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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v3 16/19] mini-os: map page allocator's bitmap to virtual kernel area for ballooning
In case of CONFIG_BALLOON the page allocator's bitmap needs some space
to be able to grow. Remap it to kernel virtual area if the preallocated
area isn't large enough.
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
V3: - add assertion as requested by Samuel Thibault
- rename functions to have mm_ prefix as requested by Samuel Thibault
---
balloon.c | 18 ++++++++++++++++++
include/balloon.h | 2 ++
include/mm.h | 6 ++++++
mm.c | 43 ++++++++++++++++++++++---------------------
4 files changed, 48 insertions(+), 21 deletions(-)
diff --git a/balloon.c b/balloon.c
index 1ec113d..78b30af 100644
--- a/balloon.c
+++ b/balloon.c
@@ -44,3 +44,21 @@ void get_max_pages(void)
nr_max_pages = ret;
printk("Maximum memory size: %ld pages\n", nr_max_pages);
}
+
+void mm_alloc_bitmap_remap(void)
+{
+ unsigned long i;
+
+ if ( mm_bitmap_size >= ((nr_max_pages + 1) >> (PAGE_SHIFT + 3)) )
+ return;
+
+ for ( i = 0; i < mm_bitmap_size; i += PAGE_SIZE )
+ {
+ map_frame_rw(virt_kernel_area_end + i,
+ virt_to_mfn((unsigned long)(mm_bitmap) + i));
+ }
+
+ mm_bitmap = (unsigned long *)virt_kernel_area_end;
+ virt_kernel_area_end += round_pgup((nr_max_pages + 1) >> (PAGE_SHIFT + 3));
+ ASSERT(virt_kernel_area_end <= VIRT_DEMAND_AREA);
+}
diff --git a/include/balloon.h b/include/balloon.h
index b0d0ebf..9154f44 100644
--- a/include/balloon.h
+++ b/include/balloon.h
@@ -31,11 +31,13 @@ extern unsigned long virt_kernel_area_end;
void get_max_pages(void);
void arch_remap_p2m(unsigned long max_pfn);
+void mm_alloc_bitmap_remap(void);
#else /* CONFIG_BALLOON */
static inline void get_max_pages(void) { }
static inline void arch_remap_p2m(unsigned long max_pfn) { }
+static inline void mm_alloc_bitmap_remap(void) { }
#endif /* CONFIG_BALLOON */
#endif /* _BALLOON_H_ */
diff --git a/include/mm.h b/include/mm.h
index 6add683..ab56445 100644
--- a/include/mm.h
+++ b/include/mm.h
@@ -42,8 +42,14 @@
#define STACK_SIZE_PAGE_ORDER __STACK_SIZE_PAGE_ORDER
#define STACK_SIZE __STACK_SIZE
+#define round_pgdown(_p) ((_p) & PAGE_MASK)
+#define round_pgup(_p) (((_p) + (PAGE_SIZE - 1)) & PAGE_MASK)
+
extern unsigned long nr_free_pages;
+extern unsigned long *mm_bitmap;
+extern unsigned long mm_bitmap_size;
+
void init_mm(void);
unsigned long alloc_pages(int order);
#define alloc_page() alloc_pages(0)
diff --git a/mm.c b/mm.c
index 707a3e0..e2f55af 100644
--- a/mm.c
+++ b/mm.c
@@ -48,11 +48,13 @@
* One bit per page of memory. Bit set => page is allocated.
*/
-static unsigned long *alloc_bitmap;
+unsigned long *mm_bitmap;
+unsigned long mm_bitmap_size;
+
#define PAGES_PER_MAPWORD (sizeof(unsigned long) * 8)
#define allocated_in_map(_pn) \
-(alloc_bitmap[(_pn)/PAGES_PER_MAPWORD] & (1UL<<((_pn)&(PAGES_PER_MAPWORD-1))))
+(mm_bitmap[(_pn)/PAGES_PER_MAPWORD] & (1UL<<((_pn)&(PAGES_PER_MAPWORD-1))))
unsigned long nr_free_pages;
@@ -61,8 +63,8 @@ unsigned long nr_free_pages;
* -(1<<n) sets all bits >= n.
* (1<<n)-1 sets all bits < n.
* Variable names in map_{alloc,free}:
- * *_idx == Index into `alloc_bitmap' array.
- * *_off == Bit offset within an element of the `alloc_bitmap' array.
+ * *_idx == Index into `mm_bitmap' array.
+ * *_off == Bit offset within an element of the `mm_bitmap' array.
*/
static void map_alloc(unsigned long first_page, unsigned long nr_pages)
@@ -76,13 +78,13 @@ static void map_alloc(unsigned long first_page, unsigned
long nr_pages)
if ( curr_idx == end_idx )
{
- alloc_bitmap[curr_idx] |= ((1UL<<end_off)-1) & -(1UL<<start_off);
+ mm_bitmap[curr_idx] |= ((1UL<<end_off)-1) & -(1UL<<start_off);
}
else
{
- alloc_bitmap[curr_idx] |= -(1UL<<start_off);
- while ( ++curr_idx < end_idx ) alloc_bitmap[curr_idx] = ~0UL;
- alloc_bitmap[curr_idx] |= (1UL<<end_off)-1;
+ mm_bitmap[curr_idx] |= -(1UL<<start_off);
+ while ( ++curr_idx < end_idx ) mm_bitmap[curr_idx] = ~0UL;
+ mm_bitmap[curr_idx] |= (1UL<<end_off)-1;
}
nr_free_pages -= nr_pages;
@@ -102,13 +104,13 @@ static void map_free(unsigned long first_page, unsigned
long nr_pages)
if ( curr_idx == end_idx )
{
- alloc_bitmap[curr_idx] &= -(1UL<<end_off) | ((1UL<<start_off)-1);
+ mm_bitmap[curr_idx] &= -(1UL<<end_off) | ((1UL<<start_off)-1);
}
else
{
- alloc_bitmap[curr_idx] &= (1UL<<start_off)-1;
- while ( ++curr_idx != end_idx ) alloc_bitmap[curr_idx] = 0;
- alloc_bitmap[curr_idx] &= -(1UL<<end_off);
+ mm_bitmap[curr_idx] &= (1UL<<start_off)-1;
+ while ( ++curr_idx != end_idx ) mm_bitmap[curr_idx] = 0;
+ mm_bitmap[curr_idx] &= -(1UL<<end_off);
}
}
@@ -137,9 +139,6 @@ static chunk_head_t *free_head[FREELIST_SIZE];
static chunk_head_t free_tail[FREELIST_SIZE];
#define FREELIST_EMPTY(_l) ((_l)->next == NULL)
-#define round_pgdown(_p) ((_p)&PAGE_MASK)
-#define round_pgup(_p) (((_p)+(PAGE_SIZE-1))&PAGE_MASK)
-
/*
* Initialise allocator, placing addresses [@min,@max] in free pool.
* @min and @max are PHYSICAL addresses.
@@ -147,7 +146,7 @@ static chunk_head_t free_tail[FREELIST_SIZE];
static void init_page_allocator(unsigned long min, unsigned long max)
{
int i;
- unsigned long range, bitmap_size;
+ unsigned long range;
chunk_head_t *ch;
chunk_tail_t *ct;
for ( i = 0; i < FREELIST_SIZE; i++ )
@@ -161,14 +160,14 @@ static void init_page_allocator(unsigned long min,
unsigned long max)
max = round_pgdown(max);
/* Allocate space for the allocation bitmap. */
- bitmap_size = (max+1) >> (PAGE_SHIFT+3);
- bitmap_size = round_pgup(bitmap_size);
- alloc_bitmap = (unsigned long *)to_virt(min);
- min += bitmap_size;
+ mm_bitmap_size = (max + 1) >> (PAGE_SHIFT + 3);
+ mm_bitmap_size = round_pgup(mm_bitmap_size);
+ mm_bitmap = (unsigned long *)to_virt(min);
+ min += mm_bitmap_size;
range = max - min;
/* All allocated by default. */
- memset(alloc_bitmap, ~0, bitmap_size);
+ memset(mm_bitmap, ~0, mm_bitmap_size);
/* Free up the memory we've been given to play with. */
map_free(PHYS_PFN(min), range>>PAGE_SHIFT);
@@ -198,6 +197,8 @@ static void init_page_allocator(unsigned long min, unsigned
long max)
free_head[i] = ch;
ct->level = i;
}
+
+ mm_alloc_bitmap_remap();
}
--
2.6.6
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