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author | Ingo Molnar <mingo@kernel.org> | 2016-02-08 11:57:34 +0300 |
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committer | Ingo Molnar <mingo@kernel.org> | 2016-02-08 14:14:25 +0300 |
commit | c1a0bf347c40dd4b0a5bb10fdf4de76a1fbbbe8c (patch) | |
tree | 969ea44ae90ea4f1ebd1ab42711eea0a10a2cb91 /arch/x86/mm | |
parent | b349e9a916772e867d0f9246d2978799897b2495 (diff) | |
download | linux-c1a0bf347c40dd4b0a5bb10fdf4de76a1fbbbe8c.tar.xz |
x86/mm/numa: Clean up numa_clear_kernel_node_hotplug()
So we fixed an overflow bug in numa_clear_kernel_node_hotplug():
2b54ab3c66d4 ("x86/mm/numa: Fix memory corruption on 32-bit NUMA kernels")
... and the bug was indirectly caused by poor coding style,
such as using start/end local variables unnecessarily, which
lost the physaddr_t type.
So make the code more readable and try to fully comment all
the thinking behind the logic.
No change in functionality.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: Chen Tang <imtangchen@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: PaX Team <pageexec@freemail.hu>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: y14sg1 <y14sg1@comcast.net>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm')
-rw-r--r-- | arch/x86/mm/numa.c | 65 |
1 files changed, 42 insertions, 23 deletions
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c index d04f8094bc23..ede4506abb18 100644 --- a/arch/x86/mm/numa.c +++ b/arch/x86/mm/numa.c @@ -465,46 +465,65 @@ static bool __init numa_meminfo_cover_memory(const struct numa_meminfo *mi) return true; } +/* + * Mark all currently memblock-reserved physical memory (which covers the + * kernel's own memory ranges) as hot-unswappable. + */ static void __init numa_clear_kernel_node_hotplug(void) { - int i, nid; - nodemask_t numa_kernel_nodes = NODE_MASK_NONE; - phys_addr_t start, end; - struct memblock_region *r; + nodemask_t reserved_nodemask = NODE_MASK_NONE; + struct memblock_region *mb_region; + int i; /* + * We have to do some preprocessing of memblock regions, to + * make them suitable for reservation. + * * At this time, all memory regions reserved by memblock are - * used by the kernel. Set the nid in memblock.reserved will - * mark out all the nodes the kernel resides in. + * used by the kernel, but those regions are not split up + * along node boundaries yet, and don't necessarily have their + * node ID set yet either. + * + * So iterate over all memory known to the x86 architecture, + * and use those ranges to set the nid in memblock.reserved. + * This will split up the memblock regions along node + * boundaries and will set the node IDs as well. */ for (i = 0; i < numa_meminfo.nr_blks; i++) { - struct numa_memblk *mb = &numa_meminfo.blk[i]; + struct numa_memblk *mb = numa_meminfo.blk + i; - memblock_set_node(mb->start, mb->end - mb->start, - &memblock.reserved, mb->nid); + memblock_set_node(mb->start, mb->end - mb->start, &memblock.reserved, mb->nid); } /* - * Mark all kernel nodes. + * Now go over all reserved memblock regions, to construct a + * node mask of all kernel reserved memory areas. * - * When booting with mem=nn[kMG] or in a kdump kernel, numa_meminfo - * may not include all the memblock.reserved memory ranges because - * trim_snb_memory() reserves specific pages for Sandy Bridge graphics. + * [ Note, when booting with mem=nn[kMG] or in a kdump kernel, + * numa_meminfo might not include all memblock.reserved + * memory ranges, because quirks such as trim_snb_memory() + * reserve specific pages for Sandy Bridge graphics. ] */ - for_each_memblock(reserved, r) - if (r->nid != MAX_NUMNODES) - node_set(r->nid, numa_kernel_nodes); + for_each_memblock(reserved, mb_region) { + if (mb_region->nid != MAX_NUMNODES) + node_set(mb_region->nid, reserved_nodemask); + } - /* Clear MEMBLOCK_HOTPLUG flag for memory in kernel nodes. */ + /* + * Finally, clear the MEMBLOCK_HOTPLUG flag for all memory + * belonging to the reserved node mask. + * + * Note that this will include memory regions that reside + * on nodes that contain kernel memory - entire nodes + * become hot-unpluggable: + */ for (i = 0; i < numa_meminfo.nr_blks; i++) { - nid = numa_meminfo.blk[i].nid; - if (!node_isset(nid, numa_kernel_nodes)) - continue; + struct numa_memblk *mb = numa_meminfo.blk + i; - start = numa_meminfo.blk[i].start; - end = numa_meminfo.blk[i].end; + if (!node_isset(mb->nid, reserved_nodemask)) + continue; - memblock_clear_hotplug(start, end - start); + memblock_clear_hotplug(mb->start, mb->end - mb->start); } } |