diff mbox

[11/16] netvm: Propagate page->pfmemalloc from skb_alloc_page to skb

Message ID 1340375443-22455-12-git-send-email-mgorman@suse.de
State Not Applicable, archived
Delegated to: David Miller
Headers show

Commit Message

Mel Gorman June 22, 2012, 2:30 p.m. UTC 
The skb->pfmemalloc flag gets set to true iff during the slab
allocation of data in __alloc_skb that the the PFMEMALLOC reserves
were used. If page splitting is used, it is possible that pages will
be allocated from the PFMEMALLOC reserve without propagating this
information to the skb. This patch propagates page->pfmemalloc from
pages allocated for fragments to the skb.

It works by reintroducing and expanding the skb_alloc_page() API
to take an skb. If the page was allocated from pfmemalloc reserves,
it is automatically copied. If the driver allocates the page before
the skb, it should call skb_propagate_pfmemalloc() after the skb is
allocated to ensure the flag is copied properly.

Failure to do so is not critical. The resulting driver may perform
slower if it is used for swap-over-NBD or swap-over-NFS but it should
not result in failure.

[davem@davemloft.net: API rename and consistency]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/ethernet/chelsio/cxgb4/sge.c          |    2 +-
 drivers/net/ethernet/chelsio/cxgb4vf/sge.c        |    2 +-
 drivers/net/ethernet/intel/igb/igb_main.c         |    2 +-
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c     |    4 +-
 drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |    3 +-
 drivers/net/usb/cdc-phonet.c                      |    2 +-
 drivers/usb/gadget/f_phonet.c                     |    2 +-
 include/linux/skbuff.h                            |   55 +++++++++++++++++++++
 8 files changed, 64 insertions(+), 8 deletions(-)

Comments

Sebastian Andrzej Siewior June 26, 2012, 8:13 p.m. UTC | #1 
On Fri, Jun 22, 2012 at 03:30:38PM +0100, Mel Gorman wrote:
>  drivers/net/ethernet/chelsio/cxgb4/sge.c          |    2 +-
>  drivers/net/ethernet/chelsio/cxgb4vf/sge.c        |    2 +-
>  drivers/net/ethernet/intel/igb/igb_main.c         |    2 +-
>  drivers/net/ethernet/intel/ixgbe/ixgbe_main.c     |    4 +-
>  drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |    3 +-
>  drivers/net/usb/cdc-phonet.c                      |    2 +-
>  drivers/usb/gadget/f_phonet.c                     |    2 +-

You did not touch all drivers which use alloc_page(s)() like e1000(e). Was
this on purpose?

Sebastian
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Mel Gorman June 27, 2012, 8:43 a.m. UTC | #2 
On Tue, Jun 26, 2012 at 10:13:28PM +0200, Sebastian Andrzej Siewior wrote:
> On Fri, Jun 22, 2012 at 03:30:38PM +0100, Mel Gorman wrote:
> >  drivers/net/ethernet/chelsio/cxgb4/sge.c          |    2 +-
> >  drivers/net/ethernet/chelsio/cxgb4vf/sge.c        |    2 +-
> >  drivers/net/ethernet/intel/igb/igb_main.c         |    2 +-
> >  drivers/net/ethernet/intel/ixgbe/ixgbe_main.c     |    4 +-
> >  drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |    3 +-
> >  drivers/net/usb/cdc-phonet.c                      |    2 +-
> >  drivers/usb/gadget/f_phonet.c                     |    2 +-
> 
> You did not touch all drivers which use alloc_page(s)() like e1000(e). Was
> this on purpose?
> 

Yes. The ones I changed were the semi-obvious ones and carried over from
when the patches were completely out of tree.  As the changelog notes
it is not critical that these annotation happens and can be fixed on a
per-driver basis if there are complains about network swapping being slow.

In the e1000 case, alloc_page is called from e1000_alloc_jumbo_rx_buffers
and I would not have paid quite as close attention to jumbo configurations
even though e1000 does not depend on high-order allocations like some
other drivers do. I can update e1000 if you like but it's not critical
to do so and in fact getting a bug reporting saying that network swap
was slow on e1000 would be useful to me in its own way :)
Sebastian Andrzej Siewior July 9, 2012, 7:18 p.m. UTC | #3 
On Wed, Jun 27, 2012 at 09:43:48AM +0100, Mel Gorman wrote:
> > You did not touch all drivers which use alloc_page(s)() like e1000(e). Was
> > this on purpose?
> 
> Yes. The ones I changed were the semi-obvious ones and carried over from
> when the patches were completely out of tree.  As the changelog notes
> it is not critical that these annotation happens and can be fixed on a
> per-driver basis if there are complains about network swapping being slow.
okay, I was just curious why some drivers were updated and others not.

> I can update e1000 if you like but it's not critical
> to do so and in fact getting a bug reporting saying that network swap
> was slow on e1000 would be useful to me in its own way :)
No, leave as it, I was just curious.
One thing: Do you think it makes sense to you introduce
	#define GFP_NET_RX     (GFP_ATOMIC | __GFP_MEMALLOC)

and use it within the receive path instead of GFP_ATOMIC?

Sebastian
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Mel Gorman July 10, 2012, 11:12 a.m. UTC | #4 
On Mon, Jul 09, 2012 at 09:18:56PM +0200, Sebastian Andrzej Siewior wrote:
> 
> > I can update e1000 if you like but it's not critical
> > to do so and in fact getting a bug reporting saying that network swap
> > was slow on e1000 would be useful to me in its own way :)
> No, leave as it, I was just curious.
> One thing: Do you think it makes sense to you introduce
> 	#define GFP_NET_RX     (GFP_ATOMIC | __GFP_MEMALLOC)
> 
> and use it within the receive path instead of GFP_ATOMIC?
> 

For now, I'd prefer to keep the __GFP_MEMALLOC flag at the different
callsites because it forces people to think about what it means.  I fear
that GFP_NET_RX may be too easy to misuse without thinking about what the
consequences are.
diff mbox

Patch

diff --git a/drivers/net/ethernet/chelsio/cxgb4/sge.c b/drivers/net/ethernet/chelsio/cxgb4/sge.c
index 8596aca..d49933e 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/sge.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/sge.c
@@ -528,7 +528,7 @@  static unsigned int refill_fl(struct adapter *adap, struct sge_fl *q, int n,
 #endif
 
 	while (n--) {
-		pg = alloc_page(gfp);
+		pg = __skb_alloc_page(gfp, NULL);
 		if (unlikely(!pg)) {
 			q->alloc_failed++;
 			break;
diff --git a/drivers/net/ethernet/chelsio/cxgb4vf/sge.c b/drivers/net/ethernet/chelsio/cxgb4vf/sge.c
index f2d1ecd..8877fbf 100644
--- a/drivers/net/ethernet/chelsio/cxgb4vf/sge.c
+++ b/drivers/net/ethernet/chelsio/cxgb4vf/sge.c
@@ -653,7 +653,7 @@  static unsigned int refill_fl(struct adapter *adapter, struct sge_fl *fl,
 
 alloc_small_pages:
 	while (n--) {
-		page = alloc_page(gfp | __GFP_NOWARN | __GFP_COLD);
+		page = __skb_alloc_page(gfp | __GFP_NOWARN, NULL);
 		if (unlikely(!page)) {
 			fl->alloc_failed++;
 			break;
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 01ced68..16e0892 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -6233,7 +6233,7 @@  static bool igb_alloc_mapped_page(struct igb_ring *rx_ring,
 		return true;
 
 	if (!page) {
-		page = alloc_page(GFP_ATOMIC | __GFP_COLD);
+		page = __skb_alloc_page(GFP_ATOMIC, bi->skb);
 		bi->page = page;
 		if (unlikely(!page)) {
 			rx_ring->rx_stats.alloc_failed++;
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 21e083c..94f586b 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -1146,8 +1146,8 @@  static bool ixgbe_alloc_mapped_page(struct ixgbe_ring *rx_ring,
 
 	/* alloc new page for storage */
 	if (likely(!page)) {
-		page = alloc_pages(GFP_ATOMIC | __GFP_COLD | __GFP_COMP,
-				   ixgbe_rx_pg_order(rx_ring));
+		page = __skb_alloc_pages(GFP_ATOMIC | __GFP_COLD | __GFP_COMP,
+				 	 bi->skb, ixgbe_rx_pg_order(rx_ring));
 		if (unlikely(!page)) {
 			rx_ring->rx_stats.alloc_rx_page_failed++;
 			return false;
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index f69ec42..cd65fd8 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -369,7 +369,7 @@  static void ixgbevf_alloc_rx_buffers(struct ixgbevf_adapter *adapter,
 		if (!bi->page_dma &&
 		    (adapter->flags & IXGBE_FLAG_RX_PS_ENABLED)) {
 			if (!bi->page) {
-				bi->page = alloc_page(GFP_ATOMIC | __GFP_COLD);
+				bi->page = __skb_alloc_page(GFP_ATOMIC, NULL);
 				if (!bi->page) {
 					adapter->alloc_rx_page_failed++;
 					goto no_buffers;
@@ -403,6 +403,7 @@  static void ixgbevf_alloc_rx_buffers(struct ixgbevf_adapter *adapter,
 			 */
 			skb_reserve(skb, NET_IP_ALIGN);
 
+			skb_propagate_pfmemalloc(bi->page, skb);
 			bi->skb = skb;
 		}
 		if (!bi->dma) {
diff --git a/drivers/net/usb/cdc-phonet.c b/drivers/net/usb/cdc-phonet.c
index 187c144..6461004 100644
--- a/drivers/net/usb/cdc-phonet.c
+++ b/drivers/net/usb/cdc-phonet.c
@@ -130,7 +130,7 @@  static int rx_submit(struct usbpn_dev *pnd, struct urb *req, gfp_t gfp_flags)
 	struct page *page;
 	int err;
 
-	page = alloc_page(gfp_flags);
+	page = __skb_alloc_page(gfp_flags | __GFP_NOMEMALLOC, NULL);
 	if (!page)
 		return -ENOMEM;
 
diff --git a/drivers/usb/gadget/f_phonet.c b/drivers/usb/gadget/f_phonet.c
index 965a629..8ee9268 100644
--- a/drivers/usb/gadget/f_phonet.c
+++ b/drivers/usb/gadget/f_phonet.c
@@ -301,7 +301,7 @@  pn_rx_submit(struct f_phonet *fp, struct usb_request *req, gfp_t gfp_flags)
 	struct page *page;
 	int err;
 
-	page = alloc_page(gfp_flags);
+	page = __skb_alloc_page(gfp_flags | __GFP_NOMEMALLOC, NULL);
 	if (!page)
 		return -ENOMEM;
 
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index b814bb8..7632c87 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1774,6 +1774,61 @@  static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
 	return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
 }
 
+/*
+ *	__skb_alloc_page - allocate pages for ps-rx on a skb and preserve pfmemalloc data
+ *	@gfp_mask: alloc_pages_node mask. Set __GFP_NOMEMALLOC if not for network packet RX
+ *	@skb: skb to set pfmemalloc on if __GFP_MEMALLOC is used
+ *	@order: size of the allocation
+ *
+ * 	Allocate a new page.
+ *
+ * 	%NULL is returned if there is no free memory.
+*/
+static inline struct page *__skb_alloc_pages(gfp_t gfp_mask,
+					      struct sk_buff *skb,
+					      unsigned int order)
+{
+	struct page *page;
+
+	gfp_mask |= __GFP_COLD;
+
+	if (!(gfp_mask & __GFP_NOMEMALLOC))
+		gfp_mask |= __GFP_MEMALLOC;
+
+	page = alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
+	if (skb && page && page->pfmemalloc)
+		skb->pfmemalloc = true;
+
+	return page;
+}
+
+/**
+ *	__skb_alloc_page - allocate a page for ps-rx for a given skb and preserve pfmemalloc data
+ *	@gfp_mask: alloc_pages_node mask. Set __GFP_NOMEMALLOC if not for network packet RX
+ *	@skb: skb to set pfmemalloc on if __GFP_MEMALLOC is used
+ *
+ * 	Allocate a new page.
+ *
+ * 	%NULL is returned if there is no free memory.
+ */
+static inline struct page *__skb_alloc_page(gfp_t gfp_mask,
+					     struct sk_buff *skb)
+{
+	return __skb_alloc_pages(gfp_mask, skb, 0);
+}
+
+/**
+ *	skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
+ *	@page: The page that was allocated from skb_alloc_page
+ *	@skb: The skb that may need pfmemalloc set
+ */
+static inline void skb_propagate_pfmemalloc(struct page *page,
+					     struct sk_buff *skb)
+{
+	if (page && page->pfmemalloc)
+		skb->pfmemalloc = true;
+}
+
 /**
  * skb_frag_page - retrieve the page refered to by a paged fragment
  * @frag: the paged fragment