From aa24411b6717fd1e6ecef281bec497f6f30bbd66 Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Wed, 28 Sep 2011 17:46:32 +0100 Subject: xen/balloon: account for pages released during memory setup In xen_memory_setup() pages that occur in gaps in the memory map are released back to Xen. This reduces the domain's current page count in the hypervisor. The Xen balloon driver does not correctly decrease its initial current_pages count to reflect this. If 'delta' pages are released and the target is adjusted the resulting reservation is always 'delta' less than the requested target. This affects dom0 if the initial allocation of pages overlaps the PCI memory region but won't affect most domU guests that have been setup with pseudo-physical memory maps that don't have gaps. Fix this by accouting for the released pages when starting the balloon driver. If the domain's targets are managed by xapi, the domain may eventually run out of memory and die because xapi currently gets its target calculations wrong and whenever it is restarted it always reduces the target by 'delta'. Signed-off-by: David Vrabel Signed-off-by: Konrad Rzeszutek Wilk --- include/xen/page.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/xen/page.h b/include/xen/page.h index 0be36b976f4b..92b61f8c772c 100644 --- a/include/xen/page.h +++ b/include/xen/page.h @@ -5,4 +5,6 @@ extern phys_addr_t xen_extra_mem_start, xen_extra_mem_size; +extern unsigned long xen_released_pages; + #endif /* _XEN_PAGE_H */ -- cgit v1.2.3 From 8b5d44a5ac93cd7a1b044db3ff0ba4955b4ba5ec Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Wed, 28 Sep 2011 17:46:34 +0100 Subject: xen: allow balloon driver to use more than one memory region Allow the xen balloon driver to populate its list of extra pages from more than one region of memory. This will allow platforms to provide (for example) a region of low memory and a region of high memory. The maximum possible number of extra regions is 128 (== E820MAX) which is quite large so xen_extra_mem is placed in __initdata. This is safe as both xen_memory_setup() and balloon_init() are in __init. The balloon regions themselves are not altered (i.e., there is still only the one region). Signed-off-by: David Vrabel Signed-off-by: Konrad Rzeszutek Wilk --- arch/x86/xen/setup.c | 20 ++++++++++---------- drivers/xen/balloon.c | 44 +++++++++++++++++++++++++++----------------- include/xen/page.h | 10 +++++++++- 3 files changed, 46 insertions(+), 28 deletions(-) (limited to 'include') diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index c983717c018c..0c8e974c738a 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -37,7 +37,7 @@ extern void xen_syscall_target(void); extern void xen_syscall32_target(void); /* Amount of extra memory space we add to the e820 ranges */ -phys_addr_t xen_extra_mem_start, xen_extra_mem_size; +struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata; /* Number of pages released from the initial allocation. */ unsigned long xen_released_pages; @@ -59,7 +59,7 @@ static void __init xen_add_extra_mem(unsigned long pages) unsigned long pfn; u64 size = (u64)pages * PAGE_SIZE; - u64 extra_start = xen_extra_mem_start + xen_extra_mem_size; + u64 extra_start = xen_extra_mem[0].start + xen_extra_mem[0].size; if (!pages) return; @@ -69,7 +69,7 @@ static void __init xen_add_extra_mem(unsigned long pages) memblock_x86_reserve_range(extra_start, extra_start + size, "XEN EXTRA"); - xen_extra_mem_size += size; + xen_extra_mem[0].size += size; xen_max_p2m_pfn = PFN_DOWN(extra_start + size); @@ -242,7 +242,7 @@ char * __init xen_memory_setup(void) memcpy(map_raw, map, sizeof(map)); e820.nr_map = 0; - xen_extra_mem_start = mem_end; + xen_extra_mem[0].start = mem_end; for (i = 0; i < memmap.nr_entries; i++) { unsigned long long end; @@ -270,8 +270,8 @@ char * __init xen_memory_setup(void) e820_add_region(end, delta, E820_UNUSABLE); } - if (map[i].size > 0 && end > xen_extra_mem_start) - xen_extra_mem_start = end; + if (map[i].size > 0 && end > xen_extra_mem[0].start) + xen_extra_mem[0].start = end; /* Add region if any remains */ if (map[i].size > 0) @@ -279,10 +279,10 @@ char * __init xen_memory_setup(void) } /* Align the balloon area so that max_low_pfn does not get set * to be at the _end_ of the PCI gap at the far end (fee01000). - * Note that xen_extra_mem_start gets set in the loop above to be - * past the last E820 region. */ - if (xen_initial_domain() && (xen_extra_mem_start < (1ULL<<32))) - xen_extra_mem_start = (1ULL<<32); + * Note that the start of balloon area gets set in the loop above + * to be past the last E820 region. */ + if (xen_initial_domain() && (xen_extra_mem[0].start < (1ULL<<32))) + xen_extra_mem[0].start = (1ULL<<32); /* * In domU, the ISA region is normal, usable memory, but we diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index 9efb993090aa..fc43b53651d7 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -555,11 +555,32 @@ void free_xenballooned_pages(int nr_pages, struct page** pages) } EXPORT_SYMBOL(free_xenballooned_pages); -static int __init balloon_init(void) +static void __init balloon_add_region(unsigned long start_pfn, + unsigned long pages) { unsigned long pfn, extra_pfn_end; struct page *page; + /* + * If the amount of usable memory has been limited (e.g., with + * the 'mem' command line parameter), don't add pages beyond + * this limit. + */ + extra_pfn_end = min(max_pfn, start_pfn + pages); + + for (pfn = start_pfn; pfn < extra_pfn_end; pfn++) { + page = pfn_to_page(pfn); + /* totalram_pages and totalhigh_pages do not + include the boot-time balloon extension, so + don't subtract from it. */ + __balloon_append(page); + } +} + +static int __init balloon_init(void) +{ + int i; + if (!xen_domain()) return -ENODEV; @@ -587,23 +608,12 @@ static int __init balloon_init(void) /* * Initialize the balloon with pages from the extra memory - * region (see arch/x86/xen/setup.c). - * - * If the amount of usable memory has been limited (e.g., with - * the 'mem' command line parameter), don't add pages beyond - * this limit. + * regions (see arch/x86/xen/setup.c). */ - extra_pfn_end = min(max_pfn, - (unsigned long)PFN_DOWN(xen_extra_mem_start - + xen_extra_mem_size)); - for (pfn = PFN_UP(xen_extra_mem_start); - pfn < extra_pfn_end; - pfn++) { - page = pfn_to_page(pfn); - /* totalram_pages and totalhigh_pages do not include the boot-time - balloon extension, so don't subtract from it. */ - __balloon_append(page); - } + for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) + if (xen_extra_mem[i].size) + balloon_add_region(PFN_UP(xen_extra_mem[i].start), + PFN_DOWN(xen_extra_mem[i].size)); return 0; } diff --git a/include/xen/page.h b/include/xen/page.h index 92b61f8c772c..12765b6f9517 100644 --- a/include/xen/page.h +++ b/include/xen/page.h @@ -3,7 +3,15 @@ #include -extern phys_addr_t xen_extra_mem_start, xen_extra_mem_size; +struct xen_memory_region { + phys_addr_t start; + phys_addr_t size; +}; + +#define XEN_EXTRA_MEM_MAX_REGIONS 128 /* == E820MAX */ + +extern __initdata +struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS]; extern unsigned long xen_released_pages; -- cgit v1.2.3