diff mbox series

[v4,15/18] x86/sgx: Prepare for multiple LRUs

Message ID 20230913040635.28815-16-haitao.huang@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series Add Cgroup support for SGX EPC memory | expand

Commit Message

Haitao Huang Sept. 13, 2023, 4:06 a.m. UTC 
Add sgx_can_reclaim() wrapper and encapsulate direct references to the
global LRU list in the reclaimer functions so that they can be called with
an LRU list per EPC cgroup.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Haitao Huang <haitao.huang@linux.intel.com>
Cc: Sean Christopherson <seanjc@google.com>
---
V4:
- Re-organized this patch to include all changes related to
encapsulation of the global LRU
- Moved this patch to precede the EPC cgroup patch
---
 arch/x86/kernel/cpu/sgx/main.c | 41 +++++++++++++++++++++++-----------
 1 file changed, 28 insertions(+), 13 deletions(-)

Comments

Jarkko Sakkinen Sept. 13, 2023, 3:42 p.m. UTC | #1 
On Wed Sep 13, 2023 at 7:06 AM EEST, Haitao Huang wrote:
> Add sgx_can_reclaim() wrapper and encapsulate direct references to the
> global LRU list in the reclaimer functions so that they can be called with
> an LRU list per EPC cgroup.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
> Signed-off-by: Haitao Huang <haitao.huang@linux.intel.com>
> Cc: Sean Christopherson <seanjc@google.com>
> ---
> V4:
> - Re-organized this patch to include all changes related to
> encapsulation of the global LRU
> - Moved this patch to precede the EPC cgroup patch
> ---
>  arch/x86/kernel/cpu/sgx/main.c | 41 +++++++++++++++++++++++-----------
>  1 file changed, 28 insertions(+), 13 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index ce316bd5e5bb..3d396fe5ec09 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -34,6 +34,16 @@ static DEFINE_XARRAY(sgx_epc_address_space);
>   */
>  static struct sgx_epc_lru_lists sgx_global_lru;
>  
> +static inline struct sgx_epc_lru_lists *sgx_lru_lists(struct sgx_epc_page *epc_page)
> +{
> +	return &sgx_global_lru;
> +}

I'd simply export sgx_global_lru.

> +static inline bool sgx_can_reclaim(void)
> +{
> +	return !list_empty(&sgx_global_lru.reclaimable);
> +}


Accessors for the object should be named so that this fact is reflected,
e.g. sgx_global_lru_can_reclaim() in this case.

I would just open code this to the call sites though.

> +
>  static atomic_long_t sgx_nr_free_pages = ATOMIC_LONG_INIT(0);
>  
>  /* Nodes with one or more EPC sections. */
> @@ -339,6 +349,7 @@ size_t sgx_reclaim_epc_pages(size_t nr_to_scan, bool ignore_age)
>  	struct sgx_backing backing[SGX_NR_TO_SCAN_MAX];
>  	struct sgx_epc_page *epc_page, *tmp;
>  	struct sgx_encl_page *encl_page;
> +	struct sgx_epc_lru_lists *lru;
>  	pgoff_t page_index;
>  	LIST_HEAD(iso);
>  	size_t ret;
> @@ -372,10 +383,11 @@ size_t sgx_reclaim_epc_pages(size_t nr_to_scan, bool ignore_age)
>  		continue;
>  
>  skip:
> -		spin_lock(&sgx_global_lru.lock);
> +		lru = sgx_lru_lists(epc_page);
> +		spin_lock(&lru->lock);
>  		sgx_epc_page_set_state(epc_page, SGX_EPC_PAGE_RECLAIMABLE);
> -		list_move_tail(&epc_page->list, &sgx_global_lru.reclaimable);
> -		spin_unlock(&sgx_global_lru.lock);
> +		list_move_tail(&epc_page->list, &lru->reclaimable);
> +		spin_unlock(&lru->lock);
>  
>  		kref_put(&encl_page->encl->refcount, sgx_encl_release);
>  	}
> @@ -399,7 +411,7 @@ size_t sgx_reclaim_epc_pages(size_t nr_to_scan, bool ignore_age)
>  static bool sgx_should_reclaim(unsigned long watermark)
>  {
>  	return atomic_long_read(&sgx_nr_free_pages) < watermark &&
> -	       !list_empty(&sgx_global_lru.reclaimable);
> +		sgx_can_reclaim();
>  }
>  
>  /*
> @@ -529,14 +541,16 @@ struct sgx_epc_page *__sgx_alloc_epc_page(void)
>   */
>  void sgx_record_epc_page(struct sgx_epc_page *page, unsigned long flags)
>  {
> -	spin_lock(&sgx_global_lru.lock);
> +	struct sgx_epc_lru_lists *lru = sgx_lru_lists(page);
> +
> +	spin_lock(&lru->lock);
>  	WARN_ON_ONCE(sgx_epc_page_reclaimable(page->flags));
>  	page->flags |= flags;
>  	if (sgx_epc_page_reclaimable(flags))
> -		list_add_tail(&page->list, &sgx_global_lru.reclaimable);
> +		list_add_tail(&page->list, &lru->reclaimable);
>  	else
> -		list_add_tail(&page->list, &sgx_global_lru.unreclaimable);
> -	spin_unlock(&sgx_global_lru.lock);
> +		list_add_tail(&page->list, &lru->unreclaimable);
> +	spin_unlock(&lru->lock);
>  }
>  
>  /**
> @@ -551,15 +565,16 @@ void sgx_record_epc_page(struct sgx_epc_page *page, unsigned long flags)
>   */
>  int sgx_drop_epc_page(struct sgx_epc_page *page)
>  {
> -	spin_lock(&sgx_global_lru.lock);
> +	struct sgx_epc_lru_lists *lru = sgx_lru_lists(page);
> +
> +	spin_lock(&lru->lock);
>  	if (sgx_epc_page_reclaim_in_progress(page->flags)) {
> -		spin_unlock(&sgx_global_lru.lock);
> +		spin_unlock(&lru->lock);
>  		return -EBUSY;
>  	}
> -
>  	list_del(&page->list);
>  	sgx_epc_page_reset_state(page);
> -	spin_unlock(&sgx_global_lru.lock);
> +	spin_unlock(&lru->lock);
>  
>  	return 0;
>  }
> @@ -592,7 +607,7 @@ struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim)
>  			break;
>  		}
>  
> -		if (list_empty(&sgx_global_lru.reclaimable))
> +		if (!sgx_can_reclaim())
>  			return ERR_PTR(-ENOMEM);
>  
>  		if (!reclaim) {
> -- 
> 2.25.1

BR, Jarkko
Haitao Huang Sept. 16, 2023, 4:18 a.m. UTC | #2 
On Wed, 13 Sep 2023 10:42:52 -0500, Jarkko Sakkinen <jarkko@kernel.org>  
wrote:

> On Wed Sep 13, 2023 at 7:06 AM EEST, Haitao Huang wrote:
>> Add sgx_can_reclaim() wrapper and encapsulate direct references to the
>> global LRU list in the reclaimer functions so that they can be called  
>> with
>> an LRU list per EPC cgroup.
>>
>> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
>> Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
>> Signed-off-by: Haitao Huang <haitao.huang@linux.intel.com>
>> Cc: Sean Christopherson <seanjc@google.com>
>> ---
>> V4:
>> - Re-organized this patch to include all changes related to
>> encapsulation of the global LRU
>> - Moved this patch to precede the EPC cgroup patch
>> ---
>>  arch/x86/kernel/cpu/sgx/main.c | 41 +++++++++++++++++++++++-----------
>>  1 file changed, 28 insertions(+), 13 deletions(-)
>>
>> diff --git a/arch/x86/kernel/cpu/sgx/main.c  
>> b/arch/x86/kernel/cpu/sgx/main.c
>> index ce316bd5e5bb..3d396fe5ec09 100644
>> --- a/arch/x86/kernel/cpu/sgx/main.c
>> +++ b/arch/x86/kernel/cpu/sgx/main.c
>> @@ -34,6 +34,16 @@ static DEFINE_XARRAY(sgx_epc_address_space);
>>   */
>>  static struct sgx_epc_lru_lists sgx_global_lru;
>>
>> +static inline struct sgx_epc_lru_lists *sgx_lru_lists(struct  
>> sgx_epc_page *epc_page)
>> +{
>> +	return &sgx_global_lru;
>> +}
>
> I'd simply export sgx_global_lru.
>
The purpose of this patch to to hide sgx_global_lru so later we can have  
LRU per cgroup.
I'll update the commit message to make it clear this is not just for   
sgx_can_reclaim

>> +static inline bool sgx_can_reclaim(void)
>> +{
>> +	return !list_empty(&sgx_global_lru.reclaimable);
>> +}
>
>
> Accessors for the object should be named so that this fact is reflected,
> e.g. sgx_global_lru_can_reclaim() in this case.
>
> I would just open code this to the call sites though.
>
ditto

Thanks
Haitao
diff mbox series

Patch

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index ce316bd5e5bb..3d396fe5ec09 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -34,6 +34,16 @@  static DEFINE_XARRAY(sgx_epc_address_space);
  */
 static struct sgx_epc_lru_lists sgx_global_lru;
 
+static inline struct sgx_epc_lru_lists *sgx_lru_lists(struct sgx_epc_page *epc_page)
+{
+	return &sgx_global_lru;
+}
+
+static inline bool sgx_can_reclaim(void)
+{
+	return !list_empty(&sgx_global_lru.reclaimable);
+}
+
 static atomic_long_t sgx_nr_free_pages = ATOMIC_LONG_INIT(0);
 
 /* Nodes with one or more EPC sections. */
@@ -339,6 +349,7 @@  size_t sgx_reclaim_epc_pages(size_t nr_to_scan, bool ignore_age)
 	struct sgx_backing backing[SGX_NR_TO_SCAN_MAX];
 	struct sgx_epc_page *epc_page, *tmp;
 	struct sgx_encl_page *encl_page;
+	struct sgx_epc_lru_lists *lru;
 	pgoff_t page_index;
 	LIST_HEAD(iso);
 	size_t ret;
@@ -372,10 +383,11 @@  size_t sgx_reclaim_epc_pages(size_t nr_to_scan, bool ignore_age)
 		continue;
 
 skip:
-		spin_lock(&sgx_global_lru.lock);
+		lru = sgx_lru_lists(epc_page);
+		spin_lock(&lru->lock);
 		sgx_epc_page_set_state(epc_page, SGX_EPC_PAGE_RECLAIMABLE);
-		list_move_tail(&epc_page->list, &sgx_global_lru.reclaimable);
-		spin_unlock(&sgx_global_lru.lock);
+		list_move_tail(&epc_page->list, &lru->reclaimable);
+		spin_unlock(&lru->lock);
 
 		kref_put(&encl_page->encl->refcount, sgx_encl_release);
 	}
@@ -399,7 +411,7 @@  size_t sgx_reclaim_epc_pages(size_t nr_to_scan, bool ignore_age)
 static bool sgx_should_reclaim(unsigned long watermark)
 {
 	return atomic_long_read(&sgx_nr_free_pages) < watermark &&
-	       !list_empty(&sgx_global_lru.reclaimable);
+		sgx_can_reclaim();
 }
 
 /*
@@ -529,14 +541,16 @@  struct sgx_epc_page *__sgx_alloc_epc_page(void)
  */
 void sgx_record_epc_page(struct sgx_epc_page *page, unsigned long flags)
 {
-	spin_lock(&sgx_global_lru.lock);
+	struct sgx_epc_lru_lists *lru = sgx_lru_lists(page);
+
+	spin_lock(&lru->lock);
 	WARN_ON_ONCE(sgx_epc_page_reclaimable(page->flags));
 	page->flags |= flags;
 	if (sgx_epc_page_reclaimable(flags))
-		list_add_tail(&page->list, &sgx_global_lru.reclaimable);
+		list_add_tail(&page->list, &lru->reclaimable);
 	else
-		list_add_tail(&page->list, &sgx_global_lru.unreclaimable);
-	spin_unlock(&sgx_global_lru.lock);
+		list_add_tail(&page->list, &lru->unreclaimable);
+	spin_unlock(&lru->lock);
 }
 
 /**
@@ -551,15 +565,16 @@  void sgx_record_epc_page(struct sgx_epc_page *page, unsigned long flags)
  */
 int sgx_drop_epc_page(struct sgx_epc_page *page)
 {
-	spin_lock(&sgx_global_lru.lock);
+	struct sgx_epc_lru_lists *lru = sgx_lru_lists(page);
+
+	spin_lock(&lru->lock);
 	if (sgx_epc_page_reclaim_in_progress(page->flags)) {
-		spin_unlock(&sgx_global_lru.lock);
+		spin_unlock(&lru->lock);
 		return -EBUSY;
 	}
-
 	list_del(&page->list);
 	sgx_epc_page_reset_state(page);
-	spin_unlock(&sgx_global_lru.lock);
+	spin_unlock(&lru->lock);
 
 	return 0;
 }
@@ -592,7 +607,7 @@  struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim)
 			break;
 		}
 
-		if (list_empty(&sgx_global_lru.reclaimable))
+		if (!sgx_can_reclaim())
 			return ERR_PTR(-ENOMEM);
 
 		if (!reclaim) {