X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=arch%2Fx86%2Fxen%2Fmmu.c;h=f5af913fd7b0b6f0c50c0424be067d7bf36f9af3;hb=994025caba3e6beade9bde84dd1b70d9d250f27b;hp=aa37469da69691cba0eca23089a517dcab26351a;hpb=3859069bc3358772b08bd91efe9edec39a746ea8;p=linux-2.6-omap-h63xx.git

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index aa37469da69..f5af913fd7b 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -40,6 +40,7 @@
  */
 #include <linux/sched.h>
 #include <linux/highmem.h>
+#include <linux/debugfs.h>
 #include <linux/bug.h>
 
 #include <asm/pgtable.h>
@@ -57,6 +58,61 @@
 
 #include "multicalls.h"
 #include "mmu.h"
+#include "debugfs.h"
+
+#define MMU_UPDATE_HISTO	30
+
+#ifdef CONFIG_XEN_DEBUG_FS
+
+static struct {
+	u32 pgd_update;
+	u32 pgd_update_pinned;
+	u32 pgd_update_batched;
+
+	u32 pud_update;
+	u32 pud_update_pinned;
+	u32 pud_update_batched;
+
+	u32 pmd_update;
+	u32 pmd_update_pinned;
+	u32 pmd_update_batched;
+
+	u32 pte_update;
+	u32 pte_update_pinned;
+	u32 pte_update_batched;
+
+	u32 mmu_update;
+	u32 mmu_update_extended;
+	u32 mmu_update_histo[MMU_UPDATE_HISTO];
+
+	u32 prot_commit;
+	u32 prot_commit_batched;
+
+	u32 set_pte_at;
+	u32 set_pte_at_batched;
+	u32 set_pte_at_pinned;
+	u32 set_pte_at_current;
+	u32 set_pte_at_kernel;
+} mmu_stats;
+
+static u8 zero_stats;
+
+static inline void check_zero(void)
+{
+	if (unlikely(zero_stats)) {
+		memset(&mmu_stats, 0, sizeof(mmu_stats));
+		zero_stats = 0;
+	}
+}
+
+#define ADD_STATS(elem, val)			\
+	do { check_zero(); mmu_stats.elem += (val); } while(0)
+
+#else  /* !CONFIG_XEN_DEBUG_FS */
+
+#define ADD_STATS(elem, val)	do { (void)(val); } while(0)
+
+#endif /* CONFIG_XEN_DEBUG_FS */
 
 /*
  * Just beyond the highest usermode address.  STACK_TOP_MAX has a
@@ -229,25 +285,35 @@ void make_lowmem_page_readwrite(void *vaddr)
 }
 
 
-static bool page_pinned(void *ptr)
+static bool xen_page_pinned(void *ptr)
 {
 	struct page *page = virt_to_page(ptr);
 
 	return PagePinned(page);
 }
 
-static void extend_mmu_update(const struct mmu_update *update)
+static void xen_extend_mmu_update(const struct mmu_update *update)
 {
 	struct multicall_space mcs;
 	struct mmu_update *u;
 
 	mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
 
-	if (mcs.mc != NULL)
+	if (mcs.mc != NULL) {
+		ADD_STATS(mmu_update_extended, 1);
+		ADD_STATS(mmu_update_histo[mcs.mc->args[1]], -1);
+
 		mcs.mc->args[1]++;
-	else {
+
+		if (mcs.mc->args[1] < MMU_UPDATE_HISTO)
+			ADD_STATS(mmu_update_histo[mcs.mc->args[1]], 1);
+		else
+			ADD_STATS(mmu_update_histo[0], 1);
+	} else {
+		ADD_STATS(mmu_update, 1);
 		mcs = __xen_mc_entry(sizeof(*u));
 		MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
+		ADD_STATS(mmu_update_histo[1], 1);
 	}
 
 	u = mcs.args;
@@ -265,7 +331,9 @@ void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
 	/* ptr may be ioremapped for 64-bit pagetable setup */
 	u.ptr = arbitrary_virt_to_machine(ptr).maddr;
 	u.val = pmd_val_ma(val);
-	extend_mmu_update(&u);
+	xen_extend_mmu_update(&u);
+
+	ADD_STATS(pmd_update_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);
 
 	xen_mc_issue(PARAVIRT_LAZY_MMU);
 
@@ -274,13 +342,17 @@ void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
 
 void xen_set_pmd(pmd_t *ptr, pmd_t val)
 {
+	ADD_STATS(pmd_update, 1);
+
 	/* If page is not pinned, we can just update the entry
 	   directly */
-	if (!page_pinned(ptr)) {
+	if (!xen_page_pinned(ptr)) {
 		*ptr = val;
 		return;
 	}
 
+	ADD_STATS(pmd_update_pinned, 1);
+
 	xen_set_pmd_hyper(ptr, val);
 }
 
@@ -300,12 +372,18 @@ void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
 	if (mm == &init_mm)
 		preempt_disable();
 
+	ADD_STATS(set_pte_at, 1);
+//	ADD_STATS(set_pte_at_pinned, xen_page_pinned(ptep));
+	ADD_STATS(set_pte_at_current, mm == current->mm);
+	ADD_STATS(set_pte_at_kernel, mm == &init_mm);
+
 	if (mm == current->mm || mm == &init_mm) {
 		if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
 			struct multicall_space mcs;
 			mcs = xen_mc_entry(0);
 
 			MULTI_update_va_mapping(mcs.mc, addr, pteval, 0);
+			ADD_STATS(set_pte_at_batched, 1);
 			xen_mc_issue(PARAVIRT_LAZY_MMU);
 			goto out;
 		} else
@@ -334,7 +412,10 @@ void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
 
 	u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
 	u.val = pte_val_ma(pte);
-	extend_mmu_update(&u);
+	xen_extend_mmu_update(&u);
+
+	ADD_STATS(prot_commit, 1);
+	ADD_STATS(prot_commit_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);
 
 	xen_mc_issue(PARAVIRT_LAZY_MMU);
 }
@@ -400,7 +481,9 @@ void xen_set_pud_hyper(pud_t *ptr, pud_t val)
 	/* ptr may be ioremapped for 64-bit pagetable setup */
 	u.ptr = arbitrary_virt_to_machine(ptr).maddr;
 	u.val = pud_val_ma(val);
-	extend_mmu_update(&u);
+	xen_extend_mmu_update(&u);
+
+	ADD_STATS(pud_update_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);
 
 	xen_mc_issue(PARAVIRT_LAZY_MMU);
 
@@ -409,18 +492,26 @@ void xen_set_pud_hyper(pud_t *ptr, pud_t val)
 
 void xen_set_pud(pud_t *ptr, pud_t val)
 {
+	ADD_STATS(pud_update, 1);
+
 	/* If page is not pinned, we can just update the entry
 	   directly */
-	if (!page_pinned(ptr)) {
+	if (!xen_page_pinned(ptr)) {
 		*ptr = val;
 		return;
 	}
 
+	ADD_STATS(pud_update_pinned, 1);
+
 	xen_set_pud_hyper(ptr, val);
 }
 
 void xen_set_pte(pte_t *ptep, pte_t pte)
 {
+	ADD_STATS(pte_update, 1);
+//	ADD_STATS(pte_update_pinned, xen_page_pinned(ptep));
+	ADD_STATS(pte_update_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);
+
 #ifdef CONFIG_X86_PAE
 	ptep->pte_high = pte.pte_high;
 	smp_wmb();
@@ -490,7 +581,7 @@ static void __xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
 
 	u.ptr = virt_to_machine(ptr).maddr;
 	u.val = pgd_val_ma(val);
-	extend_mmu_update(&u);
+	xen_extend_mmu_update(&u);
 }
 
 /*
@@ -517,17 +608,22 @@ void xen_set_pgd(pgd_t *ptr, pgd_t val)
 {
 	pgd_t *user_ptr = xen_get_user_pgd(ptr);
 
+	ADD_STATS(pgd_update, 1);
+
 	/* If page is not pinned, we can just update the entry
 	   directly */
-	if (!page_pinned(ptr)) {
+	if (!xen_page_pinned(ptr)) {
 		*ptr = val;
 		if (user_ptr) {
-			WARN_ON(page_pinned(user_ptr));
+			WARN_ON(xen_page_pinned(user_ptr));
 			*user_ptr = val;
 		}
 		return;
 	}
 
+	ADD_STATS(pgd_update_pinned, 1);
+	ADD_STATS(pgd_update_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);
+
 	/* If it's pinned, then we can at least batch the kernel and
 	   user updates together. */
 	xen_mc_batch();
@@ -555,8 +651,8 @@ void xen_set_pgd(pgd_t *ptr, pgd_t val)
  * For 64-bit, we must skip the Xen hole in the middle of the address
  * space, just after the big x86-64 virtual hole.
  */
-static int pgd_walk(pgd_t *pgd, int (*func)(struct page *, enum pt_level),
-		    unsigned long limit)
+static int xen_pgd_walk(pgd_t *pgd, int (*func)(struct page *, enum pt_level),
+			unsigned long limit)
 {
 	int flush = 0;
 	unsigned hole_low, hole_high;
@@ -590,8 +686,6 @@ static int pgd_walk(pgd_t *pgd, int (*func)(struct page *, enum pt_level),
 	pmdidx_limit = 0;
 #endif
 
-	flush |= (*func)(virt_to_page(pgd), PT_PGD);
-
 	for (pgdidx = 0; pgdidx <= pgdidx_limit; pgdidx++) {
 		pud_t *pud;
 
@@ -637,12 +731,18 @@ static int pgd_walk(pgd_t *pgd, int (*func)(struct page *, enum pt_level),
 			}
 		}
 	}
+
 out:
+	/* Do the top level last, so that the callbacks can use it as
+	   a cue to do final things like tlb flushes. */
+	flush |= (*func)(virt_to_page(pgd), PT_PGD);
 
 	return flush;
 }
 
-static spinlock_t *lock_pte(struct page *page)
+/* If we're using split pte locks, then take the page's lock and
+   return a pointer to it.  Otherwise return NULL. */
+static spinlock_t *xen_pte_lock(struct page *page)
 {
 	spinlock_t *ptl = NULL;
 
@@ -654,7 +754,7 @@ static spinlock_t *lock_pte(struct page *page)
 	return ptl;
 }
 
-static void do_unlock(void *v)
+static void xen_pte_unlock(void *v)
 {
 	spinlock_t *ptl = v;
 	spin_unlock(ptl);
@@ -672,7 +772,7 @@ static void xen_do_pin(unsigned level, unsigned long pfn)
 	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 }
 
-static int pin_page(struct page *page, enum pt_level level)
+static int xen_pin_page(struct page *page, enum pt_level level)
 {
 	unsigned pgfl = TestSetPagePinned(page);
 	int flush;
@@ -691,21 +791,40 @@ static int pin_page(struct page *page, enum pt_level level)
 
 		flush = 0;
 
+		/*
+		 * We need to hold the pagetable lock between the time
+		 * we make the pagetable RO and when we actually pin
+		 * it.  If we don't, then other users may come in and
+		 * attempt to update the pagetable by writing it,
+		 * which will fail because the memory is RO but not
+		 * pinned, so Xen won't do the trap'n'emulate.
+		 *
+		 * If we're using split pte locks, we can't hold the
+		 * entire pagetable's worth of locks during the
+		 * traverse, because we may wrap the preempt count (8
+		 * bits).  The solution is to mark RO and pin each PTE
+		 * page while holding the lock.  This means the number
+		 * of locks we end up holding is never more than a
+		 * batch size (~32 entries, at present).
+		 *
+		 * If we're not using split pte locks, we needn't pin
+		 * the PTE pages independently, because we're
+		 * protected by the overall pagetable lock.
+		 */
 		ptl = NULL;
 		if (level == PT_PTE)
-			ptl = lock_pte(page);
+			ptl = xen_pte_lock(page);
 
 		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
 					pfn_pte(pfn, PAGE_KERNEL_RO),
 					level == PT_PGD ? UVMF_TLB_FLUSH : 0);
 
-		if (level == PT_PTE)
+		if (ptl) {
 			xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);
 
-		if (ptl) {
 			/* Queue a deferred unlock for when this batch
 			   is completed. */
-			xen_mc_callback(do_unlock, ptl);
+			xen_mc_callback(xen_pte_unlock, ptl);
 		}
 	}
 
@@ -719,7 +838,7 @@ void xen_pgd_pin(pgd_t *pgd)
 {
 	xen_mc_batch();
 
-	if (pgd_walk(pgd, pin_page, USER_LIMIT)) {
+	if (xen_pgd_walk(pgd, xen_pin_page, USER_LIMIT)) {
 		/* re-enable interrupts for kmap_flush_unused */
 		xen_mc_issue(0);
 		kmap_flush_unused();
@@ -733,14 +852,14 @@ void xen_pgd_pin(pgd_t *pgd)
 		xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));
 
 		if (user_pgd) {
-			pin_page(virt_to_page(user_pgd), PT_PGD);
+			xen_pin_page(virt_to_page(user_pgd), PT_PGD);
 			xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(user_pgd)));
 		}
 	}
 #else /* CONFIG_X86_32 */
 #ifdef CONFIG_X86_PAE
 	/* Need to make sure unshared kernel PMD is pinnable */
-	pin_page(virt_to_page(pgd_page(pgd[pgd_index(TASK_SIZE)])), PT_PMD);
+	xen_pin_page(virt_to_page(pgd_page(pgd[pgd_index(TASK_SIZE)])), PT_PMD);
 #endif
 	xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
 #endif /* CONFIG_X86_64 */
@@ -775,7 +894,7 @@ void xen_mm_pin_all(void)
  * that's before we have page structures to store the bits.  So do all
  * the book-keeping now.
  */
-static __init int mark_pinned(struct page *page, enum pt_level level)
+static __init int xen_mark_pinned(struct page *page, enum pt_level level)
 {
 	SetPagePinned(page);
 	return 0;
@@ -783,10 +902,10 @@ static __init int mark_pinned(struct page *page, enum pt_level level)
 
 void __init xen_mark_init_mm_pinned(void)
 {
-	pgd_walk(init_mm.pgd, mark_pinned, FIXADDR_TOP);
+	xen_pgd_walk(init_mm.pgd, xen_mark_pinned, FIXADDR_TOP);
 }
 
-static int unpin_page(struct page *page, enum pt_level level)
+static int xen_unpin_page(struct page *page, enum pt_level level)
 {
 	unsigned pgfl = TestClearPagePinned(page);
 
@@ -796,10 +915,18 @@ static int unpin_page(struct page *page, enum pt_level level)
 		spinlock_t *ptl = NULL;
 		struct multicall_space mcs;
 
+		/*
+		 * Do the converse to pin_page.  If we're using split
+		 * pte locks, we must be holding the lock for while
+		 * the pte page is unpinned but still RO to prevent
+		 * concurrent updates from seeing it in this
+		 * partially-pinned state.
+		 */
 		if (level == PT_PTE) {
-			ptl = lock_pte(page);
+			ptl = xen_pte_lock(page);
 
-			xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
+			if (ptl)
+				xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
 		}
 
 		mcs = __xen_mc_entry(0);
@@ -810,7 +937,7 @@ static int unpin_page(struct page *page, enum pt_level level)
 
 		if (ptl) {
 			/* unlock when batch completed */
-			xen_mc_callback(do_unlock, ptl);
+			xen_mc_callback(xen_pte_unlock, ptl);
 		}
 	}
 
@@ -830,17 +957,17 @@ static void xen_pgd_unpin(pgd_t *pgd)
 
 		if (user_pgd) {
 			xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(user_pgd)));
-			unpin_page(virt_to_page(user_pgd), PT_PGD);
+			xen_unpin_page(virt_to_page(user_pgd), PT_PGD);
 		}
 	}
 #endif
 
 #ifdef CONFIG_X86_PAE
 	/* Need to make sure unshared kernel PMD is unpinned */
-	pin_page(virt_to_page(pgd_page(pgd[pgd_index(TASK_SIZE)])), PT_PMD);
+	xen_unpin_page(virt_to_page(pgd_page(pgd[pgd_index(TASK_SIZE)])), PT_PMD);
 #endif
 
-	pgd_walk(pgd, unpin_page, USER_LIMIT);
+	xen_pgd_walk(pgd, xen_unpin_page, USER_LIMIT);
 
 	xen_mc_issue(0);
 }
@@ -907,7 +1034,7 @@ static void drop_other_mm_ref(void *info)
 	}
 }
 
-static void drop_mm_ref(struct mm_struct *mm)
+static void xen_drop_mm_ref(struct mm_struct *mm)
 {
 	cpumask_t mask;
 	unsigned cpu;
@@ -937,7 +1064,7 @@ static void drop_mm_ref(struct mm_struct *mm)
 		smp_call_function_mask(mask, drop_other_mm_ref, mm, 1);
 }
 #else
-static void drop_mm_ref(struct mm_struct *mm)
+static void xen_drop_mm_ref(struct mm_struct *mm)
 {
 	if (current->active_mm == mm)
 		load_cr3(swapper_pg_dir);
@@ -961,14 +1088,77 @@ static void drop_mm_ref(struct mm_struct *mm)
 void xen_exit_mmap(struct mm_struct *mm)
 {
 	get_cpu();		/* make sure we don't move around */
-	drop_mm_ref(mm);
+	xen_drop_mm_ref(mm);
 	put_cpu();
 
 	spin_lock(&mm->page_table_lock);
 
 	/* pgd may not be pinned in the error exit path of execve */
-	if (page_pinned(mm->pgd))
+	if (xen_page_pinned(mm->pgd))
 		xen_pgd_unpin(mm->pgd);
 
 	spin_unlock(&mm->page_table_lock);
 }
+
+#ifdef CONFIG_XEN_DEBUG_FS
+
+static struct dentry *d_mmu_debug;
+
+static int __init xen_mmu_debugfs(void)
+{
+	struct dentry *d_xen = xen_init_debugfs();
+
+	if (d_xen == NULL)
+		return -ENOMEM;
+
+	d_mmu_debug = debugfs_create_dir("mmu", d_xen);
+
+	debugfs_create_u8("zero_stats", 0644, d_mmu_debug, &zero_stats);
+
+	debugfs_create_u32("pgd_update", 0444, d_mmu_debug, &mmu_stats.pgd_update);
+	debugfs_create_u32("pgd_update_pinned", 0444, d_mmu_debug,
+			   &mmu_stats.pgd_update_pinned);
+	debugfs_create_u32("pgd_update_batched", 0444, d_mmu_debug,
+			   &mmu_stats.pgd_update_pinned);
+
+	debugfs_create_u32("pud_update", 0444, d_mmu_debug, &mmu_stats.pud_update);
+	debugfs_create_u32("pud_update_pinned", 0444, d_mmu_debug,
+			   &mmu_stats.pud_update_pinned);
+	debugfs_create_u32("pud_update_batched", 0444, d_mmu_debug,
+			   &mmu_stats.pud_update_pinned);
+
+	debugfs_create_u32("pmd_update", 0444, d_mmu_debug, &mmu_stats.pmd_update);
+	debugfs_create_u32("pmd_update_pinned", 0444, d_mmu_debug,
+			   &mmu_stats.pmd_update_pinned);
+	debugfs_create_u32("pmd_update_batched", 0444, d_mmu_debug,
+			   &mmu_stats.pmd_update_pinned);
+
+	debugfs_create_u32("pte_update", 0444, d_mmu_debug, &mmu_stats.pte_update);
+//	debugfs_create_u32("pte_update_pinned", 0444, d_mmu_debug,
+//			   &mmu_stats.pte_update_pinned);
+	debugfs_create_u32("pte_update_batched", 0444, d_mmu_debug,
+			   &mmu_stats.pte_update_pinned);
+
+	debugfs_create_u32("mmu_update", 0444, d_mmu_debug, &mmu_stats.mmu_update);
+	debugfs_create_u32("mmu_update_extended", 0444, d_mmu_debug,
+			   &mmu_stats.mmu_update_extended);
+	xen_debugfs_create_u32_array("mmu_update_histo", 0444, d_mmu_debug,
+				     mmu_stats.mmu_update_histo, 20);
+
+	debugfs_create_u32("set_pte_at", 0444, d_mmu_debug, &mmu_stats.set_pte_at);
+	debugfs_create_u32("set_pte_at_batched", 0444, d_mmu_debug,
+			   &mmu_stats.set_pte_at_batched);
+	debugfs_create_u32("set_pte_at_current", 0444, d_mmu_debug,
+			   &mmu_stats.set_pte_at_current);
+	debugfs_create_u32("set_pte_at_kernel", 0444, d_mmu_debug,
+			   &mmu_stats.set_pte_at_kernel);
+
+	debugfs_create_u32("prot_commit", 0444, d_mmu_debug, &mmu_stats.prot_commit);
+	debugfs_create_u32("prot_commit_batched", 0444, d_mmu_debug,
+			   &mmu_stats.prot_commit_batched);
+
+	return 0;
+}
+fs_initcall(xen_mmu_debugfs);
+
+#endif	/* CONFIG_XEN_DEBUG_FS */