Messages in this thread Patch in this message | | | Date | Fri, 21 Mar 2008 12:44:04 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] mm: fix boundary checking in free_bootmem_core |
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On Fri, 14 Mar 2008 10:36:52 -0700 "Yinghai Lu" <yhlu.kernel@gmail.com> wrote:
> On Fri, Mar 14, 2008 at 9:53 AM, Andi Kleen <andi@firstfloor.org> wrote: > > On Fri, Mar 14, 2008 at 09:44:50AM -0700, Yinghai Lu wrote: > > > On 14 Mar 2008 12:58:44 +0100, Andi Kleen <andi@firstfloor.org> wrote: > > > > "Yinghai Lu" <yhlu.kernel@gmail.com> writes: > > > > > > > > > > then i tried to reserve 64M or 128M RAM before that, and free that > > > > > before gart/switotble try to allloc_bootmem under 4g. > > > > > > > > Sounds like an incredible hack. There are far better ways to do that > > > > for bootmem allocations. e.g. you can just specify a high enough "goal" > > > > That is how swiotlb solves a similar problem (at least before my > > > > mask allocator rewrite) > > > > > > I don't think so. > > > > > > anyway, otherway to workaround it is > > > change > > > return __earlyonly_bootmem_alloc(node, size, size, > > > __pa(MAX_DMA_ADDRESS)); > > > in vmemmap_alloc_block to > > > return __earlyonly_bootmem_alloc(node, size, size, > > > __pa(MAX_DMA_ADDRESS + (1<<27))); > > > to make room for gart. but that is global change. and may affect other > > > platform. > > > > You can just make it an optional architecture defined macro > it is hard to use MACRO, if someone have allsysconfig, that will make > kernel code use a lot. > > > > > > > and don't make sure gart will get it. > > > > Has nothing to do with the gart? > > > > > > > > > > > > also i assume swiotlb need that range is less than 4g. > > > > The normal rule is that anybody who needs big bootmem allocations > > need to make sure they're high enough to not fill up first 4GB. > > For small allocations like most of bootmem it doesn't matter because > > they're, um, small. > > > > If vmemmap doesn't do that vmemmap needs to be fixed. > > how to define big? > it has hundreds of 2M block. when numa is on, they span on all nodes, > and if numa is off, they are sitting on first_online_node. >
So Ingo has now merged some x86 patches which apparently had a dependency upon this patch: "otherwise free_bootmem_node in dma32_free could do sth bad.".
I had this patch on hold awaiting conclusive feedback from Andi. It looks like it needs to be merged asap and any remaining problems should be addressed separately.
Here's what I have:
From: "Yinghai Lu" <yhlu.kernel@gmail.com>
With numa enabled, some callers could have a range o fmemory on one node but try to free that on other node. This can cause some pages to be freed wrongly.
For example: when we try to allocate 128g boot ram early for gart/swiotlb, and free that range later so gart/swiotlb can get some range afterwards.
With this patch, we don't need to care which node holds the range, just loop to call free_bootmem_node for all online nodes.
This patch makes free_bootmem_core() more robust by trimming the sidx and eidx according the ram range that the node has.
And make the free_bootmem_core handle this out of range case. We could use bdata_list to make sure the range can be freed for sure. So next time, we don't need to loop online nodes and could use free_bootmem directly.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Cc: Andi Kleen <ak@suse.de> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> ---
mm/bootmem.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-)
diff -puN mm/bootmem.c~mm-fix-boundary-checking-in-free_bootmem_core mm/bootmem.c --- a/mm/bootmem.c~mm-fix-boundary-checking-in-free_bootmem_core +++ a/mm/bootmem.c @@ -125,6 +125,7 @@ static int __init reserve_bootmem_core(b BUG_ON(!size); BUG_ON(PFN_DOWN(addr) >= bdata->node_low_pfn); BUG_ON(PFN_UP(addr + size) > bdata->node_low_pfn); + BUG_ON(addr < bdata->node_boot_start); sidx = PFN_DOWN(addr - bdata->node_boot_start); eidx = PFN_UP(addr + size - bdata->node_boot_start); @@ -156,21 +157,31 @@ static void __init free_bootmem_core(boo unsigned long sidx, eidx; unsigned long i; + BUG_ON(!size); + + /* out range */ + if (addr + size < bdata->node_boot_start || + PFN_DOWN(addr) > bdata->node_low_pfn) + return; /* * round down end of usable mem, partially free pages are * considered reserved. */ - BUG_ON(!size); - BUG_ON(PFN_DOWN(addr + size) > bdata->node_low_pfn); - if (addr < bdata->last_success) + if (addr >= bdata->node_boot_start && addr < bdata->last_success) bdata->last_success = addr; /* - * Round up the beginning of the address. + * Round up to index to the range. */ - sidx = PFN_UP(addr) - PFN_DOWN(bdata->node_boot_start); + if (PFN_UP(addr) > PFN_DOWN(bdata->node_boot_start)) + sidx = PFN_UP(addr) - PFN_DOWN(bdata->node_boot_start); + else + sidx = 0; + eidx = PFN_DOWN(addr + size - bdata->node_boot_start); + if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start)) + eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start); for (i = sidx; i < eidx; i++) { if (unlikely(!test_and_clear_bit(i, bdata->node_bootmem_map))) @@ -421,7 +432,9 @@ int __init reserve_bootmem(unsigned long void __init free_bootmem(unsigned long addr, unsigned long size) { - free_bootmem_core(NODE_DATA(0)->bdata, addr, size); + bootmem_data_t *bdata; + list_for_each_entry(bdata, &bdata_list, list) + free_bootmem_core(bdata, addr, size); } unsigned long __init free_all_bootmem(void) _
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