[Xen-changelog] [xen-unstable] [NET] back: Allocate pages for foreign mappings individually rather than contiguously.

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID 0fe7624dde63d5a0338619fd9ba6032ae7b5cfdd
# Parent  0cda1a7988ee05359b68d09002bdd900f53a78a2
[NET] back: Allocate pages for foreign mappings individually rather than 
contiguously.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
---
 linux-2.6-xen-sparse/drivers/xen/netback/netback.c |   51 ++++++++++++---------
 1 files changed, 31 insertions(+), 20 deletions(-)

diff -r 0cda1a7988ee -r 0fe7624dde63 
linux-2.6-xen-sparse/drivers/xen/netback/netback.c
--- a/linux-2.6-xen-sparse/drivers/xen/netback/netback.c        Thu Oct 05 
22:14:39 2006 +0100
+++ b/linux-2.6-xen-sparse/drivers/xen/netback/netback.c        Thu Oct 05 
22:49:26 2006 +0100
@@ -70,8 +70,11 @@ static struct timer_list net_timer;
 
 static struct sk_buff_head rx_queue;
 
-static unsigned long mmap_vstart;
-#define MMAP_VADDR(_req) (mmap_vstart + ((_req) * PAGE_SIZE))
+static struct page **mmap_pages;
+static inline unsigned long idx_to_kaddr(unsigned int idx)
+{
+       return (unsigned long)pfn_to_kaddr(page_to_pfn(mmap_pages[idx]));
+}
 
 #define PKT_PROT_LEN 64
 
@@ -817,7 +820,7 @@ inline static void net_tx_action_dealloc
        gop = tx_unmap_ops;
        while (dc != dp) {
                pending_idx = dealloc_ring[MASK_PEND_IDX(dc++)];
-               gnttab_set_unmap_op(gop, MMAP_VADDR(pending_idx),
+               gnttab_set_unmap_op(gop, idx_to_kaddr(pending_idx),
                                    GNTMAP_host_map,
                                    grant_tx_handle[pending_idx]);
                gop++;
@@ -905,7 +908,7 @@ static gnttab_map_grant_ref_t *netbk_get
                txp = RING_GET_REQUEST(&netif->tx, cons++);
                pending_idx = pending_ring[MASK_PEND_IDX(pending_cons++)];
 
-               gnttab_set_map_op(mop++, MMAP_VADDR(pending_idx),
+               gnttab_set_map_op(mop++, idx_to_kaddr(pending_idx),
                                  GNTMAP_host_map | GNTMAP_readonly,
                                  txp->gref, netif->domid);
 
@@ -938,7 +941,7 @@ static int netbk_tx_check_mop(struct sk_
                netif_put(netif);
        } else {
                set_phys_to_machine(
-                       __pa(MMAP_VADDR(pending_idx)) >> PAGE_SHIFT,
+                       __pa(idx_to_kaddr(pending_idx)) >> PAGE_SHIFT,
                        FOREIGN_FRAME(mop->dev_bus_addr >> PAGE_SHIFT));
                grant_tx_handle[pending_idx] = mop->handle;
        }
@@ -955,7 +958,7 @@ static int netbk_tx_check_mop(struct sk_
                newerr = (++mop)->status;
                if (likely(!newerr)) {
                        set_phys_to_machine(
-                               __pa(MMAP_VADDR(pending_idx))>>PAGE_SHIFT,
+                               __pa(idx_to_kaddr(pending_idx))>>PAGE_SHIFT,
                                FOREIGN_FRAME(mop->dev_bus_addr>>PAGE_SHIFT));
                        grant_tx_handle[pending_idx] = mop->handle;
                        /* Had a previous error? Invalidate this fragment. */
@@ -1003,7 +1006,7 @@ static void netbk_fill_frags(struct sk_b
 
                pending_idx = (unsigned long)frag->page;
                txp = &pending_tx_info[pending_idx].req;
-               frag->page = virt_to_page(MMAP_VADDR(pending_idx));
+               frag->page = virt_to_page(idx_to_kaddr(pending_idx));
                frag->size = txp->size;
                frag->page_offset = txp->offset;
 
@@ -1199,7 +1202,7 @@ static void net_tx_action(unsigned long 
                        }
                }
 
-               gnttab_set_map_op(mop, MMAP_VADDR(pending_idx),
+               gnttab_set_map_op(mop, idx_to_kaddr(pending_idx),
                                  GNTMAP_host_map | GNTMAP_readonly,
                                  txreq.gref, netif->domid);
                mop++;
@@ -1258,8 +1261,8 @@ static void net_tx_action(unsigned long 
                }
 
                data_len = skb->len;
-               memcpy(skb->data, 
-                      (void *)(MMAP_VADDR(pending_idx)|txp->offset),
+               memcpy(skb->data,
+                      (void *)(idx_to_kaddr(pending_idx)|txp->offset),
                       data_len);
                if (data_len < txp->size) {
                        /* Append the packet payload as a fragment. */
@@ -1313,12 +1316,10 @@ static void netif_idx_release(u16 pendin
 
 static void netif_page_release(struct page *page)
 {
-       u16 pending_idx = page - virt_to_page(mmap_vstart);
-
        /* Ready for next use. */
        set_page_count(page, 1);
 
-       netif_idx_release(pending_idx);
+       netif_idx_release(page->index);
 }
 
 irqreturn_t netif_be_int(int irq, void *dev_id, struct pt_regs *regs)
@@ -1438,17 +1439,22 @@ static int __init netback_init(void)
        init_timer(&net_timer);
        net_timer.data = 0;
        net_timer.function = net_alarm;
-    
-       page = balloon_alloc_empty_page_range(MAX_PENDING_REQS);
-       if (page == NULL)
-               return -ENOMEM;
-
-       mmap_vstart = (unsigned long)pfn_to_kaddr(page_to_pfn(page));
+
+       mmap_pages = kmalloc(sizeof(mmap_pages[0]) * MAX_PENDING_REQS,
+                            GFP_KERNEL);
+       if (mmap_pages == NULL)
+               goto out_of_memory;
 
        for (i = 0; i < MAX_PENDING_REQS; i++) {
-               page = virt_to_page(MMAP_VADDR(i));
+               page = mmap_pages[i] = balloon_alloc_empty_page();
+               if (page == NULL) {
+                       while (--i >= 0)
+                               balloon_free_empty_page(mmap_pages[i]);
+                       goto out_of_memory;
+               }
                set_page_count(page, 1);
                SetPageForeign(page, netif_page_release);
+               page->index = i;
        }
 
        pending_cons = 0;
@@ -1472,6 +1478,11 @@ static int __init netback_init(void)
 #endif
 
        return 0;
+
+ out_of_memory:
+       kfree(mmap_pages);
+       printk("%s: out of memory\n", __FUNCTION__);
+       return -ENOMEM;
 }
 
 module_init(netback_init);

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