Commit 3bcd0662 authored by Peter Xu's avatar Peter Xu Committed by Paolo Bonzini

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: default avatarPeter Xu <peterx@redhat.com>
Message-Id: <20210730220455.26054-5-peterx@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 4139b197
......@@ -7,6 +7,8 @@
#include <linux/kvm_host.h>
#include <linux/debugfs.h>
#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;
}
......@@ -1035,6 +1035,26 @@ static bool pte_list_destroy(struct kvm_rmap_head *rmap_head)
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)
{
......
......@@ -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().
......
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