From 3bcd0662d66fd07e596d2a7445e6b3215631b901 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Fri, 30 Jul 2021 18:04:52 -0400 Subject: KVM: X86: Introduce mmu_rmaps_stat per-vm debugfs file Use this file to dump rmap statistic information. The statistic is done by calculating the rmap count and the result is log-2-based. An example output of this looks like (idle 6GB guest, right after boot linux): Rmap_Count: 0 1 2-3 4-7 8-15 16-31 32-63 64-127 128-255 256-511 512-1023 Level=4K: 3086676 53045 12330 1272 502 121 76 2 0 0 0 Level=2M: 5947 231 0 0 0 0 0 0 0 0 0 Level=1G: 32 0 0 0 0 0 0 0 0 0 0 Signed-off-by: Peter Xu Message-Id: <20210730220455.26054-5-peterx@redhat.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/debugfs.c | 111 ++++++++++++++++++++++++++++++++++++++++ arch/x86/kvm/mmu/mmu.c | 20 ++++++++ arch/x86/kvm/mmu/mmu_internal.h | 1 + 3 files changed, 132 insertions(+) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/debugfs.c b/arch/x86/kvm/debugfs.c index 95a98413dc32..54a83a744538 100644 --- a/arch/x86/kvm/debugfs.c +++ b/arch/x86/kvm/debugfs.c @@ -7,6 +7,8 @@ #include #include #include "lapic.h" +#include "mmu.h" +#include "mmu/mmu_internal.h" static int vcpu_get_timer_advance_ns(void *data, u64 *val) { @@ -73,3 +75,112 @@ void kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu, struct dentry *debugfs_ &vcpu_tsc_scaling_frac_fops); } } + +/* + * This covers statistics <1024 (11=log(1024)+1), which should be enough to + * cover RMAP_RECYCLE_THRESHOLD. + */ +#define RMAP_LOG_SIZE 11 + +static const char *kvm_lpage_str[KVM_NR_PAGE_SIZES] = { "4K", "2M", "1G" }; + +static int kvm_mmu_rmaps_stat_show(struct seq_file *m, void *v) +{ + struct kvm_rmap_head *rmap; + struct kvm *kvm = m->private; + struct kvm_memory_slot *slot; + struct kvm_memslots *slots; + unsigned int lpage_size, index; + /* Still small enough to be on the stack */ + unsigned int *log[KVM_NR_PAGE_SIZES], *cur; + int i, j, k, l, ret; + + ret = -ENOMEM; + memset(log, 0, sizeof(log)); + for (i = 0; i < KVM_NR_PAGE_SIZES; i++) { + log[i] = kcalloc(RMAP_LOG_SIZE, sizeof(unsigned int), GFP_KERNEL); + if (!log[i]) + goto out; + } + + mutex_lock(&kvm->slots_lock); + write_lock(&kvm->mmu_lock); + + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + slots = __kvm_memslots(kvm, i); + for (j = 0; j < slots->used_slots; j++) { + slot = &slots->memslots[j]; + for (k = 0; k < KVM_NR_PAGE_SIZES; k++) { + rmap = slot->arch.rmap[k]; + lpage_size = kvm_mmu_slot_lpages(slot, k + 1); + cur = log[k]; + for (l = 0; l < lpage_size; l++) { + index = ffs(pte_list_count(&rmap[l])); + if (WARN_ON_ONCE(index >= RMAP_LOG_SIZE)) + index = RMAP_LOG_SIZE - 1; + cur[index]++; + } + } + } + } + + write_unlock(&kvm->mmu_lock); + mutex_unlock(&kvm->slots_lock); + + /* index=0 counts no rmap; index=1 counts 1 rmap */ + seq_printf(m, "Rmap_Count:\t0\t1\t"); + for (i = 2; i < RMAP_LOG_SIZE; i++) { + j = 1 << (i - 1); + k = (1 << i) - 1; + seq_printf(m, "%d-%d\t", j, k); + } + seq_printf(m, "\n"); + + for (i = 0; i < KVM_NR_PAGE_SIZES; i++) { + seq_printf(m, "Level=%s:\t", kvm_lpage_str[i]); + cur = log[i]; + for (j = 0; j < RMAP_LOG_SIZE; j++) + seq_printf(m, "%d\t", cur[j]); + seq_printf(m, "\n"); + } + + ret = 0; +out: + for (i = 0; i < KVM_NR_PAGE_SIZES; i++) + kfree(log[i]); + + return ret; +} + +static int kvm_mmu_rmaps_stat_open(struct inode *inode, struct file *file) +{ + struct kvm *kvm = inode->i_private; + + if (!kvm_get_kvm_safe(kvm)) + return -ENOENT; + + return single_open(file, kvm_mmu_rmaps_stat_show, kvm); +} + +static int kvm_mmu_rmaps_stat_release(struct inode *inode, struct file *file) +{ + struct kvm *kvm = inode->i_private; + + kvm_put_kvm(kvm); + + return single_release(inode, file); +} + +static const struct file_operations mmu_rmaps_stat_fops = { + .open = kvm_mmu_rmaps_stat_open, + .read = seq_read, + .llseek = seq_lseek, + .release = kvm_mmu_rmaps_stat_release, +}; + +int kvm_arch_create_vm_debugfs(struct kvm *kvm) +{ + debugfs_create_file("mmu_rmaps_stat", 0644, kvm->debugfs_dentry, kvm, + &mmu_rmaps_stat_fops); + return 0; +} diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index d282ccf5f0c5..5daa8a910e8b 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1035,6 +1035,26 @@ out: return true; } +unsigned int pte_list_count(struct kvm_rmap_head *rmap_head) +{ + struct pte_list_desc *desc; + unsigned int count = 0; + + if (!rmap_head->val) + return 0; + else if (!(rmap_head->val & 1)) + return 1; + + desc = (struct pte_list_desc *)(rmap_head->val & ~1ul); + + while (desc) { + count += desc->spte_count; + desc = desc->more; + } + + return count; +} + static struct kvm_rmap_head *gfn_to_rmap(gfn_t gfn, int level, const struct kvm_memory_slot *slot) { diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h index ca7b7595bbfc..62bb8f758b3f 100644 --- a/arch/x86/kvm/mmu/mmu_internal.h +++ b/arch/x86/kvm/mmu/mmu_internal.h @@ -131,6 +131,7 @@ bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm, int min_level); void kvm_flush_remote_tlbs_with_address(struct kvm *kvm, u64 start_gfn, u64 pages); +unsigned int pte_list_count(struct kvm_rmap_head *rmap_head); /* * Return values of handle_mmio_page_fault, mmu.page_fault, and fast_page_fault(). -- cgit v1.2.3-59-g8ed1b