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-rw-r--r--tools/xenpaging/xenpaging.c42
1 files changed, 35 insertions, 7 deletions
diff --git a/tools/xenpaging/xenpaging.c b/tools/xenpaging/xenpaging.c
index 6cead5e3c7..5dff4ff5f2 100644
--- a/tools/xenpaging/xenpaging.c
+++ b/tools/xenpaging/xenpaging.c
@@ -571,6 +571,11 @@ static void put_response(struct mem_event *mem_event, mem_event_response_t *rsp)
RING_PUSH_RESPONSES(back_ring);
}
+/* Evict a given gfn
+ * Returns < 0 on fatal error
+ * Returns 0 on successful evict
+ * Returns > 0 if gfn can not be evicted
+ */
static int xenpaging_evict_page(struct xenpaging *paging, unsigned long gfn, int fd, int slot)
{
xc_interface *xch = paging->xc_handle;
@@ -580,31 +585,51 @@ static int xenpaging_evict_page(struct xenpaging *paging, unsigned long gfn, int
DECLARE_DOMCTL;
+ /* Nominate page */
+ ret = xc_mem_paging_nominate(xch, paging->mem_event.domain_id, gfn);
+ if ( ret < 0 )
+ {
+ /* unpageable gfn is indicated by EBUSY */
+ if ( errno == EBUSY )
+ ret = 1;
+ else
+ PERROR("Error nominating page %lx", gfn);
+ goto out;
+ }
+
/* Map page */
- ret = -EFAULT;
page = xc_map_foreign_pages(xch, paging->mem_event.domain_id, PROT_READ, &victim, 1);
if ( page == NULL )
{
PERROR("Error mapping page %lx", gfn);
+ ret = -1;
goto out;
}
/* Copy page */
ret = write_page(fd, page, slot);
- if ( ret != 0 )
+ if ( ret < 0 )
{
PERROR("Error copying page %lx", gfn);
munmap(page, PAGE_SIZE);
+ ret = -1;
goto out;
}
+ /* Release page */
munmap(page, PAGE_SIZE);
/* Tell Xen to evict page */
ret = xc_mem_paging_evict(xch, paging->mem_event.domain_id, gfn);
- if ( ret != 0 )
+ if ( ret < 0 )
{
- PERROR("Error evicting page %lx", gfn);
+ /* A gfn in use is indicated by EBUSY */
+ if ( errno == EBUSY )
+ {
+ ret = 1;
+ DPRINTF("Nominated page %lx busy", gfn);
+ } else
+ PERROR("Error evicting page %lx", gfn);
goto out;
}
@@ -619,6 +644,8 @@ static int xenpaging_evict_page(struct xenpaging *paging, unsigned long gfn, int
/* Record number of evicted pages */
paging->num_paged_out++;
+ ret = 0;
+
out:
return ret;
}
@@ -753,9 +780,10 @@ static int evict_victim(struct xenpaging *paging, int fd, int slot)
ret = -EINTR;
goto out;
}
- ret = xc_mem_paging_nominate(xch, paging->mem_event.domain_id, gfn);
- if ( ret == 0 )
- ret = xenpaging_evict_page(paging, gfn, fd, slot);
+
+ ret = xenpaging_evict_page(paging, gfn, fd, slot);
+ if ( ret < 0 )
+ goto out;
}
while ( ret );