On 08/04/2016 07:12 PM, Srikar Dronamraju wrote:
Expand the scope of the existing dma_reserve to accommodate other memory
reserves too. Accordingly rename variable dma_reserve to
nr_memory_reserve.
set_memory_reserve also takes a new parameter that helps to identify if
the current value needs to be incremented.
Suggested-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/e820.c | 2 +-
include/linux/mm.h | 2 +-
mm/page_alloc.c | 20 ++++++++++++--------
3 files changed, 14 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 621b501..d935983 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1188,6 +1188,6 @@ void __init memblock_find_dma_reserve(void)
nr_free_pages += end_pfn - start_pfn;
}
- set_dma_reserve(nr_pages - nr_free_pages);
+ set_memory_reserve(nr_pages - nr_free_pages, false);
#endif
}
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8f468e0..c884ffb 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1886,7 +1886,7 @@ extern int __meminit __early_pfn_to_nid(unsigned long pfn,
struct mminit_pfnnid_cache *state);
#endif
-extern void set_dma_reserve(unsigned long new_dma_reserve);
+extern void set_memory_reserve(unsigned long nr_reserve, bool inc);
extern void memmap_init_zone(unsigned long, int, unsigned long,
unsigned long, enum memmap_context);
extern void setup_per_zone_wmarks(void);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c1069ef..a154c2f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -253,7 +253,7 @@ int watermark_scale_factor = 10;
static unsigned long __meminitdata nr_kernel_pages;
static unsigned long __meminitdata nr_all_pages;
-static unsigned long __meminitdata dma_reserve;
+static unsigned long __meminitdata nr_memory_reserve;
#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
@@ -5493,10 +5493,10 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
}
/* Account for reserved pages */
- if (j == 0 && freesize > dma_reserve) {
- freesize -= dma_reserve;
+ if (j == 0 && freesize > nr_memory_reserve) {
Will this really work (together with patch 2) as intended?
This j == 0 means that we are doing this only for the first zone, which
is ZONE_DMA (or ZONE_DMA32) on node 0 on many systems. I.e. I don't
think it's really true that "dma_reserve has nothing to do with DMA or
ZONE_DMA".
This zone will have limited amount of memory, so the "freesize >
nr_memory_reserve" will easily be false once you set this to many
gigabytes, so in fact nothing will get subtracted.
On the other hand if the kernel has both CONFIG_ZONE_DMA and
CONFIG_ZONE_DMA32 disabled, then j == 0 will be true for ZONE_NORMAL.
This zone might be present on multiple nodes (unless they are configured
as movable) and then the value intended to be global will be subtracted
from several nodes.
I don't know what's the exact ppc64 situation here, perhaps there are
indeed no DMA/DMA32 zones, and the fadump kernel only uses one node, so
it works in the end, but it doesn't seem much robust to me?
+ freesize -= nr_memory_reserve;
printk(KERN_DEBUG " %s zone: %lu pages reserved\n",
- zone_names[0], dma_reserve);
+ zone_names[0], nr_memory_reserve);
}
if (!is_highmem_idx(j))
@@ -6186,8 +6186,9 @@ void __init mem_init_print_info(const char *str)
}
/**
- * set_dma_reserve - set the specified number of pages reserved in the first zone
- * @new_dma_reserve: The number of pages to mark reserved
+ * set_memory_reserve - set number of pages reserved in the first zone
+ * @nr_reserve: The number of pages to mark reserved
+ * @inc: true increment to existing value; false set new value.
*
* The per-cpu batchsize and zone watermarks are determined by managed_pages.
* In the DMA zone, a significant percentage may be consumed by kernel image
@@ -6196,9 +6197,12 @@ void __init mem_init_print_info(const char *str)
* first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
* smaller per-cpu batchsize.
*/
-void __init set_dma_reserve(unsigned long new_dma_reserve)
+void __init set_memory_reserve(unsigned long nr_reserve, bool inc)
{
- dma_reserve = new_dma_reserve;
+ if (inc)
+ nr_memory_reserve += nr_reserve;
+ else
+ nr_memory_reserve = nr_reserve;
}
void __init free_area_init(unsigned long *zones_size)
--
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