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Re: Patch for sparsemem support

To: Ralf Baechle <ralf@linux-mips.org>
Subject: Re: Patch for sparsemem support
From: Chad Reese <creese@caviumnetworks.com>
Date: Wed, 24 May 2006 09:09:11 -0700
Cc: linux-mips@linux-mips.org
In-reply-to: <20060524014131.GB3205@linux-mips.org>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <4470CAFE.5000404@caviumnetworks.com> <20060524014131.GB3205@linux-mips.org>
Sender: linux-mips-bounce@linux-mips.org
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.7.8) Gecko/20060504 Debian/1.7.8-1sarge6
Resend of previous patch

I've attached the patch compressed with gzip and as clear text. Hopefully one of them will survive whatever corruption occurred last time.

Chad

---

The patch below allows sparsemem to work for Mips64. This is my first foray into the boot memory handling code, so hopefully I haven't made any serious blunders. Unfortunately the Octeon processor I made the changes for isn't currently in the linux-mips.org tree. This means there isn't an example of sparsemem usage yet. I plan to work at fixing this soon.

Other than various ifdef changes, the most important change was moving memory_present() in arch/mips/kernel/setup.c. When you're using sparsemem extreme, this function does an allocate for bootmem. This would always fail since init_bootmem hasn't been called yet. I moved memory_present after free_bootmem. This only marks actual memory ranges as present instead of the entire address space.

This patch was made against 2.6.16.16

Signed-off-by: Chad Reese  <creese@caviumnetworks.com>

 arch/mips/kernel/setup.c     |    3 +--
 arch/mips/mm/init.c          |    2 +-
 include/asm-mips/page.h      |    2 ++
 include/asm-mips/sparsemem.h |   14 ++++++++++++++
 include/linux/mm.h           |    2 +-
 include/linux/mmzone.h       |    1 +
 6 files changed, 20 insertions(+), 4 deletions(-)

Ralf Baechle wrote:
On Sun, May 21, 2006 at 01:18:06PM -0700, Chad Reese wrote:

Looks ok - but the patch is corrupt, can you resend?

  Ralf

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index d9293c5..406afce 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -358,8 +358,6 @@ static inline void bootmem_init(void)
        }
 #endif

-       memory_present(0, first_usable_pfn, max_low_pfn);
-
        /* Initialize the boot-time allocator with low memory only.  */
        bootmap_size = init_bootmem(first_usable_pfn, max_low_pfn);

@@ -413,6 +411,7 @@ static inline void bootmem_init(void)

                /* Register lowmem ranges */
                free_bootmem(PFN_PHYS(curr_pfn), PFN_PHYS(size));
+               memory_present(0, curr_pfn, curr_pfn + size - 1);
        }

        /* Reserve the bootmap memory.  */
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 0ff9a34..f151373 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -228,7 +228,7 @@ void __init mem_init(void)
        for (tmp = 0; tmp < max_low_pfn; tmp++)
                if (page_is_ram(tmp)) {
                        ram++;
-                       if (PageReserved(mem_map+tmp))
+                       if (PageReserved(pfn_to_page(tmp)))
                                reservedpages++;
                }

diff --git a/include/asm-mips/page.h b/include/asm-mips/page.h
index 399d731..103290a 100644
--- a/include/asm-mips/page.h
+++ b/include/asm-mips/page.h
@@ -145,11 +145,13 @@ typedef struct { unsigned long pgprot; }

 #define pfn_to_kaddr(pfn)      __va((pfn) << PAGE_SHIFT)

+#ifndef CONFIG_SPARSEMEM
 #ifndef CONFIG_NEED_MULTIPLE_NODES
 #define pfn_to_page(pfn)       (mem_map + (pfn))
 #define page_to_pfn(page)      ((unsigned long)((page) - mem_map))
 #define pfn_valid(pfn)         ((pfn) < max_mapnr)
 #endif
+#endif

 #define virt_to_page(kaddr)    pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
 #define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
diff --git a/include/asm-mips/sparsemem.h b/include/asm-mips/sparsemem.h
new file mode 100644
index 0000000..795ac6c
--- /dev/null
+++ b/include/asm-mips/sparsemem.h
@@ -0,0 +1,14 @@
+#ifndef _MIPS_SPARSEMEM_H
+#define _MIPS_SPARSEMEM_H
+#ifdef CONFIG_SPARSEMEM
+
+/*
+ * SECTION_SIZE_BITS           2^N: how big each section will be
+ * MAX_PHYSMEM_BITS            2^N: how much memory we can have in that space
+ */
+#define SECTION_SIZE_BITS       28
+#define MAX_PHYSMEM_BITS        35
+
+#endif /* CONFIG_SPARSEMEM */
+#endif /* _MIPS_SPARSEMEM_H */
+
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 279446e..a1c4788 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -506,7 +506,7 @@ static inline void set_page_links(struct
        set_page_section(page, pfn_to_section_nr(pfn));
 }

-#ifndef CONFIG_DISCONTIGMEM
+#if !defined(CONFIG_DISCONTIGMEM) && !defined(CONFIG_SPARSEMEM)
 /* The array of struct pages - for discontigmem use pgdat->lmem_map */
 extern struct page *mem_map;
 #endif
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index ebfc238..807616f 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -14,6 +14,7 @@
 #include <linux/init.h>
 #include <linux/seqlock.h>
 #include <asm/atomic.h>
+#include <asm/page.h>

 /* Free memory management - zoned buddy allocator.  */
 #ifndef CONFIG_FORCE_MAX_ZONEORDER

Attachment: sparsemem_support_mips_fixed.patch.gz
Description: Unix tar archive

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