrastructure for memory allocations
Date: Wed, 11 Nov 2020 15:53:14 +0100 [thread overview]
Message-ID: <20201111145322.15793-1-david@redhat.com> (raw)
Based on latest linux/master
powernv/memtrace is the only in-kernel user that rips out random memory
it never added (doesn't own) in order to allocate memory without a
linear mapping. Let's stop abusing memory hot(un)plug infrastructure for
that - use alloc_contig_pages() for allocating memory and remove the
linear mapping manually.
The original idea was discussed in:
https://lkml.kernel.org/r/48340e96-7e6b-736f-9e23-d3111b915b6e@redhat.com
I only tested via QEMU TCG with a single NUMA node- see patch #8 for more
details.
Error handling and cleanup handling in memtrace code is a mess - that
should definitely get cleaned up sooner or later. Once we have __GFP_ZERO
support for alloc_contig_pages(), we can drop manual clearing. I added
a TODO for now, so this series can go via the powerpc tree - the __GFP_ZERO
change is then better suited via the mm tree, along with support for
__GFP_ZERO.
v1 -> v2:
- Tweaks to patch descriptions
- "powernv/memtrace: don't leak kernel memory to user space"
-- Added. Reported by Michael.
- "powernv/memtrace: fix crashing the kernel when enabling concurrently"
-- Added, discovered while testing.
- "powerpc/mm: protect linear mapping modifications by a mutex"
-- Added. Although we currently won't have concurrency, this is cleaner and
future-proof.
- "powerepc/book3s64/hash: drop WARN_ON in hash__remove_section_mapping"
-- Added. Suggested by Oscar
- "powernv/memtrace: don't abuse memory hot(un)plug infrastructure for
memory allocations"
-- Reshuffle the code to make review easier.
-- Add a TODO regarding __GFP_ZERO. Adapt to changed page clearing code.
-- Use GFP_KERNEL | __GFP_THISNODE | __GFP_NOWARN for allocations.
David Hildenbrand (8):
powernv/memtrace: don't leak kernel memory to user space
powernv/memtrace: fix crashing the kernel when enabling concurrently
powerpc/mm: factor out creating/removing linear mapping
powerpc/mm: protect linear mapping modifications by a mutex
powerpc/mm: print warning in arch_remove_linear_mapping()
powerepc/book3s64/hash: drop WARN_ON in hash__remove_section_mapping
powerpc/mm: remove linear mapping if __add_pages() fails in
arch_add_memory()
powernv/memtrace: don't abuse memory hot(un)plug infrastructure for
memory allocations
arch/powerpc/mm/book3s64/hash_utils.c | 1 -
arch/powerpc/mm/mem.c | 53 +++++--
arch/powerpc/platforms/powernv/Kconfig | 8 +-
arch/powerpc/platforms/powernv/memtrace.c | 175 ++++++++++------------
include/linux/memory_hotplug.h | 3 +
5 files changed, 125 insertions(+), 115 deletions(-)
--
2.26.2
next reply other threads:[~2020-11-11 14:53 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-11 14:53 David Hildenbrand [this message]
2020-11-11 14:53 ` [PATCH v2 1/8] powernv/memtrace: don't leak kernel memory to user space David Hildenbrand
2020-11-17 15:13 ` Oscar Salvador
2020-11-11 14:53 ` [PATCH v2 2/8] powernv/memtrace: fix crashing the kernel when enabling concurrently David Hildenbrand
2020-11-17 15:22 ` Oscar Salvador
2020-11-11 14:53 ` [PATCH v2 3/8] powerpc/mm: factor out creating/removing linear mapping David Hildenbrand
2020-11-17 15:27 ` Oscar Salvador
2020-11-11 14:53 ` [PATCH v2 4/8] powerpc/mm: protect linear mapping modifications by a mutex David Hildenbrand
2020-11-17 15:37 ` Oscar Salvador
2020-11-17 15:46 ` David Hildenbrand
2020-11-11 14:53 ` [PATCH v2 5/8] powerpc/mm: print warning in arch_remove_linear_mapping() David Hildenbrand
2020-11-11 14:53 ` [PATCH v2 6/8] powerepc/book3s64/hash: drop WARN_ON in hash__remove_section_mapping David Hildenbrand
2020-11-17 15:45 ` Oscar Salvador
2020-11-11 14:53 ` [PATCH v2 7/8] powerpc/mm: remove linear mapping if __add_pages() fails in arch_add_memory() David Hildenbrand
2020-11-17 15:51 ` Oscar Salvador
2020-11-17 15:53 ` David Hildenbrand
2020-11-18 2:00 ` Michael Ellerman
2020-11-11 14:53 ` [PATCH v2 8/8] powernv/memtrace: don't abuse memory hot(un)plug infrastructure for memory allocations David Hildenbrand
2020-11-17 16:45 ` Oscar Salvador
2020-11-25 11:57 ` [PATCH v2 0/8] " Michael Ellerman
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