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Message-ID: <4C9457C5.5060307@kernel.org>
Date: Fri, 17 Sep 2010 23:10:13 -0700
From: Yinghai Lu <yinghai@...nel.org>
To: Jeremy Fitzhardinge <jeremy@...p.org>
CC: Ingo Molnar <mingo@...hat.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
the arch/x86 maintainers <x86@...nel.org>
Subject: Re: memblock vs early_res
On 09/17/2010 04:11 PM, Jeremy Fitzhardinge wrote:
> On 09/17/2010 03:47 PM, Yinghai Lu wrote:
>> On 09/17/2010 01:47 PM, Jeremy Fitzhardinge wrote:
>>> Hi Yinghai,
>>>
>>> I have the patch below floating around in my tree to make sure that
>>> early-reserved highmem is honoured when freeing unreserved memory. I
>>> was trying to rebase it to current linux-next and noticed that all the
>>> early_res stuff has been replaced with memblock.
>>>
>>> Is this still an issue? What would the memblock version of this patch
>>> look like?
>>>
>> Not sure why this patch is needed.
>>
>> For the early reserve ranges, that could be overlapped with high pages, is "KVA RAM",
>> but We do remove those range in active ranges array. [ in calculate_numa_remap_pages() ].
>> [
>> ...
>> memblock_x86_reserve_range(node_kva_final,
>> node_kva_final+(((u64)size)<<PAGE_SHIFT),
>> "KVA RAM");
>>
>> node_remap_start_pfn[nid] = node_kva_final>>PAGE_SHIFT;
>> remove_active_range(nid, node_remap_start_pfn[nid],
>> node_remap_start_pfn[nid] + size);
>> ...
>> ]
>>
>> Can you check if Gianluca Guida still can duplicate the problem that will need his patch ?
>
> The specific motivation for this patch is to handle Xen ballooning where
> the domain can be built with X pages of memory available to it
> initially, but Y pages are presented in the E820 map (Y >= X). The
> extra pages in the E820 are not physically present, but I want the
> kernel to allocate page structures for them, so I reserve_early() them
> to stop them from being used. Later on, the balloon driver can
> incrementally populate these pfns and return them to the kernel for use
> as real memory.
>
> Without this patch, the reservations of the highmem pages are ignored
> and the kernel ends up trying to use these non-resident pages. (At
> least that's what used to happen, and I didn't see any changes which
> looked like they would address this.)
>
> Does the code you quote above address this case?
please check
[PATCH] x86, mm, memblock, 32bit: Make higepages honor early reserved ranges
Originally the only early reserved range that is overlapped with high pages :
"KVA RAM", but We do remove them from active ranges.
It turns out xen could have that kind of overlapping to support memory bollaon.
So We need to make add_highpage_with_active_regions() to subtract memblock
reserved just like low ram.
In this patch, refactering get_freel_all_memory_range() to make it can be used
by add_highpage_with_active_regions().
Also we don't need to remove "KVA RAM" from active ranges.
Signed-off-by: Yinghai Lu <yinghai@...nel.org>
---
arch/x86/include/asm/memblock.h | 2 +
arch/x86/mm/init_32.c | 59 ++++++++++++----------------------------
arch/x86/mm/memblock.c | 19 ++++++++++--
arch/x86/mm/numa_32.c | 2 -
4 files changed, 36 insertions(+), 46 deletions(-)
Index: linux-2.6/arch/x86/include/asm/memblock.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/memblock.h
+++ linux-2.6/arch/x86/include/asm/memblock.h
@@ -9,6 +9,8 @@ void memblock_x86_to_bootmem(u64 start,
void memblock_x86_reserve_range(u64 start, u64 end, char *name);
void memblock_x86_free_range(u64 start, u64 end);
struct range;
+int __get_free_all_memory_range(struct range **range, int nodeid,
+ unsigned long start_pfn, unsigned long end_pfn);
int get_free_all_memory_range(struct range **rangep, int nodeid);
void memblock_x86_register_active_regions(int nid, unsigned long start_pfn,
Index: linux-2.6/arch/x86/mm/init_32.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/init_32.c
+++ linux-2.6/arch/x86/mm/init_32.c
@@ -426,49 +426,28 @@ static void __init add_one_highpage_init
totalhigh_pages++;
}
-struct add_highpages_data {
- unsigned long start_pfn;
- unsigned long end_pfn;
-};
-
-static int __init add_highpages_work_fn(unsigned long start_pfn,
- unsigned long end_pfn, void *datax)
+void __init add_highpages_with_active_regions(int nid,
+ unsigned long start_pfn, unsigned long end_pfn)
{
- int node_pfn;
- struct page *page;
- unsigned long final_start_pfn, final_end_pfn;
- struct add_highpages_data *data;
-
- data = (struct add_highpages_data *)datax;
-
- final_start_pfn = max(start_pfn, data->start_pfn);
- final_end_pfn = min(end_pfn, data->end_pfn);
- if (final_start_pfn >= final_end_pfn)
- return 0;
-
- for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
- node_pfn++) {
- if (!pfn_valid(node_pfn))
- continue;
- page = pfn_to_page(node_pfn);
- add_one_highpage_init(page);
+ struct range *range;
+ int nr_range;
+ int i;
+
+ nr_range = __get_free_all_memory_range(&range, nid, start_pfn, end_pfn);
+
+ for (i = 0; i < nr_range; i++) {
+ struct page *page;
+ int node_pfn;
+
+ for (node_pfn = range[i].start; node_pfn < range[i].end;
+ node_pfn++) {
+ if (!pfn_valid(node_pfn))
+ continue;
+ page = pfn_to_page(node_pfn);
+ add_one_highpage_init(page);
+ }
}
-
- return 0;
-
}
-
-void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
- unsigned long end_pfn)
-{
- struct add_highpages_data data;
-
- data.start_pfn = start_pfn;
- data.end_pfn = end_pfn;
-
- work_with_active_regions(nid, add_highpages_work_fn, &data);
-}
-
#else
static inline void permanent_kmaps_init(pgd_t *pgd_base)
{
Index: linux-2.6/arch/x86/mm/memblock.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/memblock.c
+++ linux-2.6/arch/x86/mm/memblock.c
@@ -139,7 +139,8 @@ static int __init count_early_node_map(i
return data.nr;
}
-int __init get_free_all_memory_range(struct range **rangep, int nodeid)
+int __init __get_free_all_memory_range(struct range **rangep, int nodeid,
+ unsigned long start_pfn, unsigned long end_pfn)
{
int count;
struct range *range;
@@ -155,9 +156,9 @@ int __init get_free_all_memory_range(str
* at first
*/
nr_range = add_from_early_node_map(range, count, nr_range, nodeid);
-#ifdef CONFIG_X86_32
- subtract_range(range, count, max_low_pfn, -1ULL);
-#endif
+ subtract_range(range, count, 0, start_pfn);
+ subtract_range(range, count, end_pfn, -1ULL);
+
memblock_x86_subtract_reserved(range, count);
nr_range = clean_sort_range(range, count);
@@ -165,6 +166,16 @@ int __init get_free_all_memory_range(str
return nr_range;
}
+int __init get_free_all_memory_range(struct range **rangep, int nodeid)
+{
+ unsigned long end_pfn = -1ULL;
+
+#ifdef CONFIG_X86_32
+ end_pfn = max_low_pfn;
+#endif
+ return __get_free_all_memory_range(rangep, nodeid, 0, end_pfn);
+}
+
static u64 __init __memblock_x86_memory_in_range(u64 addr, u64 limit, bool get_free)
{
int i, count;
Index: linux-2.6/arch/x86/mm/numa_32.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/numa_32.c
+++ linux-2.6/arch/x86/mm/numa_32.c
@@ -326,8 +326,6 @@ static __init unsigned long calculate_nu
"KVA RAM");
node_remap_start_pfn[nid] = node_kva_final>>PAGE_SHIFT;
- remove_active_range(nid, node_remap_start_pfn[nid],
- node_remap_start_pfn[nid] + size);
}
printk(KERN_INFO "Reserving total of %lx pages for numa KVA remap\n",
reserve_pages);
--
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