forked from Minki/linux
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 <peterx@redhat.com> Message-Id: <20210730220455.26054-5-peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Peter Xu
Paolo Bonzini
parent
4139b1972a
commit
3bcd0662d6
@ -7,6 +7,8 @@
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#include <linux/kvm_host.h>
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#include <linux/debugfs.h>
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#include "lapic.h"
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#include "mmu.h"
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#include "mmu/mmu_internal.h"
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static int vcpu_get_timer_advance_ns(void *data, u64 *val)
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{
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@ -73,3 +75,112 @@ void kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu, struct dentry *debugfs_
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&vcpu_tsc_scaling_frac_fops);
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}
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}
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/*
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* This covers statistics <1024 (11=log(1024)+1), which should be enough to
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* cover RMAP_RECYCLE_THRESHOLD.
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*/
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#define RMAP_LOG_SIZE 11
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static const char *kvm_lpage_str[KVM_NR_PAGE_SIZES] = { "4K", "2M", "1G" };
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static int kvm_mmu_rmaps_stat_show(struct seq_file *m, void *v)
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{
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struct kvm_rmap_head *rmap;
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struct kvm *kvm = m->private;
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struct kvm_memory_slot *slot;
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struct kvm_memslots *slots;
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unsigned int lpage_size, index;
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/* Still small enough to be on the stack */
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unsigned int *log[KVM_NR_PAGE_SIZES], *cur;
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int i, j, k, l, ret;
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ret = -ENOMEM;
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memset(log, 0, sizeof(log));
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for (i = 0; i < KVM_NR_PAGE_SIZES; i++) {
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log[i] = kcalloc(RMAP_LOG_SIZE, sizeof(unsigned int), GFP_KERNEL);
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if (!log[i])
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goto out;
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}
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mutex_lock(&kvm->slots_lock);
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write_lock(&kvm->mmu_lock);
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for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
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slots = __kvm_memslots(kvm, i);
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for (j = 0; j < slots->used_slots; j++) {
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slot = &slots->memslots[j];
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for (k = 0; k < KVM_NR_PAGE_SIZES; k++) {
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rmap = slot->arch.rmap[k];
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lpage_size = kvm_mmu_slot_lpages(slot, k + 1);
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cur = log[k];
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for (l = 0; l < lpage_size; l++) {
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index = ffs(pte_list_count(&rmap[l]));
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if (WARN_ON_ONCE(index >= RMAP_LOG_SIZE))
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index = RMAP_LOG_SIZE - 1;
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cur[index]++;
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}
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}
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}
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}
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write_unlock(&kvm->mmu_lock);
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mutex_unlock(&kvm->slots_lock);
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/* index=0 counts no rmap; index=1 counts 1 rmap */
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seq_printf(m, "Rmap_Count:\t0\t1\t");
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for (i = 2; i < RMAP_LOG_SIZE; i++) {
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j = 1 << (i - 1);
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k = (1 << i) - 1;
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seq_printf(m, "%d-%d\t", j, k);
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}
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seq_printf(m, "\n");
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for (i = 0; i < KVM_NR_PAGE_SIZES; i++) {
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seq_printf(m, "Level=%s:\t", kvm_lpage_str[i]);
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cur = log[i];
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for (j = 0; j < RMAP_LOG_SIZE; j++)
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seq_printf(m, "%d\t", cur[j]);
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seq_printf(m, "\n");
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}
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ret = 0;
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out:
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for (i = 0; i < KVM_NR_PAGE_SIZES; i++)
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kfree(log[i]);
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return ret;
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}
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static int kvm_mmu_rmaps_stat_open(struct inode *inode, struct file *file)
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{
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struct kvm *kvm = inode->i_private;
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if (!kvm_get_kvm_safe(kvm))
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return -ENOENT;
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return single_open(file, kvm_mmu_rmaps_stat_show, kvm);
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}
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static int kvm_mmu_rmaps_stat_release(struct inode *inode, struct file *file)
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{
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struct kvm *kvm = inode->i_private;
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kvm_put_kvm(kvm);
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return single_release(inode, file);
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}
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static const struct file_operations mmu_rmaps_stat_fops = {
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.open = kvm_mmu_rmaps_stat_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = kvm_mmu_rmaps_stat_release,
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};
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int kvm_arch_create_vm_debugfs(struct kvm *kvm)
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{
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debugfs_create_file("mmu_rmaps_stat", 0644, kvm->debugfs_dentry, kvm,
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&mmu_rmaps_stat_fops);
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return 0;
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}
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@ -1035,6 +1035,26 @@ out:
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return true;
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}
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unsigned int pte_list_count(struct kvm_rmap_head *rmap_head)
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{
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struct pte_list_desc *desc;
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unsigned int count = 0;
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if (!rmap_head->val)
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return 0;
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else if (!(rmap_head->val & 1))
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return 1;
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desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
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while (desc) {
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count += desc->spte_count;
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desc = desc->more;
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}
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return count;
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}
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static struct kvm_rmap_head *gfn_to_rmap(gfn_t gfn, int level,
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const struct kvm_memory_slot *slot)
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{
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@ -131,6 +131,7 @@ bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
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int min_level);
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void kvm_flush_remote_tlbs_with_address(struct kvm *kvm,
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u64 start_gfn, u64 pages);
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unsigned int pte_list_count(struct kvm_rmap_head *rmap_head);
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/*
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* Return values of handle_mmio_page_fault, mmu.page_fault, and fast_page_fault().
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