| Message ID | 20210624181356.10235-7-peterx@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: X86: Some light optimizations on rmap logic | expand |
On Thu, Jun 24, 2021 at 02:13:53PM -0400, Peter Xu wrote: > Use this file to dump rmap statistic information. I should still paste some example output here in commit message, which I think could help on review but I forgot.. There's actually a example in another commit message, but still, it looks like this (6G guest): # cat mmu_rmaps_stat Rmap_Count: 0 1 2-3 4-7 8-15 16-31 32-63 64-127 128-255 256-511 512-1023 Level=4K: 3089171 49005 14016 1363 235 212 15 7 0 0 0 Level=2M: 5951 227 0 0 0 0 0 0 0 0 0 Level=1G: 32 0 0 0 0 0 0 0 0 0 0 We've got another smm address spaces so it's just got doubled. I'll append that into commit message in the new version (as long as I don't get a NAK on this patch). > > Signed-off-by: Peter Xu <peterx@redhat.com> > --- > arch/x86/kvm/x86.c | 113 +++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 113 insertions(+) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index d2acbea2f3b5..6dfae8375c44 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -30,6 +30,7 @@ > #include "hyperv.h" > #include "lapic.h" > #include "xen.h" > +#include "mmu/mmu_internal.h" > > #include <linux/clocksource.h> > #include <linux/interrupt.h> > @@ -58,6 +59,7 @@ > #include <linux/sched/isolation.h> > #include <linux/mem_encrypt.h> > #include <linux/entry-kvm.h> > +#include <linux/debugfs.h> > > #include <trace/events/kvm.h> > > @@ -10763,6 +10765,117 @@ int kvm_arch_post_init_vm(struct kvm *kvm) > return kvm_mmu_post_init_vm(kvm); > } > > +/* > + * 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; > + > + memset(log, 0, sizeof(log)); > + > + ret = -ENOMEM; > + for (i = 0; i < KVM_NR_PAGE_SIZES; i++) { > + log[i] = kzalloc(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++) > + if (log[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; > +} > + > static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu) > { > vcpu_load(vcpu); > -- > 2.31.1 >
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d2acbea2f3b5..6dfae8375c44 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -30,6 +30,7 @@ #include "hyperv.h" #include "lapic.h" #include "xen.h" +#include "mmu/mmu_internal.h" #include <linux/clocksource.h> #include <linux/interrupt.h> @@ -58,6 +59,7 @@ #include <linux/sched/isolation.h> #include <linux/mem_encrypt.h> #include <linux/entry-kvm.h> +#include <linux/debugfs.h> #include <trace/events/kvm.h> @@ -10763,6 +10765,117 @@ int kvm_arch_post_init_vm(struct kvm *kvm) return kvm_mmu_post_init_vm(kvm); } +/* + * 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; + + memset(log, 0, sizeof(log)); + + ret = -ENOMEM; + for (i = 0; i < KVM_NR_PAGE_SIZES; i++) { + log[i] = kzalloc(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++) + if (log[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; +} + static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu) { vcpu_load(vcpu);
Use this file to dump rmap statistic information. Signed-off-by: Peter Xu <peterx@redhat.com> --- arch/x86/kvm/x86.c | 113 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 113 insertions(+)