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Message-ID: <4BA883C0.2070102@kernel.org>
Date: Tue, 23 Mar 2010 02:02:56 -0700
From: Yinghai Lu <yinghai@...nel.org>
To: Ingo Molnar <mingo@...e.hu>
CC: Thomas Gleixner <tglx@...utronix.de>,
David Miller <davem@...emloft.net>,
Andrew Morton <akpm@...ux-foundation.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
benh@...nel.crashing.org, hpa@...or.com, jbarnes@...tuousgeek.org,
ebiederm@...ssion.com, linux-kernel@...r.kernel.org,
linux-arch@...r.kernel.org
Subject: Re: [PATCH 06/20] early_res: seperate common memmap func from e820.c
to fw_memmap.cy
On 03/23/2010 01:02 AM, Ingo Molnar wrote:
>
> * Yinghai Lu <yinghai@...nel.org> wrote:
>
>> please check
>>
>> [PATCH 01/20] x86: add find_e820_area_node
>>
>>
>> [RFC PATCH] x86: use lmb to replace early_res
>>
>> still keep kernel/early_res.c for the extension.
>>
>> should move those file to lib/lmb.c later?
>>
>> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
>>
>> ---
>> arch/x86/Kconfig | 1
>> arch/x86/include/asm/e820.h | 38 +-
>> arch/x86/include/asm/lmb.h | 8
>> arch/x86/kernel/e820.c | 163 +----------
>> arch/x86/kernel/head.c | 2
>> arch/x86/kernel/head32.c | 4
>> arch/x86/kernel/head64.c | 2
>> arch/x86/kernel/setup.c | 2
>> arch/x86/kernel/setup_percpu.c | 6
>> include/linux/early_res.h | 9
>> include/linux/lmb.h | 5
>> kernel/early_res.c | 594 ++++++++++++++++-------------------------
>> lib/lmb.c | 9
>> mm/page_alloc.c | 2
>> mm/sparse-vmemmap.c | 4
>> 15 files changed, 321 insertions(+), 528 deletions(-)
>
> That looks like a very promising direction!
>
> There's several things to do to make the approach fully clean:
>
> 1)
>
> I think we want to shape this as a series of simpler (and bisectable) patches.
will check it.
at least change include/linux/lmb.h and lib/lmb.c change could be sperated.
other looks a little bit hard.
>
> 2)
>
> I think we also need to concentrate the changes back into LMB:
yes. put them in kernel/early_res.c and move them to lmb.c if lmb gugs are happy with the change.
>
>> Index: linux-2.6/include/linux/early_res.h
>> ===================================================================
>> --- linux-2.6.orig/include/linux/early_res.h
>> +++ linux-2.6/include/linux/early_res.h
>> @@ -5,15 +5,18 @@
>> extern void reserve_early(u64 start, u64 end, char *name);
>> extern void reserve_early_overlap_ok(u64 start, u64 end, char *name);
>> extern void free_early(u64 start, u64 end);
>> -void free_early_partial(u64 start, u64 end);
>> extern void early_res_to_bootmem(u64 start, u64 end);
>>
>> -void reserve_early_without_check(u64 start, u64 end, char *name);
>> u64 find_early_area(u64 ei_start, u64 ei_last, u64 start, u64 end,
>> u64 size, u64 align);
>> u64 find_early_area_size(u64 ei_start, u64 ei_last, u64 start,
>> u64 *sizep, u64 align);
>> -u64 find_fw_memmap_area(u64 start, u64 end, u64 size, u64 align);
>> +u64 find_lmb_area(u64 start, u64 end, u64 size, u64 align);
>> +u64 find_lmb_area_size(u64 start, u64 *sizep, u64 align);
>> +u64 find_lmb_area_node(int nid, u64 start, u64 end, u64 size, u64 align);
>> +void lmb_register_active_regions(int nid, unsigned long start_pfn,
>> + unsigned long last_pfn);
>> +u64 lmb_hole_size(u64 start, u64 end);
>> u64 get_max_mapped(void);
>> #include <linux/range.h>
>> int get_free_all_memory_range(struct range **rangep, int nodeid);
>
> those new lmb_*() APIs should go into lmb.h.
next version
>
> 3)
>
> Furthermore, i think all of early_res.c should move into lmb.c as well and we
> should eliminate kernel/early_res.c.
>
> early_res.h will go away as well and all the new APIs will be in lmb.h.
current have three levels
a. old lmb users
b. x86 with bootmem
c. x86 with no-bootmem
some functions later could be moved to new bootmem.c
>
> 4)
>
> Also, we should move lib/lmb.c to mm/lmb.c, as now it's not just some optional
> library but _the_ main early-reserve memory subsystem used by the biggest
> Linux architectures.
yes
>
> 5)
>
> Could we perhaps also try to eliminate e820_*() method uses in arch/x86/, and
> replace them by lmb_*() API uses? (that too should be a step by step method,
> for bisectability)
yes.
except e820_any_mapped(,,E820_RESERVED)
others should not be used after fill_lmb_memory()
>
>> +++ linux-2.6/include/linux/lmb.h
>> @@ -26,7 +26,8 @@ struct lmb_property {
>> struct lmb_region {
>> unsigned long cnt;
>> u64 size;
>> - struct lmb_property region[MAX_LMB_REGIONS+1];
>> + struct lmb_property *region;
>> + unsigned long region_array_size;
>> };
>
> I suspect this should keep current LMB architectures still working, right?
they are still working. lmb_init will connect the pointers.
Index: linux-2.6/lib/lmb.c
===================================================================
--- linux-2.6.orig/lib/lmb.c
+++ linux-2.6/lib/lmb.c
@@ -18,6 +18,8 @@
#define LMB_ALLOC_ANYWHERE 0
struct lmb lmb;
+struct lmb_property lmb_memory_region[MAX_LMB_REGIONS + 1];
+struct lmb_property lmb_reserved_region[MAX_LMB_REGIONS + 1];
static int lmb_debug;
@@ -106,6 +108,11 @@ static void lmb_coalesce_regions(struct
void __init lmb_init(void)
{
+ lmb.memory.region = lmb_memory_region;
+ lmb.memory.region_array_size = ARRAY_SIZE(lmb_memory_region);
+ lmb.reserved.region = lmb_reserved_region;
+ lmb.reserved.region_array_size = ARRAY_SIZE(lmb_reserved_region);
+
/* Create a dummy zero size LMB which will get coalesced away later.
* This simplifies the lmb_add() code below...
*/
@@ -169,7 +176,7 @@ static long lmb_add_region(struct lmb_re
if (coalesced)
return coalesced;
- if (rgn->cnt >= MAX_LMB_REGIONS)
+ if (rgn->cnt >= (rgn->region_array_size - 1))
return -1;
Thanks
Yinghai
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