[PATCH] x86_64: Account mem_map in VM holes accounting
The VM needs to know about lost memory in zones to accurately
balance dirty pages. This patch accounts mem_map in there too,
which fixes a constant errror of a few percent. Also some
other misc mappings and the kernel text itself are accounted
too.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index a1ad4cc..2b1d6c3 100644
--- a/arch/x86_64/mm/init.c
+++ b/arch/x86_64/mm/init.c
@@ -47,6 +47,8 @@
extern char _stext[];
+static unsigned long dma_reserve __initdata;
+
DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
/*
@@ -354,6 +356,21 @@
w += z[i];
h[i] = e820_hole_size(s, w);
}
+
+ /* Add the space pace needed for mem_map to the holes too. */
+ for (i = 0; i < MAX_NR_ZONES; i++)
+ h[i] += (z[i] * sizeof(struct page)) / PAGE_SIZE;
+
+ /* The 16MB DMA zone has the kernel and other misc mappings.
+ Account them too */
+ if (h[ZONE_DMA]) {
+ h[ZONE_DMA] += dma_reserve;
+ if (h[ZONE_DMA] >= z[ZONE_DMA]) {
+ printk(KERN_WARNING
+ "Kernel too large and filling up ZONE_DMA?\n");
+ h[ZONE_DMA] = z[ZONE_DMA];
+ }
+ }
}
#ifndef CONFIG_NUMA
@@ -510,6 +527,8 @@
#else
reserve_bootmem(phys, len);
#endif
+ if (phys+len <= MAX_DMA_PFN*PAGE_SIZE)
+ dma_reserve += len / PAGE_SIZE;
}
int kern_addr_valid(unsigned long addr)
