lkml.org 
[lkml]   [2012]   [Jul]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[RFC PATCH 7/8] x86: make __split_large_page() generally avialable
We need to clear page table after calling __remove_pages(). We may
need to clear part of pmd or pud's entry when clearing the page table.
So we need to split it to small page. Make __split_large_page()
generally avialable, and we call call this function to split large page.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Christoph Lameter <cl@linux.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
arch/x86/include/asm/pgtable_types.h | 1 +
arch/x86/mm/pageattr.c | 47 ++++++++++++++++++----------------
2 files changed, 26 insertions(+), 22 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 013286a..b725af2 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -334,6 +334,7 @@ static inline void update_page_count(int level, unsigned long pages) { }
* as a pte too.
*/
extern pte_t *lookup_address(unsigned long address, unsigned int *level);
+extern int __split_large_page(pte_t *kpte, unsigned long address, pte_t *pbase);

#endif /* !__ASSEMBLY__ */

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index a718e0d..7dcb6f9 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -501,21 +501,13 @@ out_unlock:
return do_split;
}

-static int split_large_page(pte_t *kpte, unsigned long address)
+int __split_large_page(pte_t *kpte, unsigned long address, pte_t *pbase)
{
unsigned long pfn, pfninc = 1;
unsigned int i, level;
- pte_t *pbase, *tmp;
+ pte_t *tmp;
pgprot_t ref_prot;
- struct page *base;
-
- if (!debug_pagealloc)
- spin_unlock(&cpa_lock);
- base = alloc_pages(GFP_KERNEL | __GFP_NOTRACK, 0);
- if (!debug_pagealloc)
- spin_lock(&cpa_lock);
- if (!base)
- return -ENOMEM;
+ struct page *base = virt_to_page(pbase);

spin_lock(&pgd_lock);
/*
@@ -523,10 +515,11 @@ static int split_large_page(pte_t *kpte, unsigned long address)
* up for us already:
*/
tmp = lookup_address(address, &level);
- if (tmp != kpte)
- goto out_unlock;
+ if (tmp != kpte) {
+ spin_unlock(&pgd_lock);
+ return 1;
+ }

- pbase = (pte_t *)page_address(base);
paravirt_alloc_pte(&init_mm, page_to_pfn(base));
ref_prot = pte_pgprot(pte_clrhuge(*kpte));
/*
@@ -579,17 +572,27 @@ static int split_large_page(pte_t *kpte, unsigned long address)
* going on.
*/
__flush_tlb_all();
+ spin_unlock(&pgd_lock);

- base = NULL;
+ return 0;
+}

-out_unlock:
- /*
- * If we dropped out via the lookup_address check under
- * pgd_lock then stick the page back into the pool:
- */
- if (base)
+static int split_large_page(pte_t *kpte, unsigned long address)
+{
+ pte_t *pbase;
+ struct page *base;
+
+ if (!debug_pagealloc)
+ spin_unlock(&cpa_lock);
+ base = alloc_pages(GFP_KERNEL | __GFP_NOTRACK, 0);
+ if (!debug_pagealloc)
+ spin_lock(&cpa_lock);
+ if (!base)
+ return -ENOMEM;
+
+ pbase = (pte_t *)page_address(base);
+ if (__split_large_page(kpte, address, pbase))
__free_page(base);
- spin_unlock(&pgd_lock);

return 0;
}
--
1.7.1


\
 
 \ /
  Last update: 2012-07-20 10:02    [W:0.101 / U:2.696 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site