[Xen-devel] [PATCH 01/12] xenpaging: remove domain_id and mfn from struct xenpaging_victim

[Olaf Hering <olaf@xxxxxxxxx>]

Remove unused member 'mfn' from struct xenpaging_victim.

xenpaging operates on a single guest, so it needs only a single domain_id.
Remove domain_id from struct xenpaging_victim and use the one from
paging->mem_event where needed. Its not used in the policy.

This saves 4MB runtime data with a 1GB pagefile.

Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>

---
 tools/xenpaging/policy.h         |    7 +++----
 tools/xenpaging/policy_default.c |   10 +++-------
 tools/xenpaging/xenpaging.c      |   26 ++++++++++++--------------
 tools/xenpaging/xenpaging.h      |    4 ----
 4 files changed, 18 insertions(+), 29 deletions(-)

--- xen-unstable.hg-4.1.22694.orig/tools/xenpaging/policy.h
+++ xen-unstable.hg-4.1.22694/tools/xenpaging/policy.h
@@ -29,10 +29,9 @@
 
 
 int policy_init(xenpaging_t *paging);
-int policy_choose_victim(xenpaging_t *paging, domid_t domain_id,
-                         xenpaging_victim_t *victim);
-void policy_notify_paged_out(domid_t domain_id, unsigned long gfn);
-void policy_notify_paged_in(domid_t domain_id, unsigned long gfn);
+int policy_choose_victim(xenpaging_t *paging, xenpaging_victim_t *victim);
+void policy_notify_paged_out(unsigned long gfn);
+void policy_notify_paged_in(unsigned long gfn);
 
 #endif // __XEN_PAGING_POLICY_H__
 
--- xen-unstable.hg-4.1.22694.orig/tools/xenpaging/policy_default.c
+++ xen-unstable.hg-4.1.22694/tools/xenpaging/policy_default.c
@@ -67,16 +67,12 @@ int policy_init(xenpaging_t *paging)
     return rc;
 }
 
-int policy_choose_victim(xenpaging_t *paging, domid_t domain_id,
-                         xenpaging_victim_t *victim)
+int policy_choose_victim(xenpaging_t *paging, xenpaging_victim_t *victim)
 {
     xc_interface *xch = paging->xc_handle;
     unsigned long wrap = current_gfn;
     ASSERT(victim != NULL);
 
-    /* Domain to pick on */
-    victim->domain_id = domain_id;
-
     do
     {
         current_gfn++;
@@ -96,13 +92,13 @@ int policy_choose_victim(xenpaging_t *pa
     return 0;
 }
 
-void policy_notify_paged_out(domid_t domain_id, unsigned long gfn)
+void policy_notify_paged_out(unsigned long gfn)
 {
     set_bit(gfn, bitmap);
     clear_bit(gfn, unconsumed);
 }
 
-void policy_notify_paged_in(domid_t domain_id, unsigned long gfn)
+void policy_notify_paged_in(unsigned long gfn)
 {
     unsigned long old_gfn = mru[i_mru & (MRU_SIZE - 1)];
 
--- xen-unstable.hg-4.1.22694.orig/tools/xenpaging/xenpaging.c
+++ xen-unstable.hg-4.1.22694/tools/xenpaging/xenpaging.c
@@ -171,7 +171,7 @@ xenpaging_t *xenpaging_init(domid_t doma
         goto err;
     }
 
-    rc = xc_get_platform_info(xch, domain_id,
+    rc = xc_get_platform_info(xch, paging->mem_event.domain_id,
                               paging->platform_info);
     if ( rc != 1 )
     {
@@ -187,7 +187,7 @@ xenpaging_t *xenpaging_init(domid_t doma
         goto err;
     }
 
-    rc = xc_domain_getinfolist(xch, domain_id, 1,
+    rc = xc_domain_getinfolist(xch, paging->mem_event.domain_id, 1,
                                paging->domain_info);
     if ( rc != 1 )
     {
@@ -348,7 +348,7 @@ int xenpaging_evict_page(xenpaging_t *pa
     /* Map page */
     gfn = victim->gfn;
     ret = -EFAULT;
-    page = xc_map_foreign_pages(xch, victim->domain_id,
+    page = xc_map_foreign_pages(xch, paging->mem_event.domain_id,
                                 PROT_READ | PROT_WRITE, &gfn, 1);
     if ( page == NULL )
     {
@@ -380,7 +380,7 @@ int xenpaging_evict_page(xenpaging_t *pa
     }
 
     /* Notify policy of page being paged out */
-    policy_notify_paged_out(paging->mem_event.domain_id, victim->gfn);
+    policy_notify_paged_out(victim->gfn);
 
  out:
     return ret;
@@ -397,7 +397,7 @@ static int xenpaging_resume_page(xenpagi
 
     /* Notify policy of page being paged in */
     if ( notify_policy )
-        policy_notify_paged_in(paging->mem_event.domain_id, rsp->gfn);
+        policy_notify_paged_in(rsp->gfn);
 
     /* Tell Xen page is ready */
     ret = xc_mem_paging_resume(paging->xc_handle, paging->mem_event.domain_id,
@@ -464,7 +464,7 @@ static int xenpaging_populate_page(xenpa
     return ret;
 }
 
-static int evict_victim(xenpaging_t *paging, domid_t domain_id,
+static int evict_victim(xenpaging_t *paging,
                         xenpaging_victim_t *victim, int fd, int i)
 {
     xc_interface *xch = paging->xc_handle;
@@ -473,7 +473,7 @@ static int evict_victim(xenpaging_t *pag
 
     do
     {
-        ret = policy_choose_victim(paging, domain_id, victim);
+        ret = policy_choose_victim(paging, victim);
         if ( ret != 0 )
         {
             if ( ret != -ENOSPC )
@@ -486,14 +486,13 @@ static int evict_victim(xenpaging_t *pag
             ret = -EINTR;
             goto out;
         }
-        ret = xc_mem_paging_nominate(xch,
-                                     paging->mem_event.domain_id, victim->gfn);
+        ret = xc_mem_paging_nominate(xch, paging->mem_event.domain_id, 
victim->gfn);
         if ( ret == 0 )
             ret = xenpaging_evict_page(paging, victim, fd, i);
         else
         {
             if ( j++ % 1000 == 0 )
-                if ( xc_mem_paging_flush_ioemu_cache(domain_id) )
+                if ( 
xc_mem_paging_flush_ioemu_cache(paging->mem_event.domain_id) )
                     ERROR("Error flushing ioemu cache");
         }
     }
@@ -578,7 +577,7 @@ int main(int argc, char *argv[])
     memset(victims, 0, sizeof(xenpaging_victim_t) * num_pages);
     for ( i = 0; i < num_pages; i++ )
     {
-        rc = evict_victim(paging, domain_id, &victims[i], fd, i);
+        rc = evict_victim(paging, &victims[i], fd, i);
         if ( rc == -ENOSPC )
             break;
         if ( rc == -EINTR )
@@ -619,8 +618,7 @@ int main(int argc, char *argv[])
                 /* Find where in the paging file to read from */
                 for ( i = 0; i < num_pages; i++ )
                 {
-                    if ( (victims[i].domain_id == paging->mem_event.domain_id) 
&&
-                         (victims[i].gfn == req.gfn) )
+                    if ( victims[i].gfn == req.gfn )
                         break;
                 }
     
@@ -652,7 +650,7 @@ int main(int argc, char *argv[])
                 }
 
                 /* Evict a new page to replace the one we just paged in */
-                evict_victim(paging, domain_id, &victims[i], fd, i);
+                evict_victim(paging, &victims[i], fd, i);
             }
             else
             {
--- xen-unstable.hg-4.1.22694.orig/tools/xenpaging/xenpaging.h
+++ xen-unstable.hg-4.1.22694/tools/xenpaging/xenpaging.h
@@ -49,12 +49,8 @@ typedef struct xenpaging {
 
 
 typedef struct xenpaging_victim {
-    /* the domain to evict a page from */
-    domid_t domain_id;
     /* the gfn of the page to evict */
     unsigned long gfn;
-    /* the mfn of evicted page */
-    unsigned long mfn;
 } xenpaging_victim_t;
 
 


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