[people/pmueller/ipfire-2.x.git] / src / patches / suse-2.6.27.39 / patches.xen / xen-x86-dcr-fallback

Subject: Add fallback when XENMEM_exchange fails to replace contiguous region
From: jbeulich@novell.com
Patch-mainline: obsolete
References: 181869

This avoids losing precious special memory in places where any memory can be
used.

--- sle11-2009-08-26.orig/arch/x86/mm/hypervisor.c	2009-08-31 11:47:04.000000000 +0200
+++ sle11-2009-08-26/arch/x86/mm/hypervisor.c	2009-03-30 12:18:24.000000000 +0200
@@ -42,6 +42,7 @@
 #include <xen/interface/memory.h>
 #include <linux/module.h>
 #include <linux/percpu.h>
+#include <linux/highmem.h>
 #include <asm/tlbflush.h>
 #include <linux/highmem.h>
 
@@ -712,6 +713,83 @@ void xen_destroy_contiguous_region(unsig
 		BUG();
 
 	balloon_unlock(flags);
+
+	if (unlikely(!success)) {
+		/* Try hard to get the special memory back to Xen. */
+		exchange.in.extent_order = 0;
+		set_xen_guest_handle(exchange.in.extent_start, &in_frame);
+
+		for (i = 0; i < (1U<<order); i++) {
+			struct page *page = alloc_page(__GFP_HIGHMEM|__GFP_COLD);
+			unsigned long pfn;
+			mmu_update_t mmu;
+			unsigned int j = 0;
+
+			if (!page) {
+				printk(KERN_WARNING "Xen and kernel out of memory "
+				       "while trying to release an order %u "
+				       "contiguous region\n", order);
+				break;
+			}
+			pfn = page_to_pfn(page);
+
+			balloon_lock(flags);
+
+			if (!PageHighMem(page)) {
+				void *v = __va(pfn << PAGE_SHIFT);
+
+				scrub_pages(v, 1);
+				MULTI_update_va_mapping(cr_mcl + j, (unsigned long)v,
+							__pte_ma(0), UVMF_INVLPG|UVMF_ALL);
+				++j;
+			}
+#ifdef CONFIG_XEN_SCRUB_PAGES
+			else {
+				scrub_pages(kmap(page), 1);
+				kunmap(page);
+				kmap_flush_unused();
+			}
+#endif
+
+			frame = pfn_to_mfn(pfn);
+			set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
+
+			MULTI_update_va_mapping(cr_mcl + j, vstart,
+						pfn_pte_ma(frame, PAGE_KERNEL),
+						UVMF_INVLPG|UVMF_ALL);
+			++j;
+
+			pfn = __pa(vstart) >> PAGE_SHIFT;
+			set_phys_to_machine(pfn, frame);
+			if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+				mmu.ptr = ((uint64_t)frame << PAGE_SHIFT) | MMU_MACHPHYS_UPDATE;
+				mmu.val = pfn;
+				cr_mcl[j].op = __HYPERVISOR_mmu_update;
+				cr_mcl[j].args[0] = (unsigned long)&mmu;
+				cr_mcl[j].args[1] = 1;
+				cr_mcl[j].args[2] = 0;
+				cr_mcl[j].args[3] = DOMID_SELF;
+				++j;
+			}
+
+			cr_mcl[j].op = __HYPERVISOR_memory_op;
+			cr_mcl[j].args[0] = XENMEM_decrease_reservation;
+			cr_mcl[j].args[1] = (unsigned long)&exchange.in;
+
+			if (HYPERVISOR_multicall(cr_mcl, j + 1))
+				BUG();
+			BUG_ON(cr_mcl[j].result != 1);
+			while (j--)
+				BUG_ON(cr_mcl[j].result != 0);
+
+			balloon_unlock(flags);
+
+			free_empty_pages(&page, 1);
+
+			in_frame++;
+			vstart += PAGE_SIZE;
+		}
+	}
 }
 EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
 
--- sle11-2009-08-26.orig/drivers/xen/balloon/balloon.c	2009-08-31 11:47:38.000000000 +0200
+++ sle11-2009-08-26/drivers/xen/balloon/balloon.c	2009-08-31 11:48:33.000000000 +0200
@@ -696,7 +696,7 @@ struct page **alloc_empty_pages_and_page
 	goto out;
 }
 
-void free_empty_pages_and_pagevec(struct page **pagevec, int nr_pages)
+static void _free_empty_pages_and_pagevec(struct page **pagevec, int nr_pages, int free_vec)
 {
 	unsigned long flags;
 	int i;
@@ -707,15 +707,28 @@ void free_empty_pages_and_pagevec(struct
 	balloon_lock(flags);
 	for (i = 0; i < nr_pages; i++) {
 		BUG_ON(page_count(pagevec[i]) != 1);
-		balloon_append(pagevec[i], 0);
+		balloon_append(pagevec[i], !free_vec);
 	}
+	if (!free_vec)
+		totalram_pages = bs.current_pages -= nr_pages;
 	balloon_unlock(flags);
 
-	kfree(pagevec);
+	if (free_vec)
+		kfree(pagevec);
 
 	schedule_work(&balloon_worker);
 }
 
+void free_empty_pages_and_pagevec(struct page **pagevec, int nr_pages)
+{
+	_free_empty_pages_and_pagevec(pagevec, nr_pages, 1);
+}
+
+void free_empty_pages(struct page **pagevec, int nr_pages)
+{
+	_free_empty_pages_and_pagevec(pagevec, nr_pages, 0);
+}
+
 void balloon_release_driver_page(struct page *page)
 {
 	unsigned long flags;
--- sle11-2009-08-26.orig/include/xen/balloon.h	2009-08-31 11:47:04.000000000 +0200
+++ sle11-2009-08-26/include/xen/balloon.h	2009-03-16 16:40:33.000000000 +0100
@@ -47,6 +47,10 @@ void balloon_update_driver_allowance(lon
 struct page **alloc_empty_pages_and_pagevec(int nr_pages);
 void free_empty_pages_and_pagevec(struct page **pagevec, int nr_pages);
 
+/* Free an empty page range (not allocated through
+   alloc_empty_pages_and_pagevec), adding to the balloon. */
+void free_empty_pages(struct page **pagevec, int nr_pages);
+
 void balloon_release_driver_page(struct page *page);
 
 /*
Commit	Line	Data
2cb7cef9 BS	1	Subject: Add fallback when XENMEM_exchange fails to replace contiguous region
	2	From: jbeulich@novell.com
	3	Patch-mainline: obsolete
	4	References: 181869
	5
	6	This avoids losing precious special memory in places where any memory can be
	7	used.
	8
82094b55 AF	9	--- sle11-2009-08-26.orig/arch/x86/mm/hypervisor.c 2009-08-31 11:47:04.000000000 +0200
82094b55 AF	10	+++ sle11-2009-08-26/arch/x86/mm/hypervisor.c 2009-03-30 12:18:24.000000000 +0200
2cb7cef9 BS	11	@@ -42,6 +42,7 @@
	12	#include <xen/interface/memory.h>
	13	#include <linux/module.h>
	14	#include <linux/percpu.h>
	15	+#include <linux/highmem.h>
	16	#include <asm/tlbflush.h>
	17	#include <linux/highmem.h>
	18
	19	@@ -712,6 +713,83 @@ void xen_destroy_contiguous_region(unsig
	20	BUG();
	21
	22	balloon_unlock(flags);
	23	+
	24	+ if (unlikely(!success)) {
	25	+ /* Try hard to get the special memory back to Xen. */
	26	+ exchange.in.extent_order = 0;
	27	+ set_xen_guest_handle(exchange.in.extent_start, &in_frame);
	28	+
	29	+ for (i = 0; i < (1U<<order); i++) {
	30	+ struct page *page = alloc_page(__GFP_HIGHMEM\|__GFP_COLD);
	31	+ unsigned long pfn;
	32	+ mmu_update_t mmu;
	33	+ unsigned int j = 0;
	34	+
	35	+ if (!page) {
	36	+ printk(KERN_WARNING "Xen and kernel out of memory "
	37	+ "while trying to release an order %u "
	38	+ "contiguous region\n", order);
	39	+ break;
	40	+ }
	41	+ pfn = page_to_pfn(page);
	42	+
	43	+ balloon_lock(flags);
	44	+
	45	+ if (!PageHighMem(page)) {
	46	+ void *v = __va(pfn << PAGE_SHIFT);
	47	+
	48	+ scrub_pages(v, 1);
	49	+ MULTI_update_va_mapping(cr_mcl + j, (unsigned long)v,
	50	+ __pte_ma(0), UVMF_INVLPG\|UVMF_ALL);
	51	+ ++j;
	52	+ }
	53	+#ifdef CONFIG_XEN_SCRUB_PAGES
	54	+ else {
	55	+ scrub_pages(kmap(page), 1);
	56	+ kunmap(page);
	57	+ kmap_flush_unused();
	58	+ }
	59	+#endif
	60	+
	61	+ frame = pfn_to_mfn(pfn);
	62	+ set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
	63	+
	64	+ MULTI_update_va_mapping(cr_mcl + j, vstart,
	65	+ pfn_pte_ma(frame, PAGE_KERNEL),
	66	+ UVMF_INVLPG\|UVMF_ALL);
	67	+ ++j;
	68	+
	69	+ pfn = __pa(vstart) >> PAGE_SHIFT;
	70	+ set_phys_to_machine(pfn, frame);
	71	+ if (!xen_feature(XENFEAT_auto_translated_physmap)) {
	72	+ mmu.ptr = ((uint64_t)frame << PAGE_SHIFT) \| MMU_MACHPHYS_UPDATE;
	73	+ mmu.val = pfn;
	74	+ cr_mcl[j].op = __HYPERVISOR_mmu_update;
75	+ cr_mcl[j].args[0] = (unsigned long)&mmu;
76	+ cr_mcl[j].args[1] = 1;
77	+ cr_mcl[j].args[2] = 0;
78	+ cr_mcl[j].args[3] = DOMID_SELF;
79	+ ++j;
80	+ }
81	+
82	+ cr_mcl[j].op = __HYPERVISOR_memory_op;
83	+ cr_mcl[j].args[0] = XENMEM_decrease_reservation;
84	+ cr_mcl[j].args[1] = (unsigned long)&exchange.in;
85	+
86	+ if (HYPERVISOR_multicall(cr_mcl, j + 1))
87	+ BUG();
88	+ BUG_ON(cr_mcl[j].result != 1);
89	+ while (j--)
90	+ BUG_ON(cr_mcl[j].result != 0);
91	+
92	+ balloon_unlock(flags);
93	+
94	+ free_empty_pages(&page, 1);
95	+
96	+ in_frame++;
97	+ vstart += PAGE_SIZE;
98	+ }
99	+ }
100	}
101	EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
102
82094b55 AF	103	--- sle11-2009-08-26.orig/drivers/xen/balloon/balloon.c 2009-08-31 11:47:38.000000000 +0200
	104	+++ sle11-2009-08-26/drivers/xen/balloon/balloon.c 2009-08-31 11:48:33.000000000 +0200
	105	@@ -696,7 +696,7 @@ struct page **alloc_empty_pages_and_page
2cb7cef9 BS	106	goto out;
	107	}
	108
	109	-void free_empty_pages_and_pagevec(struct page **pagevec, int nr_pages)
	110	+static void _free_empty_pages_and_pagevec(struct page **pagevec, int nr_pages, int free_vec)
	111	{
	112	unsigned long flags;
	113	int i;
82094b55 AF	114	@@ -707,15 +707,28 @@ void free_empty_pages_and_pagevec(struct
	115	balloon_lock(flags);
	116	for (i = 0; i < nr_pages; i++) {
2cb7cef9	117	BUG_ON(page_count(pagevec[i]) != 1);
82094b55 AF	118	- balloon_append(pagevec[i], 0);
82094b55 AF	119	+ balloon_append(pagevec[i], !free_vec);
2cb7cef9 BS	120	}
	121	+ if (!free_vec)
	122	+ totalram_pages = bs.current_pages -= nr_pages;
	123	balloon_unlock(flags);
	124
	125	- kfree(pagevec);
	126	+ if (free_vec)
	127	+ kfree(pagevec);
	128
	129	schedule_work(&balloon_worker);
	130	}
	131
	132	+void free_empty_pages_and_pagevec(struct page **pagevec, int nr_pages)
	133	+{
	134	+ _free_empty_pages_and_pagevec(pagevec, nr_pages, 1);
	135	+}
	136	+
	137	+void free_empty_pages(struct page **pagevec, int nr_pages)
	138	+{
	139	+ _free_empty_pages_and_pagevec(pagevec, nr_pages, 0);
	140	+}
	141	+
	142	void balloon_release_driver_page(struct page *page)
	143	{
	144	unsigned long flags;
82094b55 AF	145	--- sle11-2009-08-26.orig/include/xen/balloon.h 2009-08-31 11:47:04.000000000 +0200
82094b55 AF	146	+++ sle11-2009-08-26/include/xen/balloon.h 2009-03-16 16:40:33.000000000 +0100
2cb7cef9 BS	147	@@ -47,6 +47,10 @@ void balloon_update_driver_allowance(lon
	148	struct page **alloc_empty_pages_and_pagevec(int nr_pages);
	149	void free_empty_pages_and_pagevec(struct page **pagevec, int nr_pages);
	150
	151	+/* Free an empty page range (not allocated through
	152	+ alloc_empty_pages_and_pagevec), adding to the balloon. */
	153	+void free_empty_pages(struct page **pagevec, int nr_pages);
	154	+
	155	void balloon_release_driver_page(struct page *page);
	156
	157	/*