Marcelo Tosatti wrote:
> On Fri, Apr 23, 2010 at 01:58:22PM +0800, Gui Jianfeng wrote:
>> Currently, in kvm_mmu_change_mmu_pages(kvm, page), "used_pages--" is performed after calling
>> kvm_mmu_zap_page() in spite of that whether "page" is actually reclaimed. Because root sp won't
>> be reclaimed by kvm_mmu_zap_page(). So making kvm_mmu_zap_page() return total number of reclaimed
>> sp makes more sense. A new flag is put into kvm_mmu_zap_page() to indicate whether the top page is
>> reclaimed.
>>
>> Signed-off-by: Gui Jianfeng <guijianfeng@xxxxxxxxxxxxxx>
>> ---
>> arch/x86/kvm/mmu.c | 53 +++++++++++++++++++++++++++++++++++----------------
>> 1 files changed, 36 insertions(+), 17 deletions(-)
>
> Gui,
>
> There will be only a few pinned roots, and there is no need for
> kvm_mmu_change_mmu_pages to be precise at that level (pages will be
> reclaimed through kvm_unmap_hva eventually).
Hi Marcelo
Actually, it doesn't only affect kvm_mmu_change_mmu_pages() but also affects kvm_mmu_remove_some_alloc_mmu_pages()
which is called by mmu shrink routine. This will induce upper layer get a wrong number, so i think this should be
fixed. Here is a updated version.
---
From: Gui Jianfeng <guijianfeng@xxxxxxxxxxxxxx>
Currently, in kvm_mmu_change_mmu_pages(kvm, page), "used_pages--" is performed after calling
kvm_mmu_zap_page() in spite of that whether "page" is actually reclaimed. Because root sp won't
be reclaimed by kvm_mmu_zap_page(). So making kvm_mmu_zap_page() return total number of reclaimed
sp makes more sense. A new flag is put into kvm_mmu_zap_page() to indicate whether the top page is
reclaimed. kvm_mmu_remove_some_alloc_mmu_pages() also rely on kvm_mmu_zap_page() to return a total
relcaimed number.
Signed-off-by: Gui Jianfeng <guijianfeng@xxxxxxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 53 +++++++++++++++++++++++++++++++++++----------------
1 files changed, 36 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 51eb6d6..e545da8 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1194,12 +1194,13 @@ static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
--kvm->stat.mmu_unsync;
}
-static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp);
+static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
+ int *self_deleted);
static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
{
if (sp->role.cr4_pae != !!is_pae(vcpu)) {
- kvm_mmu_zap_page(vcpu->kvm, sp);
+ kvm_mmu_zap_page(vcpu->kvm, sp, NULL);
return 1;
}
@@ -1207,7 +1208,7 @@ static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
kvm_flush_remote_tlbs(vcpu->kvm);
kvm_unlink_unsync_page(vcpu->kvm, sp);
if (vcpu->arch.mmu.sync_page(vcpu, sp)) {
- kvm_mmu_zap_page(vcpu->kvm, sp);
+ kvm_mmu_zap_page(vcpu->kvm, sp, NULL);
return 1;
}
@@ -1478,7 +1479,7 @@ static int mmu_zap_unsync_children(struct kvm *kvm,
struct kvm_mmu_page *sp;
for_each_sp(pages, sp, parents, i) {
- kvm_mmu_zap_page(kvm, sp);
+ kvm_mmu_zap_page(kvm, sp, NULL);
mmu_pages_clear_parents(&parents);
zapped++;
}
@@ -1488,7 +1489,8 @@ static int mmu_zap_unsync_children(struct kvm *kvm,
return zapped;
}
-static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
+ int *self_deleted)
{
int ret;
@@ -1505,11 +1507,16 @@ static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
if (!sp->root_count) {
hlist_del(&sp->hash_link);
kvm_mmu_free_page(kvm, sp);
+ /* Count self */
+ ret++;
+ if (self_deleted)
+ *self_deleted = 1;
} else {
sp->role.invalid = 1;
list_move(&sp->link, &kvm->arch.active_mmu_pages);
kvm_reload_remote_mmus(kvm);
}
+
kvm_mmu_reset_last_pte_updated(kvm);
return ret;
}
@@ -1538,8 +1545,7 @@ void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
page = container_of(kvm->arch.active_mmu_pages.prev,
struct kvm_mmu_page, link);
- used_pages -= kvm_mmu_zap_page(kvm, page);
- used_pages--;
+ used_pages -= kvm_mmu_zap_page(kvm, page, NULL);
}
kvm_nr_mmu_pages = used_pages;
kvm->arch.n_free_mmu_pages = 0;
@@ -1558,6 +1564,8 @@ static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
struct kvm_mmu_page *sp;
struct hlist_node *node, *n;
int r;
+ int self_deleted = 0;
+ int ret;
pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
r = 0;
@@ -1569,7 +1577,8 @@ restart:
pgprintk("%s: gfn %lx role %x\n", __func__, gfn,
sp->role.word);
r = 1;
- if (kvm_mmu_zap_page(kvm, sp))
+ ret = kvm_mmu_zap_page(kvm, sp, &self_deleted);
+ if (ret > 1 || (ret == 1 && self_deleted == 0))
goto restart;
}
return r;
@@ -1581,6 +1590,8 @@ static void mmu_unshadow(struct kvm *kvm, gfn_t gfn)
struct hlist_head *bucket;
struct kvm_mmu_page *sp;
struct hlist_node *node, *nn;
+ int ret;
+ int self_deleted = 0;
index = kvm_page_table_hashfn(gfn);
bucket = &kvm->arch.mmu_page_hash[index];
@@ -1590,7 +1601,8 @@ restart:
&& !sp->role.invalid) {
pgprintk("%s: zap %lx %x\n",
__func__, gfn, sp->role.word);
- if (kvm_mmu_zap_page(kvm, sp))
+ ret = kvm_mmu_zap_page(kvm, sp, &self_deleted);
+ if (ret > 1 || (ret == 1 && self_deleted == 0))
goto restart;
}
}
@@ -2012,7 +2024,7 @@ static void mmu_free_roots(struct kvm_vcpu *vcpu)
sp = page_header(root);
--sp->root_count;
if (!sp->root_count && sp->role.invalid)
- kvm_mmu_zap_page(vcpu->kvm, sp);
+ kvm_mmu_zap_page(vcpu->kvm, sp, NULL);
vcpu->arch.mmu.root_hpa = INVALID_PAGE;
spin_unlock(&vcpu->kvm->mmu_lock);
return;
@@ -2025,7 +2037,7 @@ static void mmu_free_roots(struct kvm_vcpu *vcpu)
sp = page_header(root);
--sp->root_count;
if (!sp->root_count && sp->role.invalid)
- kvm_mmu_zap_page(vcpu->kvm, sp);
+ kvm_mmu_zap_page(vcpu->kvm, sp, NULL);
}
vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
}
@@ -2604,6 +2616,8 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
int npte;
int r;
int invlpg_counter;
+ int ret;
+ int self_deleted = 0;
pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);
@@ -2682,7 +2696,9 @@ restart:
*/
pgprintk("misaligned: gpa %llx bytes %d role %x\n",
gpa, bytes, sp->role.word);
- if (kvm_mmu_zap_page(vcpu->kvm, sp))
+
+ ret = kvm_mmu_zap_page(vcpu->kvm, sp, &self_deleted);
+ if (ret > 1 || (ret == 1 && self_deleted == 0))
goto restart;
++vcpu->kvm->stat.mmu_flooded;
continue;
@@ -2750,7 +2766,7 @@ void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
struct kvm_mmu_page, link);
- kvm_mmu_zap_page(vcpu->kvm, sp);
+ kvm_mmu_zap_page(vcpu->kvm, sp, NULL);
++vcpu->kvm->stat.mmu_recycled;
}
}
@@ -2890,13 +2906,16 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
void kvm_mmu_zap_all(struct kvm *kvm)
{
struct kvm_mmu_page *sp, *node;
+ int ret;
+ int self_deleted = 0;
spin_lock(&kvm->mmu_lock);
restart:
- list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link)
- if (kvm_mmu_zap_page(kvm, sp))
+ list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link) {
+ ret = kvm_mmu_zap_page(kvm, sp, &self_deleted);
+ if (ret > 1 || (ret == 1 && self_deleted == 0))
goto restart;
-
+ }
spin_unlock(&kvm->mmu_lock);
kvm_flush_remote_tlbs(kvm);
@@ -2908,7 +2927,7 @@ static int kvm_mmu_remove_some_alloc_mmu_pages(struct kvm *kvm)
page = container_of(kvm->arch.active_mmu_pages.prev,
struct kvm_mmu_page, link);
- return kvm_mmu_zap_page(kvm, page) + 1;
+ return kvm_mmu_zap_page(kvm, page, NULL);
}
static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask)
--
1.6.5.2
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