[PATCH v2] delete unnecessary bootmem struct page array

[PATCH v2] delete unnecessary bootmem struct page array

[Real Name]

From: Honggang Li <enjoymindful@gmail.com>

The patch based on linux-next-2014-06-02.

The old init_maps function does two things:
1) allocates and initializes one struct page array for bootmem
2) count the number of total pages

After removed the source code related to the unnecessary array, the name 
'init_maps' is some kind of improper named, as it just count the number of
total page numbers. So, I renamed the function as 'mem_total_pages'.

I tested the patch through repeat reboot the uml kernel many times.
[real@name linux-next]$ make ARCH=um defconfig
[real@name linux-next]$ make ARCH=um linux
[real@name linux-next]$ file linux
linux: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, not stripped
[real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 1
[real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 2
(repeat reboot the uml kernel many times..)

Honggang Li (1):
  delete unnecessary bootmem struct page array

 arch/um/include/shared/mem_user.h |  2 +-
 arch/um/kernel/physmem.c          | 32 ++++++--------------------------
 arch/um/kernel/um_arch.c          |  7 +------
 3 files changed, 8 insertions(+), 33 deletions(-)

-- 
1.8.3.1

[uml-devel] [PATCH v2] delete unnecessary bootmem struct page array

[Real Name]

From: Honggang Li <enjoymindful@gmail.com>

The patch based on linux-next-2014-06-02.

The old init_maps function does two things:
1) allocates and initializes one struct page array for bootmem
2) count the number of total pages

After removed the source code related to the unnecessary array, the name 
'init_maps' is some kind of improper named, as it just count the number of
total page numbers. So, I renamed the function as 'mem_total_pages'.

I tested the patch through repeat reboot the uml kernel many times.
[real@name linux-next]$ make ARCH=um defconfig
[real@name linux-next]$ make ARCH=um linux
[real@name linux-next]$ file linux
linux: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, not stripped
[real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 1
[real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 2
(repeat reboot the uml kernel many times..)

Honggang Li (1):
  delete unnecessary bootmem struct page array

 arch/um/include/shared/mem_user.h |  2 +-
 arch/um/kernel/physmem.c          | 32 ++++++--------------------------
 arch/um/kernel/um_arch.c          |  7 +------
 3 files changed, 8 insertions(+), 33 deletions(-)

-- 
1.8.3.1


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[PATCH] delete unnecessary bootmem struct page array

[Real Name]

From: Honggang Li <enjoymindful@gmail.com>

1) uml kernel bootmem managed through bootmem_data->node_bootmem_map,
not the struct page array, so the array is unnecessary.

2) the bootmem struct page array has been pointed by a *local* pointer,
struct page *map, in init_maps function. The array can be accessed only
in init_maps's scope. As a result, uml kernel wastes about 1% of total
memory.

Signed-off-by: Honggang Li <enjoymindful@gmail.com>
---
 arch/um/include/shared/mem_user.h |  2 +-
 arch/um/kernel/physmem.c          | 32 ++++++--------------------------
 arch/um/kernel/um_arch.c          |  7 +------
 3 files changed, 8 insertions(+), 33 deletions(-)

diff --git a/arch/um/include/shared/mem_user.h b/arch/um/include/shared/mem_user.h
index 46384ac..cb84414 100644
--- a/arch/um/include/shared/mem_user.h
+++ b/arch/um/include/shared/mem_user.h
@@ -49,7 +49,7 @@ extern int iomem_size;
 extern int init_mem_user(void);
 extern void setup_memory(void *entry);
 extern unsigned long find_iomem(char *driver, unsigned long *len_out);
-extern int init_maps(unsigned long physmem, unsigned long iomem,
+extern void mem_total_pages(unsigned long physmem, unsigned long iomem,
 		     unsigned long highmem);
 extern unsigned long get_vm(unsigned long len);
 extern void setup_physmem(unsigned long start, unsigned long usable,
diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c
index 30fdd5d..549ecf3 100644
--- a/arch/um/kernel/physmem.c
+++ b/arch/um/kernel/physmem.c
@@ -22,39 +22,19 @@ EXPORT_SYMBOL(high_physmem);
 
 extern unsigned long long physmem_size;
 
-int __init init_maps(unsigned long physmem, unsigned long iomem,
+void __init mem_total_pages(unsigned long physmem, unsigned long iomem,
 		     unsigned long highmem)
 {
-	struct page *p, *map;
-	unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
-	unsigned long iomem_len, iomem_pages, total_len, total_pages;
-	int i;
-
-	phys_pages = physmem >> PAGE_SHIFT;
-	phys_len = phys_pages * sizeof(struct page);
-
-	iomem_pages = iomem >> PAGE_SHIFT;
-	iomem_len = iomem_pages * sizeof(struct page);
+	unsigned long phys_pages, highmem_pages;
+	unsigned long iomem_pages, total_pages;
 
+	phys_pages    = physmem >> PAGE_SHIFT;
+	iomem_pages   = iomem   >> PAGE_SHIFT;
 	highmem_pages = highmem >> PAGE_SHIFT;
-	highmem_len = highmem_pages * sizeof(struct page);
-
-	total_pages = phys_pages + iomem_pages + highmem_pages;
-	total_len = phys_len + iomem_len + highmem_len;
 
-	map = alloc_bootmem_low_pages(total_len);
-	if (map == NULL)
-		return -ENOMEM;
-
-	for (i = 0; i < total_pages; i++) {
-		p = &map[i];
-		memset(p, 0, sizeof(struct page));
-		SetPageReserved(p);
-		INIT_LIST_HEAD(&p->lru);
-	}
+	total_pages   = phys_pages + iomem_pages + highmem_pages;
 
 	max_mapnr = total_pages;
-	return 0;
 }
 
 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 6043c76..dbd5bda 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -338,12 +338,7 @@ int __init linux_main(int argc, char **argv)
 	start_vm = VMALLOC_START;
 
 	setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
-	if (init_maps(physmem_size, iomem_size, highmem)) {
-		printf("Failed to allocate mem_map for %Lu bytes of physical "
-		       "memory and %Lu bytes of highmem\n", physmem_size,
-		       highmem);
-		exit(1);
-	}
+	mem_total_pages(physmem_size, iomem_size, highmem);
 
 	virtmem_size = physmem_size;
 	stack = (unsigned long) argv;
-- 
1.8.3.1

[uml-devel] [PATCH] delete unnecessary bootmem struct page array

[Real Name]

From: Honggang Li <enjoymindful@gmail.com>

1) uml kernel bootmem managed through bootmem_data->node_bootmem_map,
not the struct page array, so the array is unnecessary.

2) the bootmem struct page array has been pointed by a *local* pointer,
struct page *map, in init_maps function. The array can be accessed only
in init_maps's scope. As a result, uml kernel wastes about 1% of total
memory.

Signed-off-by: Honggang Li <enjoymindful@gmail.com>
---
 arch/um/include/shared/mem_user.h |  2 +-
 arch/um/kernel/physmem.c          | 32 ++++++--------------------------
 arch/um/kernel/um_arch.c          |  7 +------
 3 files changed, 8 insertions(+), 33 deletions(-)

diff --git a/arch/um/include/shared/mem_user.h b/arch/um/include/shared/mem_user.h
index 46384ac..cb84414 100644
--- a/arch/um/include/shared/mem_user.h
+++ b/arch/um/include/shared/mem_user.h
@@ -49,7 +49,7 @@ extern int iomem_size;
 extern int init_mem_user(void);
 extern void setup_memory(void *entry);
 extern unsigned long find_iomem(char *driver, unsigned long *len_out);
-extern int init_maps(unsigned long physmem, unsigned long iomem,
+extern void mem_total_pages(unsigned long physmem, unsigned long iomem,
 		     unsigned long highmem);
 extern unsigned long get_vm(unsigned long len);
 extern void setup_physmem(unsigned long start, unsigned long usable,
diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c
index 30fdd5d..549ecf3 100644
--- a/arch/um/kernel/physmem.c
+++ b/arch/um/kernel/physmem.c
@@ -22,39 +22,19 @@ EXPORT_SYMBOL(high_physmem);
 
 extern unsigned long long physmem_size;
 
-int __init init_maps(unsigned long physmem, unsigned long iomem,
+void __init mem_total_pages(unsigned long physmem, unsigned long iomem,
 		     unsigned long highmem)
 {
-	struct page *p, *map;
-	unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
-	unsigned long iomem_len, iomem_pages, total_len, total_pages;
-	int i;
-
-	phys_pages = physmem >> PAGE_SHIFT;
-	phys_len = phys_pages * sizeof(struct page);
-
-	iomem_pages = iomem >> PAGE_SHIFT;
-	iomem_len = iomem_pages * sizeof(struct page);
+	unsigned long phys_pages, highmem_pages;
+	unsigned long iomem_pages, total_pages;
 
+	phys_pages    = physmem >> PAGE_SHIFT;
+	iomem_pages   = iomem   >> PAGE_SHIFT;
 	highmem_pages = highmem >> PAGE_SHIFT;
-	highmem_len = highmem_pages * sizeof(struct page);
-
-	total_pages = phys_pages + iomem_pages + highmem_pages;
-	total_len = phys_len + iomem_len + highmem_len;
 
-	map = alloc_bootmem_low_pages(total_len);
-	if (map == NULL)
-		return -ENOMEM;
-
-	for (i = 0; i < total_pages; i++) {
-		p = &map[i];
-		memset(p, 0, sizeof(struct page));
-		SetPageReserved(p);
-		INIT_LIST_HEAD(&p->lru);
-	}
+	total_pages   = phys_pages + iomem_pages + highmem_pages;
 
 	max_mapnr = total_pages;
-	return 0;
 }
 
 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 6043c76..dbd5bda 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -338,12 +338,7 @@ int __init linux_main(int argc, char **argv)
 	start_vm = VMALLOC_START;
 
 	setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
-	if (init_maps(physmem_size, iomem_size, highmem)) {
-		printf("Failed to allocate mem_map for %Lu bytes of physical "
-		       "memory and %Lu bytes of highmem\n", physmem_size,
-		       highmem);
-		exit(1);
-	}
+	mem_total_pages(physmem_size, iomem_size, highmem);
 
 	virtmem_size = physmem_size;
 	stack = (unsigned long) argv;
-- 
1.8.3.1


------------------------------------------------------------------------------
Learn Graph Databases - Download FREE O'Reilly Book
"Graph Databases" is the definitive new guide to graph databases and their 
applications. Written by three acclaimed leaders in the field, 
this first edition is now available. Download your free book today!
http://p.sf.net/sfu/NeoTech
_______________________________________________
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Re: [PATCH v2] delete unnecessary bootmem struct page array

[Real Name]

Hi, Richard
 Any comment about this patch?
thanks

On Tue, Jun 03, 2014 at 01:30:44PM +0800, Real Name wrote:
> From: Honggang Li <enjoymindful@gmail.com>
> 
> The patch based on linux-next-2014-06-02.
> 
> The old init_maps function does two things:
> 1) allocates and initializes one struct page array for bootmem
> 2) count the number of total pages
> 
> After removed the source code related to the unnecessary array, the name 
> 'init_maps' is some kind of improper named, as it just count the number of
> total page numbers. So, I renamed the function as 'mem_total_pages'.
> 
> I tested the patch through repeat reboot the uml kernel many times.
> [real@name linux-next]$ make ARCH=um defconfig
> [real@name linux-next]$ make ARCH=um linux
> [real@name linux-next]$ file linux
> linux: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, not stripped
> [real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 1
> [real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 2
> (repeat reboot the uml kernel many times..)
> 
> Honggang Li (1):
>   delete unnecessary bootmem struct page array
> 
>  arch/um/include/shared/mem_user.h |  2 +-
>  arch/um/kernel/physmem.c          | 32 ++++++--------------------------
>  arch/um/kernel/um_arch.c          |  7 +------
>  3 files changed, 8 insertions(+), 33 deletions(-)
> 
> -- 
> 1.8.3.1
> 

Re: [uml-devel] [PATCH v2] delete unnecessary bootmem struct page array

[Toralf Förster]

On 06/09/2014 07:49 AM, Real Name wrote:
> Hi, Richard
>  Any comment about this patch?
> thanks
> 
> On Tue, Jun 03, 2014 at 01:30:44PM +0800, Real Name wrote:
>> From: Honggang Li <enjoymindful@gmail.com>

Hi "Real Name",

give Richard a little bit more time to comment/react.

UML is rather a hobby of him in it spare time than his full time job.

;)


-- 
Toralf

Re: [PATCH v2] delete unnecessary bootmem struct page array

[Richard Weinberger]

Hi!

Am 03.06.2014 07:30, schrieb Real Name:
> From: Honggang Li <enjoymindful@gmail.com>
> 
> The patch based on linux-next-2014-06-02.
> 
> The old init_maps function does two things:
> 1) allocates and initializes one struct page array for bootmem
> 2) count the number of total pages
> 
> After removed the source code related to the unnecessary array, the name 
> 'init_maps' is some kind of improper named, as it just count the number of
> total page numbers. So, I renamed the function as 'mem_total_pages'.
> 
> I tested the patch through repeat reboot the uml kernel many times.
> [real@name linux-next]$ make ARCH=um defconfig
> [real@name linux-next]$ make ARCH=um linux
> [real@name linux-next]$ file linux
> linux: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, not stripped
> [real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 1
> [real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 2
> (repeat reboot the uml kernel many times..)

Can you please include in the changelog the commit sha1 which made the old init_maps() obsolete?
I had a look at the pre-git linux tree, looks like init_maps() wasn't touched for more than 10 years.

Thanks,
//richard

> Honggang Li (1):
>   delete unnecessary bootmem struct page array
> 
>  arch/um/include/shared/mem_user.h |  2 +-
>  arch/um/kernel/physmem.c          | 32 ++++++--------------------------
>  arch/um/kernel/um_arch.c          |  7 +------
>  3 files changed, 8 insertions(+), 33 deletions(-)
> 

Re: [PATCH v2] delete unnecessary bootmem struct page array

[Real Name]

On Sat, Jun 14, 2014 at 11:44:04AM +0200, Richard Weinberger wrote:
> Hi!
> 
> Am 03.06.2014 07:30, schrieb Real Name:
> > From: Honggang Li <enjoymindful@gmail.com>
> > 
> > The patch based on linux-next-2014-06-02.
> > 
> > The old init_maps function does two things:
> > 1) allocates and initializes one struct page array for bootmem
> > 2) count the number of total pages
> > 
> > After removed the source code related to the unnecessary array, the name 
> > 'init_maps' is some kind of improper named, as it just count the number of
> > total page numbers. So, I renamed the function as 'mem_total_pages'.
> > 
> > I tested the patch through repeat reboot the uml kernel many times.
> > [real@name linux-next]$ make ARCH=um defconfig
> > [real@name linux-next]$ make ARCH=um linux
> > [real@name linux-next]$ file linux
> > linux: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, not stripped
> > [real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 1
> > [real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 2
> > (repeat reboot the uml kernel many times..)
> 
> Can you please include in the changelog the commit sha1 which made the old init_maps() obsolete?
> I had a look at the pre-git linux tree, looks like init_maps() wasn't touched for more than 10 years.

hi, richard

what is the pre-git linux tree? I searched it with google, but failed.

The v2.6.12 kernel is the oldest one available from the linux-next git tree. And it has duplicated
struct page arrays. So, any suggestion how to find the commit you wanted?

linux-2.4.20 + uml-patch-2.4.20-8 works on *old* redhat-9 virtual machine. And it seems has duplicated
struct page array too.

The first struct page array
------------------------
linux-2.4.20/arch/um/kernel/physmem.c
157 int init_maps(unsigned long len)
158 {
159         struct page *p, *map;
160         int i, n;
161 
162         n = len >> PAGE_SHIFT;
163         len = n * sizeof(struct page);
164 
165         if(kmalloc_ok){
166                 map = kmalloc(len, GFP_KERNEL);
167                 if(map == NULL) map = vmalloc(len);
168         }
169         else map = alloc_bootmem_low_pages(len);
170 
171         if(map == NULL)
172                 return(-ENOMEM);
173 
174         for(i = 0; i < n; i++){
175                 p = &map[i];
176                 set_page_count(p, 0);
177                 SetPageReserved(p);
178                 INIT_LIST_HEAD(&p->list);
179         }
180 
181         mem_map = map;
182         max_mapnr = n;
183         return(0);
184 }


The second struct page array
-----------------------
mm/memory.c
73 mem_map_t * mem_map; // global define

mm/page_alloc.c
839 void __init free_area_init(unsigned long *zones_size)
840 {
841         free_area_init_core(0, &contig_page_data, &mem_map, zones_size, 0, 0, 0);
842 }

--------
mm/page_alloc.c
685 void __init free_area_init_core(int nid, pg_data_t *pgdat, struct page **gmap,
686         unsigned long *zones_size, unsigned long zone_start_paddr,
687         unsigned long *zholes_size, struct page *lmem_map)
688 {
........
716         map_size = (totalpages + 1)*sizeof(struct page);
717         if (lmem_map == (struct page *)0) {
718                 lmem_map = (struct page *) alloc_bootmem_node(pgdat, map_size);
719                 lmem_map = (struct page *)(PAGE_OFFSET +
720                         MAP_ALIGN((unsigned long)lmem_map - PAGE_OFFSET));
721         }
722         *gmap = pgdat->node_mem_map = lmem_map;


> 
> Thanks,
> //richard
> 
> > Honggang Li (1):
> >   delete unnecessary bootmem struct page array
> > 
> >  arch/um/include/shared/mem_user.h |  2 +-
> >  arch/um/kernel/physmem.c          | 32 ++++++--------------------------
> >  arch/um/kernel/um_arch.c          |  7 +------
> >  3 files changed, 8 insertions(+), 33 deletions(-)
> > 

Re: [uml-devel] [PATCH v2] delete unnecessary bootmem struct page array

[Real Name]

On Sat, Jun 14, 2014 at 11:44:04AM +0200, Richard Weinberger wrote:
> Hi!
> 
> Am 03.06.2014 07:30, schrieb Real Name:
> > From: Honggang Li <enjoymindful@gmail.com>
> > 
> > The patch based on linux-next-2014-06-02.
> > 
> > The old init_maps function does two things:
> > 1) allocates and initializes one struct page array for bootmem
> > 2) count the number of total pages
> > 
> > After removed the source code related to the unnecessary array, the name 
> > 'init_maps' is some kind of improper named, as it just count the number of
> > total page numbers. So, I renamed the function as 'mem_total_pages'.
> > 
> > I tested the patch through repeat reboot the uml kernel many times.
> > [real@name linux-next]$ make ARCH=um defconfig
> > [real@name linux-next]$ make ARCH=um linux
> > [real@name linux-next]$ file linux
> > linux: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, not stripped
> > [real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 1
> > [real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 2
> > (repeat reboot the uml kernel many times..)
> 
> Can you please include in the changelog the commit sha1 which made the old init_maps() obsolete?
> I had a look at the pre-git linux tree, looks like init_maps() wasn't touched for more than 10 years.

hi, richard

what is the pre-git linux tree? I searched it with google, but failed.

The v2.6.12 kernel is the oldest one available from the linux-next git tree. And it has duplicated
struct page arrays. So, any suggestion how to find the commit you wanted?

linux-2.4.20 + uml-patch-2.4.20-8 works on *old* redhat-9 virtual machine. And it seems has duplicated
struct page array too.

The first struct page array
------------------------
linux-2.4.20/arch/um/kernel/physmem.c
157 int init_maps(unsigned long len)
158 {
159         struct page *p, *map;
160         int i, n;
161 
162         n = len >> PAGE_SHIFT;
163         len = n * sizeof(struct page);
164 
165         if(kmalloc_ok){
166                 map = kmalloc(len, GFP_KERNEL);
167                 if(map == NULL) map = vmalloc(len);
168         }
169         else map = alloc_bootmem_low_pages(len);
170 
171         if(map == NULL)
172                 return(-ENOMEM);
173 
174         for(i = 0; i < n; i++){
175                 p = &map[i];
176                 set_page_count(p, 0);
177                 SetPageReserved(p);
178                 INIT_LIST_HEAD(&p->list);
179         }
180 
181         mem_map = map;
182         max_mapnr = n;
183         return(0);
184 }


The second struct page array
-----------------------
mm/memory.c
73 mem_map_t * mem_map; // global define

mm/page_alloc.c
839 void __init free_area_init(unsigned long *zones_size)
840 {
841         free_area_init_core(0, &contig_page_data, &mem_map, zones_size, 0, 0, 0);
842 }

--------
mm/page_alloc.c
685 void __init free_area_init_core(int nid, pg_data_t *pgdat, struct page **gmap,
686         unsigned long *zones_size, unsigned long zone_start_paddr,
687         unsigned long *zholes_size, struct page *lmem_map)
688 {
........
716         map_size = (totalpages + 1)*sizeof(struct page);
717         if (lmem_map == (struct page *)0) {
718                 lmem_map = (struct page *) alloc_bootmem_node(pgdat, map_size);
719                 lmem_map = (struct page *)(PAGE_OFFSET +
720                         MAP_ALIGN((unsigned long)lmem_map - PAGE_OFFSET));
721         }
722         *gmap = pgdat->node_mem_map = lmem_map;


> 
> Thanks,
> //richard
> 
> > Honggang Li (1):
> >   delete unnecessary bootmem struct page array
> > 
> >  arch/um/include/shared/mem_user.h |  2 +-
> >  arch/um/kernel/physmem.c          | 32 ++++++--------------------------
> >  arch/um/kernel/um_arch.c          |  7 +------
> >  3 files changed, 8 insertions(+), 33 deletions(-)
> > 

------------------------------------------------------------------------------
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Re: [PATCH v2] delete unnecessary bootmem struct page array

[Richard Weinberger]

Am 16.06.2014 05:28, schrieb Real Name:
> On Sat, Jun 14, 2014 at 11:44:04AM +0200, Richard Weinberger wrote:
>> Hi!
>>
>> Am 03.06.2014 07:30, schrieb Real Name:
>>> From: Honggang Li <enjoymindful@gmail.com>
>>>
>>> The patch based on linux-next-2014-06-02.
>>>
>>> The old init_maps function does two things:
>>> 1) allocates and initializes one struct page array for bootmem
>>> 2) count the number of total pages
>>>
>>> After removed the source code related to the unnecessary array, the name 
>>> 'init_maps' is some kind of improper named, as it just count the number of
>>> total page numbers. So, I renamed the function as 'mem_total_pages'.
>>>
>>> I tested the patch through repeat reboot the uml kernel many times.
>>> [real@name linux-next]$ make ARCH=um defconfig
>>> [real@name linux-next]$ make ARCH=um linux
>>> [real@name linux-next]$ file linux
>>> linux: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, not stripped
>>> [real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 1
>>> [real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 2
>>> (repeat reboot the uml kernel many times..)
>>
>> Can you please include in the changelog the commit sha1 which made the old init_maps() obsolete?
>> I had a look at the pre-git linux tree, looks like init_maps() wasn't touched for more than 10 years.
> 
> hi, richard
> 
> what is the pre-git linux tree? I searched it with google, but failed.
> 
> The v2.6.12 kernel is the oldest one available from the linux-next git tree. And it has duplicated
> struct page arrays. So, any suggestion how to find the commit you wanted?

https://git.kernel.org/cgit/linux/kernel/git/tglx/history.git

> linux-2.4.20 + uml-patch-2.4.20-8 works on *old* redhat-9 virtual machine. And it seems has duplicated
> struct page array too.
>

And if you remove it here too UML still works?

Thanks,
//richard

> The first struct page array
> ------------------------
> linux-2.4.20/arch/um/kernel/physmem.c
> 157 int init_maps(unsigned long len)
> 158 {
> 159         struct page *p, *map;
> 160         int i, n;
> 161 
> 162         n = len >> PAGE_SHIFT;
> 163         len = n * sizeof(struct page);
> 164 
> 165         if(kmalloc_ok){
> 166                 map = kmalloc(len, GFP_KERNEL);
> 167                 if(map == NULL) map = vmalloc(len);
> 168         }
> 169         else map = alloc_bootmem_low_pages(len);
> 170 
> 171         if(map == NULL)
> 172                 return(-ENOMEM);
> 173 
> 174         for(i = 0; i < n; i++){
> 175                 p = &map[i];
> 176                 set_page_count(p, 0);
> 177                 SetPageReserved(p);
> 178                 INIT_LIST_HEAD(&p->list);
> 179         }
> 180 
> 181         mem_map = map;
> 182         max_mapnr = n;
> 183         return(0);
> 184 }
> 
> 
> The second struct page array
> -----------------------
> mm/memory.c
> 73 mem_map_t * mem_map; // global define
> 
> mm/page_alloc.c
> 839 void __init free_area_init(unsigned long *zones_size)
> 840 {
> 841         free_area_init_core(0, &contig_page_data, &mem_map, zones_size, 0, 0, 0);
> 842 }
> 
> --------
> mm/page_alloc.c
> 685 void __init free_area_init_core(int nid, pg_data_t *pgdat, struct page **gmap,
> 686         unsigned long *zones_size, unsigned long zone_start_paddr,
> 687         unsigned long *zholes_size, struct page *lmem_map)
> 688 {
> ........
> 716         map_size = (totalpages + 1)*sizeof(struct page);
> 717         if (lmem_map == (struct page *)0) {
> 718                 lmem_map = (struct page *) alloc_bootmem_node(pgdat, map_size);
> 719                 lmem_map = (struct page *)(PAGE_OFFSET +
> 720                         MAP_ALIGN((unsigned long)lmem_map - PAGE_OFFSET));
> 721         }
> 722         *gmap = pgdat->node_mem_map = lmem_map;
> 
> 
>>
>> Thanks,
>> //richard
>>
>>> Honggang Li (1):
>>>   delete unnecessary bootmem struct page array
>>>
>>>  arch/um/include/shared/mem_user.h |  2 +-
>>>  arch/um/kernel/physmem.c          | 32 ++++++--------------------------
>>>  arch/um/kernel/um_arch.c          |  7 +------
>>>  3 files changed, 8 insertions(+), 33 deletions(-)
>>>

Re: [PATCH v2] delete unnecessary bootmem struct page array

[Real Name]

[-- Attachment #1: Type: text/plain, Size: 4905 bytes --]

On Mon, Jun 16, 2014 at 08:50:33AM +0200, Richard Weinberger wrote:
> 
> 
> Am 16.06.2014 05:28, schrieb Real Name:
> > On Sat, Jun 14, 2014 at 11:44:04AM +0200, Richard Weinberger wrote:
> >> Hi!
> >>
> >> Am 03.06.2014 07:30, schrieb Real Name:
> >>> From: Honggang Li <enjoymindful@gmail.com>
> >>>
> >>> The patch based on linux-next-2014-06-02.
> >>>
> >>> The old init_maps function does two things:
> >>> 1) allocates and initializes one struct page array for bootmem
> >>> 2) count the number of total pages
> >>>
> >>> After removed the source code related to the unnecessary array, the name 
> >>> 'init_maps' is some kind of improper named, as it just count the number of
> >>> total page numbers. So, I renamed the function as 'mem_total_pages'.
> >>>
> >>> I tested the patch through repeat reboot the uml kernel many times.
> >>> [real@name linux-next]$ make ARCH=um defconfig
> >>> [real@name linux-next]$ make ARCH=um linux
> >>> [real@name linux-next]$ file linux
> >>> linux: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, not stripped
> >>> [real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 1
> >>> [real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 2
> >>> (repeat reboot the uml kernel many times..)
> >>
> >> Can you please include in the changelog the commit sha1 which made the old init_maps() obsolete?
> >> I had a look at the pre-git linux tree, looks like init_maps() wasn't touched for more than 10 years.
> > 
> > hi, richard
> > 
> > what is the pre-git linux tree? I searched it with google, but failed.
> > 
> > The v2.6.12 kernel is the oldest one available from the linux-next git tree. And it has duplicated
> > struct page arrays. So, any suggestion how to find the commit you wanted?
>
 
> https://git.kernel.org/cgit/linux/kernel/git/tglx/history.git

richard, geert, and paul
thanks all of you for the git-pre info.

> 
> > linux-2.4.20 + uml-patch-2.4.20-8 works on *old* redhat-9 virtual machine. And it seems has duplicated
> > struct page array too.
> >
> 
> And if you remove it here too UML still works?

yes, it works. I removed the code related struct page array in init_maps.

Please check the attachments.

[root@rht9 root]# /root/linux-2.4.20/linux ubda=/root/uml/root_fs.rh-7.2-server.pristine.20020312 mem=256m 2>&1 | tee /tmp/log.txt

thanks

> 
> Thanks,
> //richard
> 
> > The first struct page array
> > ------------------------
> > linux-2.4.20/arch/um/kernel/physmem.c
> > 157 int init_maps(unsigned long len)
> > 158 {
> > 159         struct page *p, *map;
> > 160         int i, n;
> > 161 
> > 162         n = len >> PAGE_SHIFT;
> > 163         len = n * sizeof(struct page);
> > 164 
> > 165         if(kmalloc_ok){
> > 166                 map = kmalloc(len, GFP_KERNEL);
> > 167                 if(map == NULL) map = vmalloc(len);
> > 168         }
> > 169         else map = alloc_bootmem_low_pages(len);
> > 170 
> > 171         if(map == NULL)
> > 172                 return(-ENOMEM);
> > 173 
> > 174         for(i = 0; i < n; i++){
> > 175                 p = &map[i];
> > 176                 set_page_count(p, 0);
> > 177                 SetPageReserved(p);
> > 178                 INIT_LIST_HEAD(&p->list);
> > 179         }
> > 180 
> > 181         mem_map = map;
> > 182         max_mapnr = n;
> > 183         return(0);
> > 184 }
> > 
> > 
> > The second struct page array
> > -----------------------
> > mm/memory.c
> > 73 mem_map_t * mem_map; // global define
> > 
> > mm/page_alloc.c
> > 839 void __init free_area_init(unsigned long *zones_size)
> > 840 {
> > 841         free_area_init_core(0, &contig_page_data, &mem_map, zones_size, 0, 0, 0);
> > 842 }
> > 
> > --------
> > mm/page_alloc.c
> > 685 void __init free_area_init_core(int nid, pg_data_t *pgdat, struct page **gmap,
> > 686         unsigned long *zones_size, unsigned long zone_start_paddr,
> > 687         unsigned long *zholes_size, struct page *lmem_map)
> > 688 {
> > ........
> > 716         map_size = (totalpages + 1)*sizeof(struct page);
> > 717         if (lmem_map == (struct page *)0) {
> > 718                 lmem_map = (struct page *) alloc_bootmem_node(pgdat, map_size);
> > 719                 lmem_map = (struct page *)(PAGE_OFFSET +
> > 720                         MAP_ALIGN((unsigned long)lmem_map - PAGE_OFFSET));
> > 721         }
> > 722         *gmap = pgdat->node_mem_map = lmem_map;
> > 
> > 
> >>
> >> Thanks,
> >> //richard
> >>
> >>> Honggang Li (1):
> >>>   delete unnecessary bootmem struct page array
> >>>
> >>>  arch/um/include/shared/mem_user.h |  2 +-
> >>>  arch/um/kernel/physmem.c          | 32 ++++++--------------------------
> >>>  arch/um/kernel/um_arch.c          |  7 +------
> >>>  3 files changed, 8 insertions(+), 33 deletions(-)
> >>>

[-- Attachment #2: linux-2.4.20_uml_init_maps.patch --]
[-- Type: text/x-diff, Size: 628 bytes --]

--- physmem.c.old	2014-06-16 07:35:27.000000000 -0400
+++ physmem.c	2014-06-16 07:40:38.000000000 -0400
@@ -156,29 +156,10 @@
 
 int init_maps(unsigned long len)
 {
-	struct page *p, *map;
-	int i, n;
+	int n;
 
 	n = len >> PAGE_SHIFT;
-	len = n * sizeof(struct page);
 
-	if(kmalloc_ok){
-		map = kmalloc(len, GFP_KERNEL);
-		if(map == NULL) map = vmalloc(len);
-	}
-	else map = alloc_bootmem_low_pages(len);
-
-	if(map == NULL)
-		return(-ENOMEM);
-
-	for(i = 0; i < n; i++){
-		p = &map[i];
-		set_page_count(p, 0);
-		SetPageReserved(p);
-		INIT_LIST_HEAD(&p->list);
-	}
-
-	mem_map = map;
 	max_mapnr = n;
 	return(0);
 }

[-- Attachment #3: log.txt --]
[-- Type: text/plain, Size: 7281 bytes --]

Checking for the skas3 patch in the host...not found
Checking for /proc/mm...not found
Kernel virtual memory size shrunk to 243269632 bytes
Linux version 2.4.20-8um (root@rht9) (gcc version 3.2.2 20030222 (Red Hat Linux 3.2.2-5)) #2 Mon Jun 16 07:41:28 EDT 2014
On node 0 totalpages: 65536
zone(0): 65536 pages.
zone(1): 0 pages.
zone(2): 0 pages.
Kernel command line: ubda=/root/uml/root_fs.rh-7.2-server.pristine.20020312 mem=256m root=/dev/ubd0
Calibrating delay loop... 6829.32 BogoMIPS
Memory: 256152k available
Dentry cache hash table entries: 32768 (order: 6, 262144 bytes)
Inode cache hash table entries: 16384 (order: 5, 131072 bytes)
Mount-cache hash table entries: 4096 (order: 3, 32768 bytes)
Buffer-cache hash table entries: 16384 (order: 4, 65536 bytes)
Page-cache hash table entries: 65536 (order: 6, 262144 bytes)
Checking for host processor cmov support...Yes
Checking for host processor xmm support...No
Checking that ptrace can change system call numbers...OK
Checking that host ptys support output SIGIO...Yes
Checking that host ptys support SIGIO on close...No, enabling workaround
POSIX conformance testing by UNIFIX
Linux NET4.0 for Linux 2.4
Based upon Swansea University Computer Society NET3.039
Initializing RT netlink socket
Starting kswapd
VFS: Diskquotas version dquot_6.4.0 initialized
devfs: v1.12c (20020818) Richard Gooch (rgooch@atnf.csiro.au)
devfs: boot_options: 0x1
JFFS version 1.0, (C) 1999, 2000  Axis Communications AB
JFFS2 version 2.1. (C) 2001 Red Hat, Inc., designed by Axis Communications AB.
pty: 256 Unix98 ptys configured
SLIP: version 0.8.4-NET3.019-NEWTTY (dynamic channels, max=256).
RAMDISK driver initialized: 16 RAM disks of 4096K size 1024 blocksize
loop: loaded (max 8 devices)
PPP generic driver version 2.4.2
Universal TUN/TAP device driver 1.5 (C)1999-2002 Maxim Krasnyansky
SCSI subsystem driver Revision: 1.00
scsi0 : scsi_debug, Version: 0.61 (20020815), num_devs=1, dev_size_mb=8, opts=0x0
  Vendor: Linux     Model: scsi_debug        Rev: 0004
  Type:   Direct-Access                      ANSI SCSI revision: 03
blkmtd: error, missing `device' name
Initializing software serial port version 1
mconsole (version 2) initialized on /root/.uml/rdspmA/mconsole
Partition check:
 ubda: unknown partition table
UML Audio Relay (host dsp = /dev/sound/dsp, host mixer = /dev/sound/mixer)
Initializing stdio console driver
NET4: Linux TCP/IP 1.0 for NET4.0
IP Protocols: ICMP, UDP, TCP
IP: routing cache hash table of 2048 buckets, 16Kbytes
TCP: Hash tables configured (established 16384 bind 32768)
NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
VFS: Mounted root (ext2 filesystem) readonly.
Mounted devfs on /dev
\rINIT: version 2.78 booting
			Welcome to Red Hat Linux
		Press 'I' to enter interactive startup.
Mounting proc filesystem:  [  OK  ]
Configuring kernel parameters:  [  OK  ]
Setting clock : Mon Jun 16 08:02:25 EDT 2014 [  OK  ]
Activating swap partitions:  [  OK  ]
Setting hostname redhat72.goober.org:  [  OK  ]
Checking root filesystem
/dev/ubd/0: clean, 38751/64768 files, 212070/259072 blocks
[/sbin/fsck.ext2 (1) -- /] fsck.ext2 -a /dev/ubd/0 
[  OK  ]
Remounting root filesystem in read-write mode:  [  OK  ]
Finding module dependencies:  depmod: cannot read ELF header from /lib/modules/2.4.20-8um/modules.dep
depmod: cannot read ELF header from /lib/modules/2.4.20-8um/modules.generic_string
depmod: /lib/modules/2.4.20-8um/modules.ieee1394map is not an ELF file
depmod: /lib/modules/2.4.20-8um/modules.isapnpmap is not an ELF file
depmod: cannot read ELF header from /lib/modules/2.4.20-8um/modules.parportmap
depmod: /lib/modules/2.4.20-8um/modules.pcimap is not an ELF file
depmod: cannot read ELF header from /lib/modules/2.4.20-8um/modules.pnpbiosmap
depmod: /lib/modules/2.4.20-8um/modules.usbmap is not an ELF file
[FAILED]
Checking filesystems
Checking all file systems.
[  OK  ]
Mounting local filesystems:  [  OK  ]
Enabling local filesystem quotas:  [  OK  ]
swapon: cannot stat /dev/ubd/1: No such file or directory
Enabling swap space:  [  OK  ]
\rINIT: Entering runlevel: 3
Entering non-interactive startup
Setting network parameters:  [  OK  ]
Bringing up interface lo:  [  OK  ]
SIOCADDRT: No such device
SIOCADDRT: Network is unreachable
Starting system logger: [  OK  ]
Starting kernel logger: [  OK  ]
Starting portmapper: [  OK  ]
Initializing random number generator:  [  OK  ]
Mounting other filesystems:  [  OK  ]
Starting identd: [  OK  ]
Starting snmpd: [  OK  ]
Starting named: [  OK  ]
Starting sshd:  [  OK  ]
Starting xinetd: [  OK  ]
Starting sendmail: [  OK  ]
Starting httpd: [  OK  ]
Starting crond: [  OK  ]
Starting squid:  [  OK  ]
Starting SMB services: [  OK  ]
Starting NMB services: [  OK  ]
Please run makehistory and/or makedbz before starting innd.
Running Linuxconf hooks:  [  OK  ]
^[c
Unauthorized access to this system is strictly prohibited.
redhat72 login: Warning: This program is an suid-root program or is being run by the root user.
The full text of the error or warning message cannot be safely formatted
in this environment. You may get a more descriptive message by running the
program as a non-root user or by removing the suid bit on the executable.
xterm Xt error: Can't open display: %s
Warning: This program is an suid-root program or is being run by the root user.
The full text of the error or warning message cannot be safely formatted
in this environment. You may get a more descriptive message by running the
program as a non-root user or by removing the suid bit on the executable.
xterm Xt error: Can't open display: %s


Unauthorized access to this system is strictly prohibited.
redhat72 login: 

Unauthorized access to this system is strictly prohibited.
redhat72 login: root
Password: 
Last login: Mon Jun 16 08:00:06 on vc/0
bash-2.05# /sbin/poweroff 
\a
Broadcast message from root (vc/0) Mon Jun 16 08:03:17 2014...

\rThe system is going down for system halt NOW !!
\rINIT: Switching to runlevel: 0
\rINIT: Sending processes the TERM signal
bash-2.05# \rINIT: Sending processes the KILL signal
\rINIT: Pid 527 [id 1] seems to hang
\rINIT: Pid 528 [id 2] seems to hang
Stopping httpd: [  OK  ]
Stopping squid:  [  OK  ]
Stopping sshd:[  OK  ]
Shutting down sendmail: [  OK  ]
Shutting down SMB services: [  OK  ]
Shutting down NMB services: [FAILED]
Stopping named: [  OK  ]
Stopping snmpd: [  OK  ]
Stopping xinetd: [  OK  ]
Stopping crond: [  OK  ]
Stopping identd: [  OK  ]
Saving random seed:  [  OK  ]
Stopping portmapper: [  OK  ]
Shutting down kernel logger: [  OK  ]
Shutting down system logger: [  OK  ]
Starting killall:  Shutting down SMB services: [FAILED]
Shutting down NMB services: [FAILED]
[FAILED]
Sending all processes the TERM signal... 
Sending all processes the KILL signal... 
Syncing hardware clock to system time 
Turning off quotas:  
umount2: Device or resource busy
umount: devfs: not found
umount: /dev: Illegal seek
Halting system...
Power down.
tracing thread pid = 11409


[-- Attachment #4: init_maps.s --]
[-- Type: text/plain, Size: 1581 bytes --]

[root@rht9 linux-2.4.20]# objdump -S -d linux > linux_source.s
[root@rht9 linux-2.4.20]# vim linux_source.s	
	 472789 a00d7acc <to_phys>:
	 472790 a00d7acc:       55                      push   %ebp
	 472791 a00d7acd:       89 e5                   mov    %esp,%ebp
	 472792 a00d7acf:       8b 45 08                mov    0x8(%ebp),%eax
	 472793 a00d7ad2:       2b 05 e0 60 25 a0       sub    0xa02560e0,%eax
	 472794 a00d7ad8:       c9                      leave
	 472795 a00d7ad9:       c3                      ret
	 472796 a00d7ada:       89 f6                   mov    %esi,%esi
	 472797
	 472798 a00d7adc <init_maps>:
	 472799 a00d7adc:       55                      push   %ebp
	 472800 a00d7add:       89 e5                   mov    %esp,%ebp
	 472801 a00d7adf:       8b 45 08                mov    0x8(%ebp),%eax
	 472802 a00d7ae2:       c1 e8 0c                shr    $0xc,%eax
	 472803 a00d7ae5:       a3 e0 43 23 a0          mov    %eax,0xa02343e0
	 472804 a00d7aea:       31 c0                   xor    %eax,%eax
	 472805 a00d7aec:       c9                      leave
	 472806 a00d7aed:       c3                      ret
	 472807 a00d7aee:       89 f6                   mov    %esi,%esi
	 472808
	 472809 a00d7af0 <__virt_to_page>:
	 472810 a00d7af0:       55                      push   %ebp
	 472811 a00d7af1:       89 e5                   mov    %esp,%ebp
	 472812 a00d7af3:       8b 55 08                mov    0x8(%ebp),%edx
	 472813 a00d7af6:       2b 15 e0 60 25 a0       sub    0xa02560e0,%edx
	 472814 a00d7afc:       c1 ea 0c                shr    $0xc,%edx
	

[-- Attachment #5: bash_history_tail.txt --]
[-- Type: text/plain, Size: 2633 bytes --]

[root@rht9 root]# 
[root@rht9 root]# uname -a
Linux rht9 2.4.25 #2 SMP Mon Jun 9 03:21:50 EDT 2014 i686 i686 i386 GNU/Linux



Unauthorized access to this system is strictly prohibited.
redhat72 login: Warning: This program is an suid-root program or is being run by the root user.
The full text of the error or warning message cannot be safely formatted
in this environment. You may get a more descriptive message by running the
program as a non-root user or by removing the suid bit on the executable.
xterm Xt error: Can't open display: %s
Warning: This program is an suid-root program or is being run by the root user.
The full text of the error or warning message cannot be safely formatted
in this environment. You may get a more descriptive message by running the
program as a non-root user or by removing the suid bit on the executable.
xterm Xt error: Can't open display: %s


Unauthorized access to this system is strictly prohibited.
redhat72 login: 

Unauthorized access to this system is strictly prohibited.
redhat72 login: root
Password: 
Last login: Mon Jun 16 07:56:47 on vc/0
bash-2.05#       
bash-2.05# 
bash-2.05# 
bash-2.05# cat /proc/cpuinfo 
processor  : 0
vendor_id  : User Mode Linux
model name : UML
mode  	   : tt
host	     : Linux rht9 2.4.25 #2 SMP Mon Jun 9 03:21:50 EDT 2014 i686
bogomips     : 6816.66

bash-2.05# 
bash-2.05# 
bash-2.05# uname -a
Linux redhat72.goober.org 2.4.20-8um #2 Mon Jun 16 07:41:28 EDT 2014 i686 unknown
bash-2.05# 
bash-2.05# 
bash-2.05# /sbin/poweroff 

Broadcast message from root (vc/0) Mon Jun 16 08:00:23 2014...

The system is going down for system halt NOW !!
INIT: Switching to runlevel: 0
INIT: Sending processes the TERM signal
INIT: Sending processes the KILL signal
INIT: Pid 520 [id 1] seems to hang
INIT: Pid 521 [id 2] seems to hang
Stopping httpd: [  OK  ]
Stopping squid:  [  OK  ]
Stopping sshd:[  OK  ]
Shutting down sendmail: [  OK  ]
Shutting down SMB services: [  OK  ]
Shutting down NMB services: [FAILED]
Stopping named: [  OK  ]
Stopping snmpd: [  OK  ]
Stopping xinetd: [  OK  ]
Stopping crond: [  OK  ]
Stopping identd: [  OK  ]
Saving random seed:  [  OK  ]
Stopping portmapper: [  OK  ]
Shutting down kernel logger: [  OK  ]
Shutting down system logger: [  OK  ]
Starting killall:  Shutting down SMB services: [FAILED]
Shutting down NMB services: [FAILED]
[FAILED]
Sending all processes the TERM signal... 
Sending all processes the KILL signal... 
Syncing hardware clock to system time 
Turning off quotas:  
umount2: Device or resource busy
umount: devfs: not found
umount: /dev: Illegal seek
Halting system...
Power down.

[root@rht9 root]# 

Re: [PATCH v2] delete unnecessary bootmem struct page array

[Real Name]

On Mon, Jun 16, 2014 at 04:12:38PM +0800, Real Name wrote:
> On Mon, Jun 16, 2014 at 08:50:33AM +0200, Richard Weinberger wrote:
> > 
> > 
> > Am 16.06.2014 05:28, schrieb Real Name:
> > > On Sat, Jun 14, 2014 at 11:44:04AM +0200, Richard Weinberger wrote:
> > >> Hi!
> > >>
> > >> Am 03.06.2014 07:30, schrieb Real Name:
> > >>> From: Honggang Li <enjoymindful@gmail.com>
> > >>>
> > >>> The patch based on linux-next-2014-06-02.
> > >>>
> > >>> The old init_maps function does two things:
> > >>> 1) allocates and initializes one struct page array for bootmem
> > >>> 2) count the number of total pages
> > >>>
> > >>> After removed the source code related to the unnecessary array, the name 
> > >>> 'init_maps' is some kind of improper named, as it just count the number of
> > >>> total page numbers. So, I renamed the function as 'mem_total_pages'.
> > >>>
> > >>> I tested the patch through repeat reboot the uml kernel many times.
> > >>> [real@name linux-next]$ make ARCH=um defconfig
> > >>> [real@name linux-next]$ make ARCH=um linux
> > >>> [real@name linux-next]$ file linux
> > >>> linux: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, not stripped
> > >>> [real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 1
> > >>> [real@name linux-next]$ ./linux ubda=/home/real/linux-next/Fedora20-AMD64-root_fs mem=256m && sync && echo 2
> > >>> (repeat reboot the uml kernel many times..)
> > >>
> > >> Can you please include in the changelog the commit sha1 which made the old init_maps() obsolete?

I think we need find out which commit deleted the line "mem_map = map;" in init_maps function.

> > >> I had a look at the pre-git linux tree, looks like init_maps() wasn't touched for more than 10 years.
> > > 
> > > hi, richard
> > > 
> > > what is the pre-git linux tree? I searched it with google, but failed.
> > > 
> > > The v2.6.12 kernel is the oldest one available from the linux-next git tree. And it has duplicated
> > > struct page arrays. So, any suggestion how to find the commit you wanted?
> >
>  
> > https://git.kernel.org/cgit/linux/kernel/git/tglx/history.git
> 
> richard, geert, and paul
> thanks all of you for the git-pre info.
> 
> > 
> > > linux-2.4.20 + uml-patch-2.4.20-8 works on *old* redhat-9 virtual machine. And it seems has duplicated
> > > struct page array too.
> > >
> > 
> > And if you remove it here too UML still works?
> 
> yes, it works. I removed the code related struct page array in init_maps.
> 
> Please check the attachments.
> 
> [root@rht9 root]# /root/linux-2.4.20/linux ubda=/root/uml/root_fs.rh-7.2-server.pristine.20020312 mem=256m 2>&1 | tee /tmp/log.txt
> 
> thanks
> 
> > 
> > Thanks,
> > //richard
> > 
> > > The first struct page array
> > > ------------------------
> > > linux-2.4.20/arch/um/kernel/physmem.c
> > > 157 int init_maps(unsigned long len)
> > > 158 {
> > > 159         struct page *p, *map;
> > > 160         int i, n;
> > > 161 
> > > 162         n = len >> PAGE_SHIFT;
> > > 163         len = n * sizeof(struct page);
> > > 164 
> > > 165         if(kmalloc_ok){
> > > 166                 map = kmalloc(len, GFP_KERNEL);
> > > 167                 if(map == NULL) map = vmalloc(len);
> > > 168         }
> > > 169         else map = alloc_bootmem_low_pages(len);
> > > 170 
> > > 171         if(map == NULL)
> > > 172                 return(-ENOMEM);
> > > 173 
> > > 174         for(i = 0; i < n; i++){
> > > 175                 p = &map[i];
> > > 176                 set_page_count(p, 0);
> > > 177                 SetPageReserved(p);
> > > 178                 INIT_LIST_HEAD(&p->list);
> > > 179         }
> > > 180 
> > > 181         mem_map = map;
> > > 182         max_mapnr = n;
> > > 183         return(0);
> > > 184 }
> > > 
> > > 
> > > The second struct page array
> > > -----------------------
> > > mm/memory.c
> > > 73 mem_map_t * mem_map; // global define
> > > 
> > > mm/page_alloc.c
> > > 839 void __init free_area_init(unsigned long *zones_size)
> > > 840 {
> > > 841         free_area_init_core(0, &contig_page_data, &mem_map, zones_size, 0, 0, 0);
> > > 842 }
> > > 
> > > --------
> > > mm/page_alloc.c
> > > 685 void __init free_area_init_core(int nid, pg_data_t *pgdat, struct page **gmap,
> > > 686         unsigned long *zones_size, unsigned long zone_start_paddr,
> > > 687         unsigned long *zholes_size, struct page *lmem_map)
> > > 688 {
> > > ........
> > > 716         map_size = (totalpages + 1)*sizeof(struct page);
> > > 717         if (lmem_map == (struct page *)0) {
> > > 718                 lmem_map = (struct page *) alloc_bootmem_node(pgdat, map_size);
> > > 719                 lmem_map = (struct page *)(PAGE_OFFSET +
> > > 720                         MAP_ALIGN((unsigned long)lmem_map - PAGE_OFFSET));
> > > 721         }
> > > 722         *gmap = pgdat->node_mem_map = lmem_map;
> > > 
> > > 
> > >>
> > >> Thanks,
> > >> //richard
> > >>
> > >>> Honggang Li (1):
> > >>>   delete unnecessary bootmem struct page array
> > >>>
> > >>>  arch/um/include/shared/mem_user.h |  2 +-
> > >>>  arch/um/kernel/physmem.c          | 32 ++++++--------------------------
> > >>>  arch/um/kernel/um_arch.c          |  7 +------
> > >>>  3 files changed, 8 insertions(+), 33 deletions(-)
> > >>>

> --- physmem.c.old	2014-06-16 07:35:27.000000000 -0400
> +++ physmem.c	2014-06-16 07:40:38.000000000 -0400
> @@ -156,29 +156,10 @@
>  
>  int init_maps(unsigned long len)
>  {
> -	struct page *p, *map;
> -	int i, n;
> +	int n;
>  
>  	n = len >> PAGE_SHIFT;
> -	len = n * sizeof(struct page);
>  
> -	if(kmalloc_ok){
> -		map = kmalloc(len, GFP_KERNEL);
> -		if(map == NULL) map = vmalloc(len);
> -	}
> -	else map = alloc_bootmem_low_pages(len);
> -
> -	if(map == NULL)
> -		return(-ENOMEM);
> -
> -	for(i = 0; i < n; i++){
> -		p = &map[i];
> -		set_page_count(p, 0);
> -		SetPageReserved(p);
> -		INIT_LIST_HEAD(&p->list);
> -	}
> -
> -	mem_map = map;
>  	max_mapnr = n;
>  	return(0);
>  }

> Checking for the skas3 patch in the host...not found
> Checking for /proc/mm...not found
> Kernel virtual memory size shrunk to 243269632 bytes
> Linux version 2.4.20-8um (root@rht9) (gcc version 3.2.2 20030222 (Red Hat Linux 3.2.2-5)) #2 Mon Jun 16 07:41:28 EDT 2014
> On node 0 totalpages: 65536
> zone(0): 65536 pages.
> zone(1): 0 pages.
> zone(2): 0 pages.
> Kernel command line: ubda=/root/uml/root_fs.rh-7.2-server.pristine.20020312 mem=256m root=/dev/ubd0
> Calibrating delay loop... 6829.32 BogoMIPS
> Memory: 256152k available
> Dentry cache hash table entries: 32768 (order: 6, 262144 bytes)
> Inode cache hash table entries: 16384 (order: 5, 131072 bytes)
> Mount-cache hash table entries: 4096 (order: 3, 32768 bytes)
> Buffer-cache hash table entries: 16384 (order: 4, 65536 bytes)
> Page-cache hash table entries: 65536 (order: 6, 262144 bytes)
> Checking for host processor cmov support...Yes
> Checking for host processor xmm support...No
> Checking that ptrace can change system call numbers...OK
> Checking that host ptys support output SIGIO...Yes
> Checking that host ptys support SIGIO on close...No, enabling workaround
> POSIX conformance testing by UNIFIX
> Linux NET4.0 for Linux 2.4
> Based upon Swansea University Computer Society NET3.039
> Initializing RT netlink socket
> Starting kswapd
> VFS: Diskquotas version dquot_6.4.0 initialized
> devfs: v1.12c (20020818) Richard Gooch (rgooch@atnf.csiro.au)
> devfs: boot_options: 0x1
> JFFS version 1.0, (C) 1999, 2000  Axis Communications AB
> JFFS2 version 2.1. (C) 2001 Red Hat, Inc., designed by Axis Communications AB.
> pty: 256 Unix98 ptys configured
> SLIP: version 0.8.4-NET3.019-NEWTTY (dynamic channels, max=256).
> RAMDISK driver initialized: 16 RAM disks of 4096K size 1024 blocksize
> loop: loaded (max 8 devices)
> PPP generic driver version 2.4.2
> Universal TUN/TAP device driver 1.5 (C)1999-2002 Maxim Krasnyansky
> SCSI subsystem driver Revision: 1.00
> scsi0 : scsi_debug, Version: 0.61 (20020815), num_devs=1, dev_size_mb=8, opts=0x0
>   Vendor: Linux     Model: scsi_debug        Rev: 0004
>   Type:   Direct-Access                      ANSI SCSI revision: 03
> blkmtd: error, missing `device' name
> Initializing software serial port version 1
> mconsole (version 2) initialized on /root/.uml/rdspmA/mconsole
> Partition check:
>  ubda: unknown partition table
> UML Audio Relay (host dsp = /dev/sound/dsp, host mixer = /dev/sound/mixer)
> Initializing stdio console driver
> NET4: Linux TCP/IP 1.0 for NET4.0
> IP Protocols: ICMP, UDP, TCP
> IP: routing cache hash table of 2048 buckets, 16Kbytes
> TCP: Hash tables configured (established 16384 bind 32768)
> NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
> VFS: Mounted root (ext2 filesystem) readonly.
> Mounted devfs on /dev
> 
INIT: version 2.78 booting
> 			Welcome to Red Hat Linux
> 		Press 'I' to enter interactive startup.
> Mounting proc filesystem:  [  OK  ]
> Configuring kernel parameters:  [  OK  ]
> Setting clock : Mon Jun 16 08:02:25 EDT 2014 [  OK  ]
> Activating swap partitions:  [  OK  ]
> Setting hostname redhat72.goober.org:  [  OK  ]
> Checking root filesystem
> /dev/ubd/0: clean, 38751/64768 files, 212070/259072 blocks
> [/sbin/fsck.ext2 (1) -- /] fsck.ext2 -a /dev/ubd/0 
> [  OK  ]
> Remounting root filesystem in read-write mode:  [  OK  ]
> Finding module dependencies:  depmod: cannot read ELF header from /lib/modules/2.4.20-8um/modules.dep
> depmod: cannot read ELF header from /lib/modules/2.4.20-8um/modules.generic_string
> depmod: /lib/modules/2.4.20-8um/modules.ieee1394map is not an ELF file
> depmod: /lib/modules/2.4.20-8um/modules.isapnpmap is not an ELF file
> depmod: cannot read ELF header from /lib/modules/2.4.20-8um/modules.parportmap
> depmod: /lib/modules/2.4.20-8um/modules.pcimap is not an ELF file
> depmod: cannot read ELF header from /lib/modules/2.4.20-8um/modules.pnpbiosmap
> depmod: /lib/modules/2.4.20-8um/modules.usbmap is not an ELF file
> [FAILED]
> Checking filesystems
> Checking all file systems.
> [  OK  ]
> Mounting local filesystems:  [  OK  ]
> Enabling local filesystem quotas:  [  OK  ]
> swapon: cannot stat /dev/ubd/1: No such file or directory
> Enabling swap space:  [  OK  ]
> 
INIT: Entering runlevel: 3
> Entering non-interactive startup
> Setting network parameters:  [  OK  ]
> Bringing up interface lo:  [  OK  ]
> SIOCADDRT: No such device
> SIOCADDRT: Network is unreachable
> Starting system logger: [  OK  ]
> Starting kernel logger: [  OK  ]
> Starting portmapper: [  OK  ]
> Initializing random number generator:  [  OK  ]
> Mounting other filesystems:  [  OK  ]
> Starting identd: [  OK  ]
> Starting snmpd: [  OK  ]
> Starting named: [  OK  ]
> Starting sshd:  [  OK  ]
> Starting xinetd: [  OK  ]
> Starting sendmail: [  OK  ]
> Starting httpd: [  OK  ]
> Starting crond: [  OK  ]
> Starting squid:  [  OK  ]
> Starting SMB services: [  OK  ]
> Starting NMB services: [  OK  ]
> Please run makehistory and/or makedbz before starting innd.
> Running Linuxconf hooks:  [  OK  ]
> ^[c
> Unauthorized access to this system is strictly prohibited.
> redhat72 login: Warning: This program is an suid-root program or is being run by the root user.
> The full text of the error or warning message cannot be safely formatted
> in this environment. You may get a more descriptive message by running the
> program as a non-root user or by removing the suid bit on the executable.
> xterm Xt error: Can't open display: %s
> Warning: This program is an suid-root program or is being run by the root user.
> The full text of the error or warning message cannot be safely formatted
> in this environment. You may get a more descriptive message by running the
> program as a non-root user or by removing the suid bit on the executable.
> xterm Xt error: Can't open display: %s
> 
> 
> Unauthorized access to this system is strictly prohibited.
> redhat72 login: 
> 
> Unauthorized access to this system is strictly prohibited.
> redhat72 login: root
> Password: 
> Last login: Mon Jun 16 08:00:06 on vc/0
> bash-2.05# /sbin/poweroff 
> \a
> Broadcast message from root (vc/0) Mon Jun 16 08:03:17 2014...
> 
> 
The system is going down for system halt NOW !!
> 
INIT: Switching to runlevel: 0
> 
INIT: Sending processes the TERM signal
> bash-2.05# 
INIT: Sending processes the KILL signal
> 
INIT: Pid 527 [id 1] seems to hang
> 
INIT: Pid 528 [id 2] seems to hang
> Stopping httpd: [  OK  ]
> Stopping squid:  [  OK  ]
> Stopping sshd:[  OK  ]
> Shutting down sendmail: [  OK  ]
> Shutting down SMB services: [  OK  ]
> Shutting down NMB services: [FAILED]
> Stopping named: [  OK  ]
> Stopping snmpd: [  OK  ]
> Stopping xinetd: [  OK  ]
> Stopping crond: [  OK  ]
> Stopping identd: [  OK  ]
> Saving random seed:  [  OK  ]
> Stopping portmapper: [  OK  ]
> Shutting down kernel logger: [  OK  ]
> Shutting down system logger: [  OK  ]
> Starting killall:  Shutting down SMB services: [FAILED]
> Shutting down NMB services: [FAILED]
> [FAILED]
> Sending all processes the TERM signal... 
> Sending all processes the KILL signal... 
> Syncing hardware clock to system time 
> Turning off quotas:  
> umount2: Device or resource busy
> umount: devfs: not found
> umount: /dev: Illegal seek
> Halting system...
> Power down.
> tracing thread pid = 11409
> 

> [root@rht9 linux-2.4.20]# objdump -S -d linux > linux_source.s
> [root@rht9 linux-2.4.20]# vim linux_source.s	
> 	 472789 a00d7acc <to_phys>:
> 	 472790 a00d7acc:       55                      push   %ebp
> 	 472791 a00d7acd:       89 e5                   mov    %esp,%ebp
> 	 472792 a00d7acf:       8b 45 08                mov    0x8(%ebp),%eax
> 	 472793 a00d7ad2:       2b 05 e0 60 25 a0       sub    0xa02560e0,%eax
> 	 472794 a00d7ad8:       c9                      leave
> 	 472795 a00d7ad9:       c3                      ret
> 	 472796 a00d7ada:       89 f6                   mov    %esi,%esi
> 	 472797
> 	 472798 a00d7adc <init_maps>:
> 	 472799 a00d7adc:       55                      push   %ebp
> 	 472800 a00d7add:       89 e5                   mov    %esp,%ebp
> 	 472801 a00d7adf:       8b 45 08                mov    0x8(%ebp),%eax
> 	 472802 a00d7ae2:       c1 e8 0c                shr    $0xc,%eax
> 	 472803 a00d7ae5:       a3 e0 43 23 a0          mov    %eax,0xa02343e0
> 	 472804 a00d7aea:       31 c0                   xor    %eax,%eax
> 	 472805 a00d7aec:       c9                      leave
> 	 472806 a00d7aed:       c3                      ret
> 	 472807 a00d7aee:       89 f6                   mov    %esi,%esi
> 	 472808
> 	 472809 a00d7af0 <__virt_to_page>:
> 	 472810 a00d7af0:       55                      push   %ebp
> 	 472811 a00d7af1:       89 e5                   mov    %esp,%ebp
> 	 472812 a00d7af3:       8b 55 08                mov    0x8(%ebp),%edx
> 	 472813 a00d7af6:       2b 15 e0 60 25 a0       sub    0xa02560e0,%edx
> 	 472814 a00d7afc:       c1 ea 0c                shr    $0xc,%edx
> 	

> [root@rht9 root]# 
> [root@rht9 root]# uname -a
> Linux rht9 2.4.25 #2 SMP Mon Jun 9 03:21:50 EDT 2014 i686 i686 i386 GNU/Linux
> 
> 
> 
> Unauthorized access to this system is strictly prohibited.
> redhat72 login: Warning: This program is an suid-root program or is being run by the root user.
> The full text of the error or warning message cannot be safely formatted
> in this environment. You may get a more descriptive message by running the
> program as a non-root user or by removing the suid bit on the executable.
> xterm Xt error: Can't open display: %s
> Warning: This program is an suid-root program or is being run by the root user.
> The full text of the error or warning message cannot be safely formatted
> in this environment. You may get a more descriptive message by running the
> program as a non-root user or by removing the suid bit on the executable.
> xterm Xt error: Can't open display: %s
> 
> 
> Unauthorized access to this system is strictly prohibited.
> redhat72 login: 
> 
> Unauthorized access to this system is strictly prohibited.
> redhat72 login: root
> Password: 
> Last login: Mon Jun 16 07:56:47 on vc/0
> bash-2.05#       
> bash-2.05# 
> bash-2.05# 
> bash-2.05# cat /proc/cpuinfo 
> processor  : 0
> vendor_id  : User Mode Linux
> model name : UML
> mode  	   : tt
> host	     : Linux rht9 2.4.25 #2 SMP Mon Jun 9 03:21:50 EDT 2014 i686
> bogomips     : 6816.66
> 
> bash-2.05# 
> bash-2.05# 
> bash-2.05# uname -a
> Linux redhat72.goober.org 2.4.20-8um #2 Mon Jun 16 07:41:28 EDT 2014 i686 unknown
> bash-2.05# 
> bash-2.05# 
> bash-2.05# /sbin/poweroff 
> 
> Broadcast message from root (vc/0) Mon Jun 16 08:00:23 2014...
> 
> The system is going down for system halt NOW !!
> INIT: Switching to runlevel: 0
> INIT: Sending processes the TERM signal
> INIT: Sending processes the KILL signal
> INIT: Pid 520 [id 1] seems to hang
> INIT: Pid 521 [id 2] seems to hang
> Stopping httpd: [  OK  ]
> Stopping squid:  [  OK  ]
> Stopping sshd:[  OK  ]
> Shutting down sendmail: [  OK  ]
> Shutting down SMB services: [  OK  ]
> Shutting down NMB services: [FAILED]
> Stopping named: [  OK  ]
> Stopping snmpd: [  OK  ]
> Stopping xinetd: [  OK  ]
> Stopping crond: [  OK  ]
> Stopping identd: [  OK  ]
> Saving random seed:  [  OK  ]
> Stopping portmapper: [  OK  ]
> Shutting down kernel logger: [  OK  ]
> Shutting down system logger: [  OK  ]
> Starting killall:  Shutting down SMB services: [FAILED]
> Shutting down NMB services: [FAILED]
> [FAILED]
> Sending all processes the TERM signal... 
> Sending all processes the KILL signal... 
> Syncing hardware clock to system time 
> Turning off quotas:  
> umount2: Device or resource busy
> umount: devfs: not found
> umount: /dev: Illegal seek
> Halting system...
> Power down.
> 
> [root@rht9 root]# 

Re: [PATCH v2] delete unnecessary bootmem struct page array

[Geert Uytterhoeven]

On Mon, Jun 16, 2014 at 10:28 AM, Real Name <enjoymindful@gmail.com> wrote:
>> > >> Can you please include in the changelog the commit sha1 which made the old init_maps() obsolete?
>
> I think we need find out which commit deleted the line "mem_map = map;" in init_maps function.

marc.info/?l=linux-kernel&m=111024122220474&w=2

v2.6.12-rc1

commit 5678d7fc97ac75f7401ce77897773cc0bb3afee5
Author: Dave Hansen <haveblue@us.ibm.com>
Date:   Sun Mar 13 00:22:56 2005 -0800

    [PATCH] no arch-specific mem_map init

    So, this patch started out with me trying to keep from passing contiguous,
    node-specific mem_map into free_area_init_node() and cousins.  Instead, I
    relied on some calls to pfn_to_page().

    This works fine and dandy when all you need is the pgdat->node_mem_map to
    do pfn_to_page().  However, the non-NUMA/DISCONTIG architectures use the
    real, global mem_map[] instead of a node_mem_map in the pfn_to_page()
    calculation.  So, I ended up effectively trying to initialize mem_map from
    itself, when it was NULL.  That was bad, and caused some very pretty colors
    on someone's screen when he tested it.

    So, I had to make sure to initialize the global mem_map[] before calling
    into free_area_init_node().  Then, I realized how many architectures do
    this on their own, and have comments like this:

            /* XXX: MRB-remove - this doesn't seem sane, should this be done som
            mem_map = NODE_DATA(0)->node_mem_map;

    The following patch does what my first one did (don't pass mem_map into the
    init functions), incorporates Jesse Barnes' ia64 fixes on top of that, and
    gets rid of all but one of the global mem_map initializations (parisc is
    weird).  It also magically removes more code than it adds.  It could be
    smaller, but I shamelessly added some comments.

    Boot-tested on ppc64, i386 (NUMAQ, plain SMP, laptop), UML (i386).

    Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
    Signed-off-by: Andrew Morton <akpm@osdl.org>
    Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v2] delete unnecessary bootmem struct page array

[Real Name]

[-- Attachment #1: Type: text/plain, Size: 721 bytes --]

On Mon, Jun 16, 2014 at 11:15:23AM +0200, Geert Uytterhoeven wrote:
> On Mon, Jun 16, 2014 at 10:28 AM, Real Name <enjoymindful@gmail.com> wrote:
> >> > >> Can you please include in the changelog the commit sha1 which made the old init_maps() obsolete?

hi,

The commit sha1 had been included as required. Please review the attached patch. 
I only update the changlog of the patch.

thanks
> >
> > I think we need find out which commit deleted the line "mem_map = map;" in init_maps function.
> 
> 
> v2.6.12-rc1
> 
> commit 5678d7fc97ac75f7401ce77897773cc0bb3afee5

Geert, thank you.

> Author: Dave Hansen <haveblue@us.ibm.com>
> Date:   Sun Mar 13 00:22:56 2005 -0800
> 
>     [PATCH] no arch-specific mem_map init
> 

[-- Attachment #2: 0001-UML-delete-unnecessary-bootmem-struct-page-array.patch --]
[-- Type: text/x-diff, Size: 3817 bytes --]

>From 29e5e83f8f3988ea1396d61b4d5764e7904f82c5 Mon Sep 17 00:00:00 2001
From: Honggang Li <enjoymindful@gmail.com>
Date: Mon, 16 Jun 2014 18:05:47 +0800
Subject: [PATCH] UML delete unnecessary bootmem struct page array

1) uml kernel bootmem managed through bootmem_data->node_bootmem_map,
not the struct page array, so the array is unnecessary.

2) the bootmem struct page array has been pointed by a *local* pointer,
struct page *map, in init_maps function. The array can be accessed only
in init_maps's scope. As a result, uml kernel wastes about 1% of total
memory.

3) commit 5678d7fc97ac75f7401ce77897773cc0bb3afee5 obsoleted
the init_maps function.

Signed-off-by: Honggang Li <enjoymindful@gmail.com>
---
 arch/um/include/shared/mem_user.h |  2 +-
 arch/um/kernel/physmem.c          | 32 ++++++--------------------------
 arch/um/kernel/um_arch.c          |  7 +------
 3 files changed, 8 insertions(+), 33 deletions(-)

diff --git a/arch/um/include/shared/mem_user.h b/arch/um/include/shared/mem_user.h
index 46384ac..cb84414 100644
--- a/arch/um/include/shared/mem_user.h
+++ b/arch/um/include/shared/mem_user.h
@@ -49,7 +49,7 @@ extern int iomem_size;
 extern int init_mem_user(void);
 extern void setup_memory(void *entry);
 extern unsigned long find_iomem(char *driver, unsigned long *len_out);
-extern int init_maps(unsigned long physmem, unsigned long iomem,
+extern void mem_total_pages(unsigned long physmem, unsigned long iomem,
 		     unsigned long highmem);
 extern unsigned long get_vm(unsigned long len);
 extern void setup_physmem(unsigned long start, unsigned long usable,
diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c
index 30fdd5d..549ecf3 100644
--- a/arch/um/kernel/physmem.c
+++ b/arch/um/kernel/physmem.c
@@ -22,39 +22,19 @@ EXPORT_SYMBOL(high_physmem);
 
 extern unsigned long long physmem_size;
 
-int __init init_maps(unsigned long physmem, unsigned long iomem,
+void __init mem_total_pages(unsigned long physmem, unsigned long iomem,
 		     unsigned long highmem)
 {
-	struct page *p, *map;
-	unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
-	unsigned long iomem_len, iomem_pages, total_len, total_pages;
-	int i;
-
-	phys_pages = physmem >> PAGE_SHIFT;
-	phys_len = phys_pages * sizeof(struct page);
-
-	iomem_pages = iomem >> PAGE_SHIFT;
-	iomem_len = iomem_pages * sizeof(struct page);
+	unsigned long phys_pages, highmem_pages;
+	unsigned long iomem_pages, total_pages;
 
+	phys_pages    = physmem >> PAGE_SHIFT;
+	iomem_pages   = iomem   >> PAGE_SHIFT;
 	highmem_pages = highmem >> PAGE_SHIFT;
-	highmem_len = highmem_pages * sizeof(struct page);
-
-	total_pages = phys_pages + iomem_pages + highmem_pages;
-	total_len = phys_len + iomem_len + highmem_len;
 
-	map = alloc_bootmem_low_pages(total_len);
-	if (map == NULL)
-		return -ENOMEM;
-
-	for (i = 0; i < total_pages; i++) {
-		p = &map[i];
-		memset(p, 0, sizeof(struct page));
-		SetPageReserved(p);
-		INIT_LIST_HEAD(&p->lru);
-	}
+	total_pages   = phys_pages + iomem_pages + highmem_pages;
 
 	max_mapnr = total_pages;
-	return 0;
 }
 
 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 6043c76..dbd5bda 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -338,12 +338,7 @@ int __init linux_main(int argc, char **argv)
 	start_vm = VMALLOC_START;
 
 	setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
-	if (init_maps(physmem_size, iomem_size, highmem)) {
-		printf("Failed to allocate mem_map for %Lu bytes of physical "
-		       "memory and %Lu bytes of highmem\n", physmem_size,
-		       highmem);
-		exit(1);
-	}
+	mem_total_pages(physmem_size, iomem_size, highmem);
 
 	virtmem_size = physmem_size;
 	stack = (unsigned long) argv;
-- 
1.8.3.1

Re: [PATCH v2] delete unnecessary bootmem struct page array

[Real Name]

[-- Attachment #1: Type: text/plain, Size: 721 bytes --]

On Mon, Jun 16, 2014 at 11:15:23AM +0200, Geert Uytterhoeven wrote:
> On Mon, Jun 16, 2014 at 10:28 AM, Real Name <enjoymindful@gmail.com> wrote:
> >> > >> Can you please include in the changelog the commit sha1 which made the old init_maps() obsolete?

hi,

The commit sha1 had been included as required. Please review the attached patch. 
I only update the changlog of the patch.

thanks
> >
> > I think we need find out which commit deleted the line "mem_map = map;" in init_maps function.
> 
> 
> v2.6.12-rc1
> 
> commit 5678d7fc97ac75f7401ce77897773cc0bb3afee5

Geert, thank you.

> Author: Dave Hansen <haveblue@us.ibm.com>
> Date:   Sun Mar 13 00:22:56 2005 -0800
> 
>     [PATCH] no arch-specific mem_map init
> 

[-- Attachment #2: 0001-UML-delete-unnecessary-bootmem-struct-page-array.patch --]
[-- Type: text/x-diff, Size: 3816 bytes --]

From 29e5e83f8f3988ea1396d61b4d5764e7904f82c5 Mon Sep 17 00:00:00 2001
From: Honggang Li <enjoymindful@gmail.com>
Date: Mon, 16 Jun 2014 18:05:47 +0800
Subject: [PATCH] UML delete unnecessary bootmem struct page array

1) uml kernel bootmem managed through bootmem_data->node_bootmem_map,
not the struct page array, so the array is unnecessary.

2) the bootmem struct page array has been pointed by a *local* pointer,
struct page *map, in init_maps function. The array can be accessed only
in init_maps's scope. As a result, uml kernel wastes about 1% of total
memory.

3) commit 5678d7fc97ac75f7401ce77897773cc0bb3afee5 obsoleted
the init_maps function.

Signed-off-by: Honggang Li <enjoymindful@gmail.com>
---
 arch/um/include/shared/mem_user.h |  2 +-
 arch/um/kernel/physmem.c          | 32 ++++++--------------------------
 arch/um/kernel/um_arch.c          |  7 +------
 3 files changed, 8 insertions(+), 33 deletions(-)

diff --git a/arch/um/include/shared/mem_user.h b/arch/um/include/shared/mem_user.h
index 46384ac..cb84414 100644
--- a/arch/um/include/shared/mem_user.h
+++ b/arch/um/include/shared/mem_user.h
@@ -49,7 +49,7 @@ extern int iomem_size;
 extern int init_mem_user(void);
 extern void setup_memory(void *entry);
 extern unsigned long find_iomem(char *driver, unsigned long *len_out);
-extern int init_maps(unsigned long physmem, unsigned long iomem,
+extern void mem_total_pages(unsigned long physmem, unsigned long iomem,
 		     unsigned long highmem);
 extern unsigned long get_vm(unsigned long len);
 extern void setup_physmem(unsigned long start, unsigned long usable,
diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c
index 30fdd5d..549ecf3 100644
--- a/arch/um/kernel/physmem.c
+++ b/arch/um/kernel/physmem.c
@@ -22,39 +22,19 @@ EXPORT_SYMBOL(high_physmem);
 
 extern unsigned long long physmem_size;
 
-int __init init_maps(unsigned long physmem, unsigned long iomem,
+void __init mem_total_pages(unsigned long physmem, unsigned long iomem,
 		     unsigned long highmem)
 {
-	struct page *p, *map;
-	unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
-	unsigned long iomem_len, iomem_pages, total_len, total_pages;
-	int i;
-
-	phys_pages = physmem >> PAGE_SHIFT;
-	phys_len = phys_pages * sizeof(struct page);
-
-	iomem_pages = iomem >> PAGE_SHIFT;
-	iomem_len = iomem_pages * sizeof(struct page);
+	unsigned long phys_pages, highmem_pages;
+	unsigned long iomem_pages, total_pages;
 
+	phys_pages    = physmem >> PAGE_SHIFT;
+	iomem_pages   = iomem   >> PAGE_SHIFT;
 	highmem_pages = highmem >> PAGE_SHIFT;
-	highmem_len = highmem_pages * sizeof(struct page);
-
-	total_pages = phys_pages + iomem_pages + highmem_pages;
-	total_len = phys_len + iomem_len + highmem_len;
 
-	map = alloc_bootmem_low_pages(total_len);
-	if (map == NULL)
-		return -ENOMEM;
-
-	for (i = 0; i < total_pages; i++) {
-		p = &map[i];
-		memset(p, 0, sizeof(struct page));
-		SetPageReserved(p);
-		INIT_LIST_HEAD(&p->lru);
-	}
+	total_pages   = phys_pages + iomem_pages + highmem_pages;
 
 	max_mapnr = total_pages;
-	return 0;
 }
 
 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 6043c76..dbd5bda 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -338,12 +338,7 @@ int __init linux_main(int argc, char **argv)
 	start_vm = VMALLOC_START;
 
 	setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
-	if (init_maps(physmem_size, iomem_size, highmem)) {
-		printf("Failed to allocate mem_map for %Lu bytes of physical "
-		       "memory and %Lu bytes of highmem\n", physmem_size,
-		       highmem);
-		exit(1);
-	}
+	mem_total_pages(physmem_size, iomem_size, highmem);
 
 	virtmem_size = physmem_size;
 	stack = (unsigned long) argv;
-- 
1.8.3.1

Re: [PATCH v2] delete unnecessary bootmem struct page array

[Real Name]

On Mon, Jun 16, 2014 at 06:30:36PM +0800, Real Name wrote:
> On Mon, Jun 16, 2014 at 11:15:23AM +0200, Geert Uytterhoeven wrote:
> > On Mon, Jun 16, 2014 at 10:28 AM, Real Name <enjoymindful@gmail.com> wrote:
> > >> > >> Can you please include in the changelog the commit sha1 which made the old init_maps() obsolete?
> 
> hi,
> 
> The commit sha1 had been included as required. Please review the attached patch. 
> I only update the changlog of the patch.
>

hi, Rechard
ping?

> thanks
> > >
> > > I think we need find out which commit deleted the line "mem_map = map;" in init_maps function.
> > 
> > 
> > v2.6.12-rc1
> > 
> > commit 5678d7fc97ac75f7401ce77897773cc0bb3afee5
> 
> Geert, thank you.
> 
> > Author: Dave Hansen <haveblue@us.ibm.com>
> > Date:   Sun Mar 13 00:22:56 2005 -0800
> > 
> >     [PATCH] no arch-specific mem_map init
> > 

> From 29e5e83f8f3988ea1396d61b4d5764e7904f82c5 Mon Sep 17 00:00:00 2001
> From: Honggang Li <enjoymindful@gmail.com>
> Date: Mon, 16 Jun 2014 18:05:47 +0800
> Subject: [PATCH] UML delete unnecessary bootmem struct page array
> 
> 1) uml kernel bootmem managed through bootmem_data->node_bootmem_map,
> not the struct page array, so the array is unnecessary.
> 
> 2) the bootmem struct page array has been pointed by a *local* pointer,
> struct page *map, in init_maps function. The array can be accessed only
> in init_maps's scope. As a result, uml kernel wastes about 1% of total
> memory.
> 
> 3) commit 5678d7fc97ac75f7401ce77897773cc0bb3afee5 obsoleted
> the init_maps function.
> 
> Signed-off-by: Honggang Li <enjoymindful@gmail.com>
> ---
>  arch/um/include/shared/mem_user.h |  2 +-
>  arch/um/kernel/physmem.c          | 32 ++++++--------------------------
>  arch/um/kernel/um_arch.c          |  7 +------
>  3 files changed, 8 insertions(+), 33 deletions(-)
> 
> diff --git a/arch/um/include/shared/mem_user.h b/arch/um/include/shared/mem_user.h
> index 46384ac..cb84414 100644
> --- a/arch/um/include/shared/mem_user.h
> +++ b/arch/um/include/shared/mem_user.h
> @@ -49,7 +49,7 @@ extern int iomem_size;
>  extern int init_mem_user(void);
>  extern void setup_memory(void *entry);
>  extern unsigned long find_iomem(char *driver, unsigned long *len_out);
> -extern int init_maps(unsigned long physmem, unsigned long iomem,
> +extern void mem_total_pages(unsigned long physmem, unsigned long iomem,
>  		     unsigned long highmem);
>  extern unsigned long get_vm(unsigned long len);
>  extern void setup_physmem(unsigned long start, unsigned long usable,
> diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c
> index 30fdd5d..549ecf3 100644
> --- a/arch/um/kernel/physmem.c
> +++ b/arch/um/kernel/physmem.c
> @@ -22,39 +22,19 @@ EXPORT_SYMBOL(high_physmem);
>  
>  extern unsigned long long physmem_size;
>  
> -int __init init_maps(unsigned long physmem, unsigned long iomem,
> +void __init mem_total_pages(unsigned long physmem, unsigned long iomem,
>  		     unsigned long highmem)
>  {
> -	struct page *p, *map;
> -	unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
> -	unsigned long iomem_len, iomem_pages, total_len, total_pages;
> -	int i;
> -
> -	phys_pages = physmem >> PAGE_SHIFT;
> -	phys_len = phys_pages * sizeof(struct page);
> -
> -	iomem_pages = iomem >> PAGE_SHIFT;
> -	iomem_len = iomem_pages * sizeof(struct page);
> +	unsigned long phys_pages, highmem_pages;
> +	unsigned long iomem_pages, total_pages;
>  
> +	phys_pages    = physmem >> PAGE_SHIFT;
> +	iomem_pages   = iomem   >> PAGE_SHIFT;
>  	highmem_pages = highmem >> PAGE_SHIFT;
> -	highmem_len = highmem_pages * sizeof(struct page);
> -
> -	total_pages = phys_pages + iomem_pages + highmem_pages;
> -	total_len = phys_len + iomem_len + highmem_len;
>  
> -	map = alloc_bootmem_low_pages(total_len);
> -	if (map == NULL)
> -		return -ENOMEM;
> -
> -	for (i = 0; i < total_pages; i++) {
> -		p = &map[i];
> -		memset(p, 0, sizeof(struct page));
> -		SetPageReserved(p);
> -		INIT_LIST_HEAD(&p->lru);
> -	}
> +	total_pages   = phys_pages + iomem_pages + highmem_pages;
>  
>  	max_mapnr = total_pages;
> -	return 0;
>  }
>  
>  void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
> diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
> index 6043c76..dbd5bda 100644
> --- a/arch/um/kernel/um_arch.c
> +++ b/arch/um/kernel/um_arch.c
> @@ -338,12 +338,7 @@ int __init linux_main(int argc, char **argv)
>  	start_vm = VMALLOC_START;
>  
>  	setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
> -	if (init_maps(physmem_size, iomem_size, highmem)) {
> -		printf("Failed to allocate mem_map for %Lu bytes of physical "
> -		       "memory and %Lu bytes of highmem\n", physmem_size,
> -		       highmem);
> -		exit(1);
> -	}
> +	mem_total_pages(physmem_size, iomem_size, highmem);
>  
>  	virtmem_size = physmem_size;
>  	stack = (unsigned long) argv;
> -- 
> 1.8.3.1
> 

Re: [uml-devel] [PATCH v2] delete unnecessary bootmem struct page array

[Geert Uytterhoeven]

On Mon, Jun 16, 2014 at 5:28 AM, Real Name <enjoymindful@gmail.com> wrote:
> what is the pre-git linux tree? I searched it with google, but failed.

E.g. git.kernel.org/cgit/linux/kernel/git/tglx/history.git/


-- 
Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [uml-devel] [PATCH v2] delete unnecessary bootmem struct page array

[Paul Bolle]

On Mon, 2014-06-16 at 08:58 +0200, Geert Uytterhoeven wrote:
> On Mon, Jun 16, 2014 at 5:28 AM, Real Name <enjoymindful@gmail.com> wrote:
> > what is the pre-git linux tree? I searched it with google, but failed.
> 
> E.g. git.kernel.org/cgit/linux/kernel/git/tglx/history.git/

The archive at https://archive.org/details/git-history-of-linux seems to
be the most comprehensive. I use it regularly. It can even be made to
track the current tree. The tags for pre-v2.6.12-rc2 releases need to be
added manually, which is quite a bit of work.

Is there something better out there?


Paul Bolle