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xen/balloon: find non-conflicting regions to place hotplugged memory

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Instead of placing hotplugged memory at the end of RAM (which may
conflict with PCI devices or reserved regions) use allocate_resource()
to get a new, suitably aligned resource that does not conflict.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
v3:
- Remove stale comment.
This commit is contained in:
David Vrabel 2015-06-24 15:58:42 +01:00
parent f5775e0b61
commit 55b3da98a4
1 changed files with 53 additions and 20 deletions
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73
drivers/xen/balloon.c
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@ -54,6 +54,7 @@
#include <linux/memory.h>
#include <linux/memory_hotplug.h>
#include <linux/percpu-defs.h>
#include <linux/slab.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
@ -208,26 +209,56 @@ static bool balloon_is_inflated(void)
return false;
}
/*
* reserve_additional_memory() adds memory region of size >= credit above
* max_pfn. New region is section aligned and size is modified to be multiple
* of section size. Those features allow optimal use of address space and
* establish proper alignment when this function is called first time after
* boot (last section not fully populated at boot time contains unused memory
* pages with PG_reserved bit not set; online_pages_range() does not allow page
* onlining in whole range if first onlined page does not have PG_reserved
* bit set). Real size of added memory is established at page onlining stage.
*/
static struct resource *additional_memory_resource(phys_addr_t size)
{
struct resource *res;
int ret;
res = kzalloc(sizeof(*res), GFP_KERNEL);
if (!res)
return NULL;
res->name = "System RAM";
res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
ret = allocate_resource(&iomem_resource, res,
size, 0, -1,
PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL);
if (ret < 0) {
pr_err("Cannot allocate new System RAM resource\n");
kfree(res);
return NULL;
}
return res;
}
static void release_memory_resource(struct resource *resource)
{
if (!resource)
return;
/*
* No need to reset region to identity mapped since we now
* know that no I/O can be in this region
*/
release_resource(resource);
kfree(resource);
}
static enum bp_state reserve_additional_memory(long credit)
{
struct resource *resource;
int nid, rc;
u64 hotplug_start_paddr;
unsigned long balloon_hotplug = credit;
unsigned long balloon_hotplug;
hotplug_start_paddr = PFN_PHYS(SECTION_ALIGN_UP(max_pfn));
balloon_hotplug = round_up(balloon_hotplug, PAGES_PER_SECTION);
nid = memory_add_physaddr_to_nid(hotplug_start_paddr);
balloon_hotplug = round_up(credit, PAGES_PER_SECTION);
resource = additional_memory_resource(balloon_hotplug * PAGE_SIZE);
if (!resource)
goto err;
nid = memory_add_physaddr_to_nid(resource->start);
#ifdef CONFIG_XEN_HAVE_PVMMU
/*
@ -242,21 +273,20 @@ static enum bp_state reserve_additional_memory(long credit)
if (!xen_feature(XENFEAT_auto_translated_physmap)) {
unsigned long pfn, i;
pfn = PFN_DOWN(hotplug_start_paddr);
pfn = PFN_DOWN(resource->start);
for (i = 0; i < balloon_hotplug; i++) {
if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) {
pr_warn("set_phys_to_machine() failed, no memory added\n");
return BP_ECANCELED;
goto err;
}
}
}
#endif
rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << PAGE_SHIFT);
rc = add_memory_resource(nid, resource);
if (rc) {
pr_warn("Cannot add additional memory (%i)\n", rc);
return BP_ECANCELED;
goto err;
}
balloon_hotplug -= credit;
@ -265,6 +295,9 @@ static enum bp_state reserve_additional_memory(long credit)
balloon_stats.balloon_hotplug = balloon_hotplug;
return BP_DONE;
err:
release_memory_resource(resource);
return BP_ECANCELED;
}
static void xen_online_page(struct page *page)