[people/pmueller/ipfire-2.x.git] / src / patches / 60059_xen-x86-dcr-fallback.patch1

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.

Index: head-2008-11-20/arch/x86/mm/hypervisor.c
===================================================================
--- head-2008-11-20.orig/arch/x86/mm/hypervisor.c	2008-11-21 15:51:34.000000000 +0100
+++ head-2008-11-20/arch/x86/mm/hypervisor.c	2008-11-17 12:12:39.000000000 +0100
@@ -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>
 
@@ -668,6 +669,83 @@ 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);
 
Index: head-2008-11-20/drivers/xen/balloon/balloon.c
===================================================================
--- head-2008-11-20.orig/drivers/xen/balloon/balloon.c	2008-11-21 15:56:56.000000000 +0100
+++ head-2008-11-20/drivers/xen/balloon/balloon.c	2008-11-21 16:00:18.000000000 +0100
@@ -687,7 +687,7 @@ 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;
@@ -702,11 +702,24 @@ void free_empty_pages_and_pagevec(struct
 	}
 	balloon_unlock(flags);
 
-	kfree(pagevec);
+	if (free_vec)
+		kfree(pagevec);
+	else
+		totalram_pages = bs.current_pages -= nr_pages;
 
 	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;
Index: head-2008-11-20/include/xen/balloon.h
===================================================================
--- head-2008-11-20.orig/include/xen/balloon.h	2008-11-21 15:51:34.000000000 +0100
+++ head-2008-11-20/include/xen/balloon.h	2008-11-21 09:39:34.000000000 +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
cc90b958 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
	9	Index: head-2008-11-20/arch/x86/mm/hypervisor.c
	10	===================================================================
	11	--- head-2008-11-20.orig/arch/x86/mm/hypervisor.c 2008-11-21 15:51:34.000000000 +0100
	12	+++ head-2008-11-20/arch/x86/mm/hypervisor.c 2008-11-17 12:12:39.000000000 +0100
	13	@@ -42,6 +42,7 @@
	14	#include <xen/interface/memory.h>
	15	#include <linux/module.h>
	16	#include <linux/percpu.h>
	17	+#include <linux/highmem.h>
	18	#include <asm/tlbflush.h>
	19	#include <linux/highmem.h>
	20
	21	@@ -668,6 +669,83 @@ void xen_destroy_contiguous_region(unsig
	22	BUG();
	23
	24	balloon_unlock(flags);
	25	+
	26	+ if (unlikely(!success)) {
	27	+ /* Try hard to get the special memory back to Xen. */
	28	+ exchange.in.extent_order = 0;
	29	+ set_xen_guest_handle(exchange.in.extent_start, &in_frame);
	30	+
	31	+ for (i = 0; i < (1U<<order); i++) {
	32	+ struct page *page = alloc_page(__GFP_HIGHMEM\|__GFP_COLD);
	33	+ unsigned long pfn;
	34	+ mmu_update_t mmu;
	35	+ unsigned int j = 0;
	36	+
	37	+ if (!page) {
	38	+ printk(KERN_WARNING "Xen and kernel out of memory "
	39	+ "while trying to release an order %u "
	40	+ "contiguous region\n", order);
	41	+ break;
	42	+ }
	43	+ pfn = page_to_pfn(page);
	44	+
	45	+ balloon_lock(flags);
	46	+
	47	+ if (!PageHighMem(page)) {
	48	+ void *v = __va(pfn << PAGE_SHIFT);
	49	+
	50	+ scrub_pages(v, 1);
	51	+ MULTI_update_va_mapping(cr_mcl + j, (unsigned long)v,
	52	+ __pte_ma(0), UVMF_INVLPG\|UVMF_ALL);
	53	+ ++j;
	54	+ }
	55	+#ifdef CONFIG_XEN_SCRUB_PAGES
	56	+ else {
	57	+ scrub_pages(kmap(page), 1);
	58	+ kunmap(page);
	59	+ kmap_flush_unused();
	60	+ }
	61	+#endif
	62	+
	63	+ frame = pfn_to_mfn(pfn);
	64	+ set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
65	+
66	+ MULTI_update_va_mapping(cr_mcl + j, vstart,
67	+ pfn_pte_ma(frame, PAGE_KERNEL),
68	+ UVMF_INVLPG\|UVMF_ALL);
69	+ ++j;
70	+
71	+ pfn = __pa(vstart) >> PAGE_SHIFT;
72	+ set_phys_to_machine(pfn, frame);
73	+ if (!xen_feature(XENFEAT_auto_translated_physmap)) {
74	+ mmu.ptr = ((uint64_t)frame << PAGE_SHIFT) \| MMU_MACHPHYS_UPDATE;
75	+ mmu.val = pfn;
76	+ cr_mcl[j].op = __HYPERVISOR_mmu_update;
77	+ cr_mcl[j].args[0] = (unsigned long)&mmu;
78	+ cr_mcl[j].args[1] = 1;
79	+ cr_mcl[j].args[2] = 0;
80	+ cr_mcl[j].args[3] = DOMID_SELF;
81	+ ++j;
82	+ }
83	+
84	+ cr_mcl[j].op = __HYPERVISOR_memory_op;
85	+ cr_mcl[j].args[0] = XENMEM_decrease_reservation;
86	+ cr_mcl[j].args[1] = (unsigned long)&exchange.in;
87	+
88	+ if (HYPERVISOR_multicall(cr_mcl, j + 1))
89	+ BUG();
90	+ BUG_ON(cr_mcl[j].result != 1);
91	+ while (j--)
92	+ BUG_ON(cr_mcl[j].result != 0);
93	+
94	+ balloon_unlock(flags);
95	+
96	+ free_empty_pages(&page, 1);
97	+
98	+ in_frame++;
99	+ vstart += PAGE_SIZE;
100	+ }
101	+ }
102	}
103	EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
104
105	Index: head-2008-11-20/drivers/xen/balloon/balloon.c
106	===================================================================
107	--- head-2008-11-20.orig/drivers/xen/balloon/balloon.c 2008-11-21 15:56:56.000000000 +0100
108	+++ head-2008-11-20/drivers/xen/balloon/balloon.c 2008-11-21 16:00:18.000000000 +0100
109	@@ -687,7 +687,7 @@ struct page **alloc_empty_pages_and_page
110	goto out;
111	}
112
113	-void free_empty_pages_and_pagevec(struct page **pagevec, int nr_pages)
114	+static void _free_empty_pages_and_pagevec(struct page **pagevec, int nr_pages, int free_vec)
115	{
116	unsigned long flags;
117	int i;
118	@@ -702,11 +702,24 @@ void free_empty_pages_and_pagevec(struct
119	}
120	balloon_unlock(flags);
121
122	- kfree(pagevec);
123	+ if (free_vec)
124	+ kfree(pagevec);
125	+ else
126	+ totalram_pages = bs.current_pages -= nr_pages;
127
128	schedule_work(&balloon_worker);
129	}
130
131	+void free_empty_pages_and_pagevec(struct page **pagevec, int nr_pages)
132	+{
133	+ _free_empty_pages_and_pagevec(pagevec, nr_pages, 1);
134	+}
135	+
136	+void free_empty_pages(struct page **pagevec, int nr_pages)
137	+{
138	+ _free_empty_pages_and_pagevec(pagevec, nr_pages, 0);
139	+}
140	+
141	void balloon_release_driver_page(struct page *page)
142	{
143	unsigned long flags;
144	Index: head-2008-11-20/include/xen/balloon.h
145	===================================================================
146	--- head-2008-11-20.orig/include/xen/balloon.h 2008-11-21 15:51:34.000000000 +0100
147	+++ head-2008-11-20/include/xen/balloon.h 2008-11-21 09:39:34.000000000 +0100
148	@@ -47,6 +47,10 @@ void balloon_update_driver_allowance(lon
149	struct page **alloc_empty_pages_and_pagevec(int nr_pages);
150	void free_empty_pages_and_pagevec(struct page **pagevec, int nr_pages);
151
152	+/* Free an empty page range (not allocated through
153	+ alloc_empty_pages_and_pagevec), adding to the balloon. */
154	+void free_empty_pages(struct page **pagevec, int nr_pages);
155	+
156	void balloon_release_driver_page(struct page *page);
157
158	/*