[PATCH 00 of 12] xenpaging fixes for xen-unstable

[PATCH 00 of 12] xenpaging fixes for xen-unstable

[Olaf Hering]

The following series of changes for xenpaging fixes a few bugs, does some
cleanup and adds two new features to the pager.
It is now possible to run the pager manually and stop it with ctrl-c, without
corrupting the guest. A shutdown of a guest is also catched with a xenstore
watch.

Please review and apply.

Olaf

 tools/xenpaging/Makefile         |    2 
 tools/xenpaging/pagein.c         |   68 +++++++++++++++++++
 tools/xenpaging/policy_default.c |    4 +
 tools/xenpaging/watch.c          |   79 ++++++++++++++++++++++
 tools/xenpaging/xenpaging.c      |  138 ++++++++++++++++++++++-----------------
 tools/xenpaging/xenpaging.h      |    5 +
 xen/arch/x86/mm/p2m.c            |    1 
 7 files changed, 238 insertions(+), 59 deletions(-)

[PATCH 01 of 12] xenpaging: correct dropping of pages to avoid full ring buffer

[Olaf Hering]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1307437209 -7200
# Node ID 6b8446bf4e5fbfa93169ec2509364c0fde74beca
# Parent  c231a26a29327aa3c737170e04c738289be2d309
xenpaging: correct dropping of pages to avoid full ring buffer

Doing a one-way channel from Xen to xenpaging is not possible with the
current ring buffer implementation. xenpaging uses the mem_event ring
buffer, which expects request/response pairs to make progress. The
previous patch, which tried to establish a one-way communication from
Xen to xenpaging, stalled the guest once the buffer was filled up with
requests. Correct page-dropping by taking the slow path and let
p2m_mem_paging_resume() consume the response from xenpaging. This makes
room for yet another request/response pair and avoids hanging guests.

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r c231a26a2932 -r 6b8446bf4e5f tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c	Mon Jun 06 09:56:08 2011 +0100
+++ b/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:09 2011 +0200
@@ -653,19 +653,19 @@ int main(int argc, char *argv[])
                         ERROR("Error populating page");
                         goto out;
                     }
+                }
 
-                    /* Prepare the response */
-                    rsp.gfn = req.gfn;
-                    rsp.p2mt = req.p2mt;
-                    rsp.vcpu_id = req.vcpu_id;
-                    rsp.flags = req.flags;
+                /* Prepare the response */
+                rsp.gfn = req.gfn;
+                rsp.p2mt = req.p2mt;
+                rsp.vcpu_id = req.vcpu_id;
+                rsp.flags = req.flags;
 
-                    rc = xenpaging_resume_page(paging, &rsp, 1);
-                    if ( rc != 0 )
-                    {
-                        ERROR("Error resuming page");
-                        goto out;
-                    }
+                rc = xenpaging_resume_page(paging, &rsp, 1);
+                if ( rc != 0 )
+                {
+                    ERROR("Error resuming page");
+                    goto out;
                 }
 
                 /* Evict a new page to replace the one we just paged in */

[PATCH 02 of 12] xenpaging: do not bounce p2mt to xenpaging

[Olaf Hering]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1307437210 -7200
# Node ID d22489c1b10a7fd17fca635d0a29dc774cf97bf3
# Parent  6b8446bf4e5fbfa93169ec2509364c0fde74beca
xenpaging: do not bounce p2mt to xenpaging

do not bounce p2mt to xenpaging because p2m_mem_paging_populate() and
p2m_mem_paging_resume() dont make use of p2mt

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r 6b8446bf4e5f -r d22489c1b10a tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:09 2011 +0200
+++ b/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:10 2011 +0200
@@ -657,7 +657,6 @@ int main(int argc, char *argv[])
 
                 /* Prepare the response */
                 rsp.gfn = req.gfn;
-                rsp.p2mt = req.p2mt;
                 rsp.vcpu_id = req.vcpu_id;
                 rsp.flags = req.flags;
 
@@ -674,10 +673,8 @@ int main(int argc, char *argv[])
             else
             {
                 DPRINTF("page already populated (domain = %d; vcpu = %d;"
-                        " p2mt = %x;"
                         " gfn = %"PRIx64"; paused = %d)\n",
                         paging->mem_event.domain_id, req.vcpu_id,
-                        req.p2mt,
                         req.gfn, req.flags & MEM_EVENT_FLAG_VCPU_PAUSED);
 
                 /* Tell Xen to resume the vcpu */
@@ -686,7 +683,6 @@ int main(int argc, char *argv[])
                 {
                     /* Prepare the response */
                     rsp.gfn = req.gfn;
-                    rsp.p2mt = req.p2mt;
                     rsp.vcpu_id = req.vcpu_id;
                     rsp.flags = req.flags;
 
diff -r 6b8446bf4e5f -r d22489c1b10a xen/arch/x86/mm/p2m.c
--- a/xen/arch/x86/mm/p2m.c	Tue Jun 07 11:00:09 2011 +0200
+++ b/xen/arch/x86/mm/p2m.c	Tue Jun 07 11:00:10 2011 +0200
@@ -773,7 +773,6 @@ void p2m_mem_paging_populate(struct doma
 
     /* Send request to pager */
     req.gfn = gfn;
-    req.p2mt = p2mt;
     req.vcpu_id = v->vcpu_id;
 
     mem_event_put_request(d, &req);

[PATCH 03 of 12] xenpaging: remove srand call

[Olaf Hering]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1307437211 -7200
# Node ID e2480aad3a3bd4e801bd79daf1b6ee77efe1ed7c
# Parent  d22489c1b10a7fd17fca635d0a29dc774cf97bf3
xenpaging: remove srand call

The policy uses now a linear algorithm instead of a random one.
Remove the call to srand().

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r d22489c1b10a -r e2480aad3a3b tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:10 2011 +0200
+++ b/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:11 2011 +0200
@@ -544,9 +544,6 @@ int main(int argc, char *argv[])
     domain_id = atoi(argv[1]);
     num_pages = atoi(argv[2]);
 
-    /* Seed random-number generator */
-    srand(time(NULL));
-
     /* Initialise domain paging */
     paging = xenpaging_init(domain_id);
     if ( paging == NULL )

[PATCH 04 of 12] xenpaging: remove return values from functions that can not fail

[Olaf Hering]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1307437212 -7200
# Node ID c31636354b69164c06e86feed58f9713656b8f0c
# Parent  e2480aad3a3bd4e801bd79daf1b6ee77efe1ed7c
xenpaging: remove return values from functions that can not fail

get_request() and put_response() can not fail, remove return value
and update calling functions.

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r e2480aad3a3b -r c31636354b69 tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:11 2011 +0200
+++ b/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:12 2011 +0200
@@ -297,7 +297,7 @@ static int xenpaging_teardown(xenpaging_
     return -1;
 }
 
-static int get_request(mem_event_t *mem_event, mem_event_request_t *req)
+static void get_request(mem_event_t *mem_event, mem_event_request_t *req)
 {
     mem_event_back_ring_t *back_ring;
     RING_IDX req_cons;
@@ -316,11 +316,9 @@ static int get_request(mem_event_t *mem_
     back_ring->sring->req_event = req_cons + 1;
 
     mem_event_ring_unlock(mem_event);
-
-    return 0;
 }
 
-static int put_response(mem_event_t *mem_event, mem_event_response_t *rsp)
+static void put_response(mem_event_t *mem_event, mem_event_response_t *rsp)
 {
     mem_event_back_ring_t *back_ring;
     RING_IDX rsp_prod;
@@ -339,8 +337,6 @@ static int put_response(mem_event_t *mem
     RING_PUSH_RESPONSES(back_ring);
 
     mem_event_ring_unlock(mem_event);
-
-    return 0;
 }
 
 static int xenpaging_evict_page(xenpaging_t *paging,
@@ -400,9 +396,7 @@ static int xenpaging_resume_page(xenpagi
     int ret;
 
     /* Put the page info on the ring */
-    ret = put_response(&paging->mem_event, rsp);
-    if ( ret != 0 )
-        goto out;
+    put_response(&paging->mem_event, rsp);
 
     /* Notify policy of page being paged in */
     if ( notify_policy )
@@ -612,12 +606,7 @@ int main(int argc, char *argv[])
 
         while ( RING_HAS_UNCONSUMED_REQUESTS(&paging->mem_event.back_ring) )
         {
-            rc = get_request(&paging->mem_event, &req);
-            if ( rc != 0 )
-            {
-                ERROR("Error getting request");
-                goto out;
-            }
+            get_request(&paging->mem_event, &req);
 
             /* Check if the page has already been paged in */
             if ( test_and_clear_bit(req.gfn, paging->bitmap) )

[PATCH 05 of 12] xenpaging: catch xc_mem_paging_resume errors

[Olaf Hering]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1307437214 -7200
# Node ID 8eb07742f96854303ad7793f9319cd314dcf7be3
# Parent  c31636354b69164c06e86feed58f9713656b8f0c
xenpaging: catch xc_mem_paging_resume errors

In the unlikely event that xc_mem_paging_resume() fails, do not overwrite the
error with the return value from xc_evtchn_notify()

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r c31636354b69 -r 8eb07742f968 tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:12 2011 +0200
+++ b/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:14 2011 +0200
@@ -405,8 +405,9 @@ static int xenpaging_resume_page(xenpagi
     /* Tell Xen page is ready */
     ret = xc_mem_paging_resume(paging->xc_handle, paging->mem_event.domain_id,
                                rsp->gfn);
-    ret = xc_evtchn_notify(paging->mem_event.xce_handle,
-                           paging->mem_event.port);
+    if ( ret == 0 ) 
+        ret = xc_evtchn_notify(paging->mem_event.xce_handle,
+                               paging->mem_event.port);
 
  out:
     return ret;

[PATCH 06 of 12] xenpaging: remove local domain_id variable

[Olaf Hering]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1307437215 -7200
# Node ID 46c9f04365804c08a454b82e76119c43df4d7fa0
# Parent  8eb07742f96854303ad7793f9319cd314dcf7be3
xenpaging: remove local domain_id variable

Remove the local domain_id variable, it is already fetched from
paging->mem_event in other places.
Update the sprintf format string to use unsigned argument.

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r 8eb07742f968 -r 46c9f0436580 tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:14 2011 +0200
+++ b/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:15 2011 +0200
@@ -515,7 +515,6 @@ static int evict_victim(xenpaging_t *pag
 int main(int argc, char *argv[])
 {
     struct sigaction act;
-    domid_t domain_id;
     int num_pages;
     xenpaging_t *paging;
     xenpaging_victim_t *victims;
@@ -536,11 +535,10 @@ int main(int argc, char *argv[])
         return -1;
     }
 
-    domain_id = atoi(argv[1]);
     num_pages = atoi(argv[2]);
 
     /* Initialise domain paging */
-    paging = xenpaging_init(domain_id);
+    paging = xenpaging_init(atoi(argv[1]));
     if ( paging == NULL )
     {
         fprintf(stderr, "Error initialising paging");
@@ -548,10 +546,10 @@ int main(int argc, char *argv[])
     }
     xch = paging->xc_handle;
 
-    DPRINTF("starting %s %u %d\n", argv[0], domain_id, num_pages);
+    DPRINTF("starting %s %u %d\n", argv[0], paging->mem_event.domain_id, num_pages);
 
     /* Open file */
-    sprintf(filename, "page_cache_%d", domain_id);
+    sprintf(filename, "page_cache_%u", paging->mem_event.domain_id);
     fd = open(filename, open_flags, open_mode);
     if ( fd < 0 )
     {

[PATCH 07 of 12] xenpaging: move num_pages into xenpaging struct

[Olaf Hering]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1307437216 -7200
# Node ID 5aae4431bfc0970fd48f856fc4ede547ed4860f3
# Parent  46c9f04365804c08a454b82e76119c43df4d7fa0
xenpaging: move num_pages into xenpaging struct

Move num_pages into struct xenpaging.
num_pages will be used by the policy in a subsequent patch.
Also remove a memset, the victims array is allocated with calloc.

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r 46c9f0436580 -r 5aae4431bfc0 tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:15 2011 +0200
+++ b/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:16 2011 +0200
@@ -73,7 +73,7 @@ static void *init_page(void)
     return NULL;
 }
 
-static xenpaging_t *xenpaging_init(domid_t domain_id)
+static xenpaging_t *xenpaging_init(domid_t domain_id, int num_pages)
 {
     xenpaging_t *paging;
     xc_interface *xch;
@@ -215,6 +215,13 @@ static xenpaging_t *xenpaging_init(domid
     }
     DPRINTF("max_pages = %"PRIx64"\n", paging->domain_info->max_pages);
 
+    if ( num_pages < 0 || num_pages > paging->domain_info->max_pages )
+    {
+        num_pages = paging->domain_info->max_pages;
+        DPRINTF("setting num_pages to %d\n", num_pages);
+    }
+    paging->num_pages = num_pages;
+
     /* Initialise policy */
     rc = policy_init(paging);
     if ( rc != 0 )
@@ -515,7 +522,6 @@ static int evict_victim(xenpaging_t *pag
 int main(int argc, char *argv[])
 {
     struct sigaction act;
-    int num_pages;
     xenpaging_t *paging;
     xenpaging_victim_t *victims;
     mem_event_request_t req;
@@ -535,10 +541,8 @@ int main(int argc, char *argv[])
         return -1;
     }
 
-    num_pages = atoi(argv[2]);
-
     /* Initialise domain paging */
-    paging = xenpaging_init(atoi(argv[1]));
+    paging = xenpaging_init(atoi(argv[1]), atoi(argv[2]));
     if ( paging == NULL )
     {
         fprintf(stderr, "Error initialising paging");
@@ -546,7 +550,7 @@ int main(int argc, char *argv[])
     }
     xch = paging->xc_handle;
 
-    DPRINTF("starting %s %u %d\n", argv[0], paging->mem_event.domain_id, num_pages);
+    DPRINTF("starting %s %u %d\n", argv[0], paging->mem_event.domain_id, paging->num_pages);
 
     /* Open file */
     sprintf(filename, "page_cache_%u", paging->mem_event.domain_id);
@@ -557,12 +561,7 @@ int main(int argc, char *argv[])
         return 2;
     }
 
-    if ( num_pages < 0 || num_pages > paging->domain_info->max_pages )
-    {
-        num_pages = paging->domain_info->max_pages;
-        DPRINTF("setting num_pages to %d\n", num_pages);
-    }
-    victims = calloc(num_pages, sizeof(xenpaging_victim_t));
+    victims = calloc(paging->num_pages, sizeof(xenpaging_victim_t));
 
     /* ensure that if we get a signal, we'll do cleanup, then exit */
     act.sa_handler = close_handler;
@@ -574,8 +573,7 @@ int main(int argc, char *argv[])
     sigaction(SIGALRM, &act, NULL);
 
     /* Evict pages */
-    memset(victims, 0, sizeof(xenpaging_victim_t) * num_pages);
-    for ( i = 0; i < num_pages; i++ )
+    for ( i = 0; i < paging->num_pages; i++ )
     {
         rc = evict_victim(paging, &victims[i], fd, i);
         if ( rc == -ENOSPC )
@@ -611,13 +609,13 @@ int main(int argc, char *argv[])
             if ( test_and_clear_bit(req.gfn, paging->bitmap) )
             {
                 /* Find where in the paging file to read from */
-                for ( i = 0; i < num_pages; i++ )
+                for ( i = 0; i < paging->num_pages; i++ )
                 {
                     if ( victims[i].gfn == req.gfn )
                         break;
                 }
     
-                if ( i >= num_pages )
+                if ( i >= paging->num_pages )
                 {
                     DPRINTF("Couldn't find page %"PRIx64"\n", req.gfn);
                     goto out;
diff -r 46c9f0436580 -r 5aae4431bfc0 tools/xenpaging/xenpaging.h
--- a/tools/xenpaging/xenpaging.h	Tue Jun 07 11:00:15 2011 +0200
+++ b/tools/xenpaging/xenpaging.h	Tue Jun 07 11:00:16 2011 +0200
@@ -45,6 +45,7 @@ typedef struct xenpaging {
     unsigned long *bitmap;
 
     mem_event_t mem_event;
+    int num_pages;
     int policy_mru_size;
 } xenpaging_t;

[PATCH 08 of 12] xenpaging: start paging in the middle of gfn range

[Olaf Hering]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1307437217 -7200
# Node ID f5203dded3b13a33716ae50ef12d766c394f81f5
# Parent  5aae4431bfc0970fd48f856fc4ede547ed4860f3
xenpaging: start paging in the middle of gfn range

Set the starting gfn to somewhere in the middle of the gfn range to
avoid paging during BIOS startup. This can speedup booting of a guest.

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r 5aae4431bfc0 -r f5203dded3b1 tools/xenpaging/policy_default.c
--- a/tools/xenpaging/policy_default.c	Tue Jun 07 11:00:16 2011 +0200
+++ b/tools/xenpaging/policy_default.c	Tue Jun 07 11:00:17 2011 +0200
@@ -76,6 +76,10 @@ int policy_init(xenpaging_t *paging)
     /* Don't page out page 0 */
     set_bit(0, bitmap);
 
+    /* Start in the middle to avoid paging during BIOS startup */
+    current_gfn = max_pages / 2;
+    current_gfn -= paging->num_pages / 2;
+
  out:
     return rc;
 }

[PATCH 09 of 12] xenpaging: pass integer to xenpaging_populate_page

[Olaf Hering]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1307437218 -7200
# Node ID 48244bc8156ff8eca82ce9ab811516aae3d3fe32
# Parent  f5203dded3b13a33716ae50ef12d766c394f81f5
xenpaging: pass integer to xenpaging_populate_page

Pass gfn as integer to xenpaging_populate_page(). xc_map_foreign_pages()
takes a pointer to a list of gfns, but its a const pointer. So writing
the value back to the caller is not needed.

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r f5203dded3b1 -r 48244bc8156f tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:17 2011 +0200
+++ b/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:18 2011 +0200
@@ -421,27 +421,24 @@ static int xenpaging_resume_page(xenpagi
 }
 
 static int xenpaging_populate_page(xenpaging_t *paging,
-    uint64_t *gfn, int fd, int i)
+    xen_pfn_t gfn, int fd, int i)
 {
     xc_interface *xch = paging->xc_handle;
-    unsigned long _gfn;
     void *page;
     int ret;
     unsigned char oom = 0;
 
-    _gfn = *gfn;
-    DPRINTF("populate_page < gfn %lx pageslot %d\n", _gfn, i);
+    DPRINTF("populate_page < gfn %"PRI_xen_pfn" pageslot %d\n", gfn, i);
     do
     {
         /* Tell Xen to allocate a page for the domain */
-        ret = xc_mem_paging_prep(xch, paging->mem_event.domain_id,
-                                 _gfn);
+        ret = xc_mem_paging_prep(xch, paging->mem_event.domain_id, gfn);
         if ( ret != 0 )
         {
             if ( errno == ENOMEM )
             {
                 if ( oom++ == 0 )
-                    DPRINTF("ENOMEM while preparing gfn %lx\n", _gfn);
+                    DPRINTF("ENOMEM while preparing gfn %"PRI_xen_pfn"\n", gfn);
                 sleep(1);
                 continue;
             }
@@ -454,8 +451,7 @@ static int xenpaging_populate_page(xenpa
     /* Map page */
     ret = -EFAULT;
     page = xc_map_foreign_pages(xch, paging->mem_event.domain_id,
-                                PROT_READ | PROT_WRITE, &_gfn, 1);
-    *gfn = _gfn;
+                                PROT_READ | PROT_WRITE, &gfn, 1);
     if ( page == NULL )
     {
         ERROR("Error mapping page: page is null");
@@ -630,7 +626,7 @@ int main(int argc, char *argv[])
                 else
                 {
                     /* Populate the page */
-                    rc = xenpaging_populate_page(paging, &req.gfn, fd, i);
+                    rc = xenpaging_populate_page(paging, req.gfn, fd, i);
                     if ( rc != 0 )
                     {
                         ERROR("Error populating page");

[PATCH 10 of 12] xenpaging: add helper function for unlinking pagefile

[Olaf Hering]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1307437220 -7200
# Node ID fb445bd61233844f4b9d42b6eca172670f75eb98
# Parent  48244bc8156ff8eca82ce9ab811516aae3d3fe32
xenpaging: add helper function for unlinking pagefile

Unlink pagefile in the signal handler and also in the exit path.
This does not leave a stale pagefile if an error occoured.

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r 48244bc8156f -r fb445bd61233 tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:18 2011 +0200
+++ b/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:20 2011 +0200
@@ -41,11 +41,20 @@
 
 static char filename[80];
 static int interrupted;
+
+static void unlink_pagefile(void)
+{
+    if ( filename[0] )
+    {
+        unlink(filename);
+        filename[0] = '\0';
+    }
+}
+
 static void close_handler(int sig)
 {
     interrupted = sig;
-    if ( filename[0] )
-        unlink(filename);
+    unlink_pagefile();
 }
 
 static void *init_page(void)
@@ -679,6 +688,7 @@ int main(int argc, char *argv[])
 
  out:
     close(fd);
+    unlink_pagefile();
     free(victims);
 
     /* Tear down domain paging */

[PATCH 11 of 12] xenpaging: add watch thread to catch guest shutdown

[Olaf Hering]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1307437221 -7200
# Node ID 9484d35ec6e802aa3727cb6332e649b41e80a615
# Parent  fb445bd61233844f4b9d42b6eca172670f75eb98
xenpaging: add watch thread to catch guest shutdown

If xenpaging is started manually then no event is sent to xenpaging when
the guest is shutdown or rebooted.  Add a watch on the shutdown node to
leave the loop and gracefully shutdown the pager.

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r fb445bd61233 -r 9484d35ec6e8 tools/xenpaging/Makefile
--- a/tools/xenpaging/Makefile	Tue Jun 07 11:00:20 2011 +0200
+++ b/tools/xenpaging/Makefile	Tue Jun 07 11:00:21 2011 +0200
@@ -8,6 +8,7 @@ POLICY    = default
 
 SRC      :=
 SRCS     += file_ops.c xc.c xenpaging.c policy_$(POLICY).c
+SRCS     += watch.c
 
 CFLAGS   += -Werror
 CFLAGS   += -Wno-unused
diff -r fb445bd61233 -r 9484d35ec6e8 tools/xenpaging/watch.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/xenpaging/watch.c	Tue Jun 07 11:00:21 2011 +0200
@@ -0,0 +1,79 @@
+/* watch for guest shutdown in case xenpaging is started manually */
+#include <unistd.h>
+#include <pthread.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <xs.h>
+#include <xen/xen.h>
+
+struct watch_args {
+    domid_t domain_id;
+    void (*fn)(void);
+};
+
+static pthread_t watch_thread;
+static struct watch_args watch_args;
+static const char shutdown[] = "/control/shutdown";
+
+static void *watch_domain(void *arg)
+{
+    struct watch_args *wa = arg;
+    struct xs_handle *xs;
+    char *dom_path, *path, **vec;
+    unsigned int num;
+    size_t malloc_len;
+    bool ret;
+
+    xs = xs_daemon_open_readonly();
+    if ( xs == NULL )
+        goto exit;
+
+    dom_path = xs_get_domain_path(xs, wa->domain_id);
+    if ( dom_path == NULL )
+        goto close_exit;
+
+    malloc_len = strlen(dom_path) + strlen(shutdown) + 1;
+    path = malloc(malloc_len);
+    if ( path == NULL )
+        goto close_exit;
+
+    snprintf(path, malloc_len, "%s%s", dom_path, shutdown);
+
+    ret = xs_watch(xs, path, "");
+    if ( ret == true )
+    {
+        /* first watch fires right away */
+        vec = xs_read_watch(xs, &num);
+        free(vec);
+        /* wait for real event */
+        vec = xs_read_watch(xs, &num);
+        free(vec);
+        xs_unwatch(xs, path, "");
+    
+        /* notify pager */
+        wa->fn();
+    }
+
+    free(path);
+close_exit:
+    xs_daemon_close(xs);
+exit:
+    pthread_exit(NULL);
+}
+
+void create_watch_thread(domid_t domain_id, void (*fn)(void))
+{
+    watch_args.domain_id = domain_id;
+    watch_args.fn = fn;
+    pthread_create(&watch_thread, NULL, watch_domain, &watch_args);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-set-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End: 
+ */
diff -r fb445bd61233 -r 9484d35ec6e8 tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:20 2011 +0200
+++ b/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:21 2011 +0200
@@ -57,6 +57,11 @@ static void close_handler(int sig)
     unlink_pagefile();
 }
 
+static void set_interrupted_quit(void)
+{
+    interrupted = SIGQUIT;
+}
+
 static void *init_page(void)
 {
     void *buffer;
@@ -577,6 +582,9 @@ int main(int argc, char *argv[])
     sigaction(SIGINT,  &act, NULL);
     sigaction(SIGALRM, &act, NULL);
 
+    /* watch for shutdown of domain_id */
+    create_watch_thread(paging->mem_event.domain_id, set_interrupted_quit);
+
     /* Evict pages */
     for ( i = 0; i < paging->num_pages; i++ )
     {
diff -r fb445bd61233 -r 9484d35ec6e8 tools/xenpaging/xenpaging.h
--- a/tools/xenpaging/xenpaging.h	Tue Jun 07 11:00:20 2011 +0200
+++ b/tools/xenpaging/xenpaging.h	Tue Jun 07 11:00:21 2011 +0200
@@ -55,6 +55,7 @@ typedef struct xenpaging_victim {
     unsigned long gfn;
 } xenpaging_victim_t;
 
+extern void create_watch_thread(domid_t domain_id, void (*fn)(void));
 
 #endif // __XEN_PAGING_H__

Re: [PATCH 11 of 12] xenpaging: add watch thread to catch guest shutdown

[Ian Campbell]

On Tue, 2011-06-07 at 10:53 +0100, Olaf Hering wrote:
> # HG changeset patch
> # User Olaf Hering <olaf@aepfle.de>
> # Date 1307437221 -7200
> # Node ID 9484d35ec6e802aa3727cb6332e649b41e80a615
> # Parent  fb445bd61233844f4b9d42b6eca172670f75eb98
> xenpaging: add watch thread to catch guest shutdown
> 
> If xenpaging is started manually then no event is sent to xenpaging when
> the guest is shutdown or rebooted.  Add a watch on the shutdown node to
> leave the loop and gracefully shutdown the pager.
> 
> Signed-off-by: Olaf Hering <olaf@aepfle.de>

There are ways for a domain to shutdown which do not involve the
shutdown node.

The correct way to watch for domain shutdown is to watch the special
"@releaseDomain" node. IIRC this notifies you when _any_ domain has
shutdown so you need to check for the domain you are actually interested
in. Doing this also removes the need for the hacky extra xs_read_watch
which you have -- which seems very racy to me and is almost certainly
incorrect.

Lastly I don't think you need a new thread for this, you can integrate
the xs fd (from xs_fileno()) into your existing poll loop from
xc_wait_for_event_or_timeout (which is a terrible name for a function
which isn't in libxc, this should either be moved into the library or
renamed depending on it's actual use cases. Same for the other xc_* in
xenpaging...)

Ian.

> diff -r fb445bd61233 -r 9484d35ec6e8 tools/xenpaging/Makefile
> --- a/tools/xenpaging/Makefile	Tue Jun 07 11:00:20 2011 +0200
> +++ b/tools/xenpaging/Makefile	Tue Jun 07 11:00:21 2011 +0200
> @@ -8,6 +8,7 @@ POLICY    = default
>  
>  SRC      :=
>  SRCS     += file_ops.c xc.c xenpaging.c policy_$(POLICY).c
> +SRCS     += watch.c
>  
>  CFLAGS   += -Werror
>  CFLAGS   += -Wno-unused
> diff -r fb445bd61233 -r 9484d35ec6e8 tools/xenpaging/watch.c
> --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
> +++ b/tools/xenpaging/watch.c	Tue Jun 07 11:00:21 2011 +0200
> @@ -0,0 +1,79 @@
> +/* watch for guest shutdown in case xenpaging is started manually */
> +#include <unistd.h>
> +#include <pthread.h>
> +#include <string.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <xs.h>
> +#include <xen/xen.h>
> +
> +struct watch_args {
> +    domid_t domain_id;
> +    void (*fn)(void);
> +};
> +
> +static pthread_t watch_thread;
> +static struct watch_args watch_args;
> +static const char shutdown[] = "/control/shutdown";
> +
> +static void *watch_domain(void *arg)
> +{
> +    struct watch_args *wa = arg;
> +    struct xs_handle *xs;
> +    char *dom_path, *path, **vec;
> +    unsigned int num;
> +    size_t malloc_len;
> +    bool ret;
> +
> +    xs = xs_daemon_open_readonly();
> +    if ( xs == NULL )
> +        goto exit;
> +
> +    dom_path = xs_get_domain_path(xs, wa->domain_id);
> +    if ( dom_path == NULL )
> +        goto close_exit;
> +
> +    malloc_len = strlen(dom_path) + strlen(shutdown) + 1;
> +    path = malloc(malloc_len);
> +    if ( path == NULL )
> +        goto close_exit;
> +
> +    snprintf(path, malloc_len, "%s%s", dom_path, shutdown);
> +
> +    ret = xs_watch(xs, path, "");
> +    if ( ret == true )
> +    {
> +        /* first watch fires right away */
> +        vec = xs_read_watch(xs, &num);
> +        free(vec);
> +        /* wait for real event */
> +        vec = xs_read_watch(xs, &num);
> +        free(vec);
> +        xs_unwatch(xs, path, "");
> +    
> +        /* notify pager */
> +        wa->fn();
> +    }
> +
> +    free(path);
> +close_exit:
> +    xs_daemon_close(xs);
> +exit:
> +    pthread_exit(NULL);
> +}
> +
> +void create_watch_thread(domid_t domain_id, void (*fn)(void))
> +{
> +    watch_args.domain_id = domain_id;
> +    watch_args.fn = fn;
> +    pthread_create(&watch_thread, NULL, watch_domain, &watch_args);
> +}
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-set-style: "BSD"
> + * c-basic-offset: 4
> + * indent-tabs-mode: nil
> + * End: 
> + */
> diff -r fb445bd61233 -r 9484d35ec6e8 tools/xenpaging/xenpaging.c
> --- a/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:20 2011 +0200
> +++ b/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:21 2011 +0200
> @@ -57,6 +57,11 @@ static void close_handler(int sig)
>      unlink_pagefile();
>  }
>  
> +static void set_interrupted_quit(void)
> +{
> +    interrupted = SIGQUIT;
> +}
> +
>  static void *init_page(void)
>  {
>      void *buffer;
> @@ -577,6 +582,9 @@ int main(int argc, char *argv[])
>      sigaction(SIGINT,  &act, NULL);
>      sigaction(SIGALRM, &act, NULL);
>  
> +    /* watch for shutdown of domain_id */
> +    create_watch_thread(paging->mem_event.domain_id, set_interrupted_quit);
> +
>      /* Evict pages */
>      for ( i = 0; i < paging->num_pages; i++ )
>      {
> diff -r fb445bd61233 -r 9484d35ec6e8 tools/xenpaging/xenpaging.h
> --- a/tools/xenpaging/xenpaging.h	Tue Jun 07 11:00:20 2011 +0200
> +++ b/tools/xenpaging/xenpaging.h	Tue Jun 07 11:00:21 2011 +0200
> @@ -55,6 +55,7 @@ typedef struct xenpaging_victim {
>      unsigned long gfn;
>  } xenpaging_victim_t;
>  
> +extern void create_watch_thread(domid_t domain_id, void (*fn)(void));
>  
>  #endif // __XEN_PAGING_H__
>  
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

Re: [PATCH 11 of 12] xenpaging: add watch thread to catch guest shutdown

[Olaf Hering]

On Tue, Jun 07, Ian Campbell wrote:

> The correct way to watch for domain shutdown is to watch the special
> "@releaseDomain" node. IIRC this notifies you when _any_ domain has
> shutdown so you need to check for the domain you are actually interested
> in. Doing this also removes the need for the hacky extra xs_read_watch
> which you have -- which seems very racy to me and is almost certainly
> incorrect.

Thanks for the feedback, I have updated my patch to use this interface.

> Lastly I don't think you need a new thread for this, you can integrate
> the xs fd (from xs_fileno()) into your existing poll loop from
> xc_wait_for_event_or_timeout (which is a terrible name for a function
> which isn't in libxc, this should either be moved into the library or
> renamed depending on it's actual use cases. Same for the other xc_* in
> xenpaging...)

All of xc.c can be removed. If patches 1-10 are ok, can you apply them?

I will send another series to remove xc.c, which will also contain the
changes from patch 11 and 12.

Olaf

[PATCH 12 of 12] xenpaging: implement stopping of pager by sending SIGTERM/SIGINT

[Olaf Hering]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1307437222 -7200
# Node ID 168eef309cc99a5bebed230a54f337b6692c112d
# Parent  9484d35ec6e802aa3727cb6332e649b41e80a615
xenpaging: implement stopping of pager by sending SIGTERM/SIGINT

Write all paged-out pages back into the guest if the pager is
interrupted by ctrl-c or if it receives SIGTERM.

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r 9484d35ec6e8 -r 168eef309cc9 tools/xenpaging/Makefile
--- a/tools/xenpaging/Makefile	Tue Jun 07 11:00:21 2011 +0200
+++ b/tools/xenpaging/Makefile	Tue Jun 07 11:00:22 2011 +0200
@@ -9,6 +9,7 @@ POLICY    = default
 SRC      :=
 SRCS     += file_ops.c xc.c xenpaging.c policy_$(POLICY).c
 SRCS     += watch.c
+SRCS     += pagein.c
 
 CFLAGS   += -Werror
 CFLAGS   += -Wno-unused
diff -r 9484d35ec6e8 -r 168eef309cc9 tools/xenpaging/pagein.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/xenpaging/pagein.c	Tue Jun 07 11:00:22 2011 +0200
@@ -0,0 +1,68 @@
+/* Trigger a page-in in a separate thread-of-execution to avoid deadlock */
+#include <pthread.h>
+#include "xc.h"
+
+struct page_in_args {
+    domid_t dom;
+    xc_interface *xch;
+};
+
+static struct page_in_args page_in_args;
+static unsigned long page_in_gfn;
+static unsigned int page_in_possible;
+
+static pthread_t page_in_thread;
+static pthread_cond_t page_in_cond = PTHREAD_COND_INITIALIZER;
+static pthread_mutex_t page_in_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+static void *page_in(void *arg)
+{
+    struct page_in_args *pia = arg;
+    void *page;
+    xen_pfn_t gfn;
+
+    while (1)
+    {
+        pthread_mutex_lock(&page_in_mutex);
+        while (!page_in_gfn)
+            pthread_cond_wait(&page_in_cond, &page_in_mutex);
+        gfn = page_in_gfn;
+        page_in_gfn = 0;
+        pthread_mutex_unlock(&page_in_mutex);
+
+        /* Ignore errors */
+        page = xc_map_foreign_pages(pia->xch, pia->dom, PROT_READ, &gfn, 1);
+        if (page)
+            munmap(page, PAGE_SIZE);
+    }
+    page_in_possible = 0;
+    pthread_exit(NULL);
+}
+
+void page_in_trigger(unsigned long gfn)
+{
+    if (!page_in_possible)
+        return;
+
+    pthread_mutex_lock(&page_in_mutex);
+    page_in_gfn = gfn;
+    pthread_mutex_unlock(&page_in_mutex);
+    pthread_cond_signal(&page_in_cond);
+}
+
+void create_page_in_thread(domid_t domain_id, xc_interface *xch)
+{
+    page_in_args.dom = domain_id;
+    page_in_args.xch = xch;
+    if (pthread_create(&page_in_thread, NULL, page_in, &page_in_args) == 0)
+        page_in_possible = 1;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-set-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End: 
+ */
diff -r 9484d35ec6e8 -r 168eef309cc9 tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:21 2011 +0200
+++ b/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:22 2011 +0200
@@ -585,6 +585,9 @@ int main(int argc, char *argv[])
     /* watch for shutdown of domain_id */
     create_watch_thread(paging->mem_event.domain_id, set_interrupted_quit);
 
+    /* listen for page-in events to stop pager */
+    create_page_in_thread(paging->mem_event.domain_id, xch);
+
     /* Evict pages */
     for ( i = 0; i < paging->num_pages; i++ )
     {
@@ -600,7 +603,7 @@ int main(int argc, char *argv[])
     DPRINTF("%d pages evicted. Done.\n", i);
 
     /* Swap pages in and out */
-    while ( !interrupted )
+    while ( 1 )
     {
         /* Wait for Xen to signal that a page needs paged in */
         rc = xc_wait_for_event_or_timeout(xch, paging->mem_event.xce_handle, 100);
@@ -663,8 +666,12 @@ int main(int argc, char *argv[])
                     goto out;
                 }
 
-                /* Evict a new page to replace the one we just paged in */
-                evict_victim(paging, &victims[i], fd, i);
+                /* Evict a new page to replace the one we just paged in,
+                 * or clear this pagefile slot on exit */
+                if ( interrupted )
+                    victims[i].gfn = INVALID_MFN;
+                else
+                    evict_victim(paging, &victims[i], fd, i);
             }
             else
             {
@@ -691,6 +698,28 @@ int main(int argc, char *argv[])
                 }
             }
         }
+
+        /* Write all pages back into the guest */
+        if ( interrupted == SIGTERM || interrupted == SIGINT )
+        {
+            for ( i = 0; i < paging->domain_info->max_pages; i++ )
+            {
+                if ( test_bit(i, paging->bitmap) )
+                {
+                    page_in_trigger(i);
+                    break;
+                }
+            }
+            /* If no more pages to process, exit loop */
+            if ( i == paging->domain_info->max_pages )
+                break;
+        }
+        else
+        {
+            /* Exit on any other signal */
+            if ( interrupted )
+                break;
+        }
     }
     DPRINTF("xenpaging got signal %d\n", interrupted);
 
diff -r 9484d35ec6e8 -r 168eef309cc9 tools/xenpaging/xenpaging.h
--- a/tools/xenpaging/xenpaging.h	Tue Jun 07 11:00:21 2011 +0200
+++ b/tools/xenpaging/xenpaging.h	Tue Jun 07 11:00:22 2011 +0200
@@ -57,6 +57,9 @@ typedef struct xenpaging_victim {
 
 extern void create_watch_thread(domid_t domain_id, void (*fn)(void));
 
+extern void create_page_in_thread(domid_t domain_id, xc_interface *xch);
+extern void page_in_trigger(unsigned long gfn);
+
 #endif // __XEN_PAGING_H__

Re: [PATCH 00 of 12] xenpaging fixes for xen-unstable

[Keir Fraser]

On 07/06/2011 10:53, "Olaf Hering" <olaf@aepfle.de> wrote:

> The following series of changes for xenpaging fixes a few bugs, does some
> cleanup and adds two new features to the pager.
> It is now possible to run the pager manually and stop it with ctrl-c, without
> corrupting the guest. A shutdown of a guest is also catched with a xenstore
> watch.
> 
> Please review and apply.

I'll leave these patches for a tools maintainer to apply.

Once they're in, what is left to do? Do you need help with the in-Xen
waitqueue stuff? Do you have test cases that fail, a private patch queue,
etc?

 -- Keir

> Olaf
> 
>  tools/xenpaging/Makefile         |    2
>  tools/xenpaging/pagein.c         |   68 +++++++++++++++++++
>  tools/xenpaging/policy_default.c |    4 +
>  tools/xenpaging/watch.c          |   79 ++++++++++++++++++++++
>  tools/xenpaging/xenpaging.c      |  138
> ++++++++++++++++++++++-----------------
>  tools/xenpaging/xenpaging.h      |    5 +
>  xen/arch/x86/mm/p2m.c            |    1
>  7 files changed, 238 insertions(+), 59 deletions(-)
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

Re: [PATCH 00 of 12] xenpaging fixes for xen-unstable

[Olaf Hering]

On Tue, Jun 07, Keir Fraser wrote:

> Once they're in, what is left to do? Do you need help with the in-Xen
> waitqueue stuff? Do you have test cases that fail, a private patch queue,
> etc?

Keir,

I have no new patches, just returned to xenpaging end of last week.
A few months ago I collected my TODO list below.

One thing that I would need help with is the machine_to_phys_mapping[]
handling, an attempt to fix it was reverted before the 4.1 release. See
the thread in the URL below.

My testcase was a SLES11SP1 pv-on-hvm guest, rebooted in an endless
loop. That catched all of the issues. With the
waitqueue/HVMCOPY_gfn_paged_out issue its best to customize the
xenpaging policy to page the range of gfns were the guest pagetables are
stored.

I will send a series of patches to try later.

Olaf


Todo:
- implement xl support
- implement stopping of xenpaging
- implement live migration
- implement config option for XENPAGING_DEBUG and XENPAGING_POLICY_MRU_SIZE
- implement config option for xenpaging_dir
- implement better starting gfn in xenpaging policy
  an initial gfn number in the middle of the gfn range may avoid page-ins
  during BIOS startup
- fix machine_to_phys_mapping[] array handling during page deallocation
  the gfn of a released page must be maintained properly in the array
  http://lists.xensource.com/archives/html/xen-devel/2011-01/msg00824.html
- fix HVMCOPY_gfn_paged_out handling
  some callers of __hvm_copy() do not handle HVMCOPY_gfn_paged_out, such
  as hypercalls and the MMIO emulation
  the recently added waitqueue feature in Xen 4.1 should be used
- remove all retry code from gfn_to_mfn() calls
  use the waitqueue feature to hide page-in from the caller and cover
  all cases where a retry is currently missing
- do not bounce p2mt to xenpaging
  p2m_mem_paging_populate/p2m_mem_paging_resume dont make use of p2mt
- cleanup typeof gfn which is passed around in xenpaging
  unsigned long, uint64_t, xen_pfn_t
- cleanup return types of functions
  some functions return 0 unconditionally, could be void
- remove srand function

Re: [PATCH 00 of 12] xenpaging fixes for xen-unstable

[Keir Fraser]

On 07/06/2011 14:38, "Olaf Hering" <olaf@aepfle.de> wrote:

> On Tue, Jun 07, Keir Fraser wrote:
> 
>> Once they're in, what is left to do? Do you need help with the in-Xen
>> waitqueue stuff? Do you have test cases that fail, a private patch queue,
>> etc?
> 
> Keir,
> 
> I have no new patches, just returned to xenpaging end of last week.
> A few months ago I collected my TODO list below.
> 
> One thing that I would need help with is the machine_to_phys_mapping[]
> handling, an attempt to fix it was reverted before the 4.1 release. See
> the thread in the URL below.

I'm taking a look at this. The hard way I describe in the referenced thread
seemed like a mistake when I tried it, so I'll sort out a simpler fix for
the original patch.

 -- Keir

> My testcase was a SLES11SP1 pv-on-hvm guest, rebooted in an endless
> loop. That catched all of the issues. With the
> waitqueue/HVMCOPY_gfn_paged_out issue its best to customize the
> xenpaging policy to page the range of gfns were the guest pagetables are
> stored.
> 
> I will send a series of patches to try later.
> 
> Olaf
> 
> 
> Todo:
> - implement xl support
> - implement stopping of xenpaging
> - implement live migration
> - implement config option for XENPAGING_DEBUG and XENPAGING_POLICY_MRU_SIZE
> - implement config option for xenpaging_dir
> - implement better starting gfn in xenpaging policy
>   an initial gfn number in the middle of the gfn range may avoid page-ins
>   during BIOS startup
> - fix machine_to_phys_mapping[] array handling during page deallocation
>   the gfn of a released page must be maintained properly in the array
>   http://lists.xensource.com/archives/html/xen-devel/2011-01/msg00824.html
> - fix HVMCOPY_gfn_paged_out handling
>   some callers of __hvm_copy() do not handle HVMCOPY_gfn_paged_out, such
>   as hypercalls and the MMIO emulation
>   the recently added waitqueue feature in Xen 4.1 should be used
> - remove all retry code from gfn_to_mfn() calls
>   use the waitqueue feature to hide page-in from the caller and cover
>   all cases where a retry is currently missing
> - do not bounce p2mt to xenpaging
>   p2m_mem_paging_populate/p2m_mem_paging_resume dont make use of p2mt
> - cleanup typeof gfn which is passed around in xenpaging
>   unsigned long, uint64_t, xen_pfn_t
> - cleanup return types of functions
>   some functions return 0 unconditionally, could be void
> - remove srand function
> 

Re: [PATCH 00 of 12] xenpaging fixes for xen-unstable

[Keir Fraser]

On 07/06/2011 14:38, "Olaf Hering" <olaf@aepfle.de> wrote:

> On Tue, Jun 07, Keir Fraser wrote:
> 
>> Once they're in, what is left to do? Do you need help with the in-Xen
>> waitqueue stuff? Do you have test cases that fail, a private patch queue,
>> etc?
> 
> Keir,
> 
> I have no new patches, just returned to xenpaging end of last week.
> A few months ago I collected my TODO list below.
> 
> One thing that I would need help with is the machine_to_phys_mapping[]
> handling, an attempt to fix it was reverted before the 4.1 release. See
> the thread in the URL below.

I've reapplied this as xen-unstable:23507.

 -- Keir

> My testcase was a SLES11SP1 pv-on-hvm guest, rebooted in an endless
> loop. That catched all of the issues. With the
> waitqueue/HVMCOPY_gfn_paged_out issue its best to customize the
> xenpaging policy to page the range of gfns were the guest pagetables are
> stored.
> 
> I will send a series of patches to try later.
> 
> Olaf
> 
> 
> Todo:
> - implement xl support
> - implement stopping of xenpaging
> - implement live migration
> - implement config option for XENPAGING_DEBUG and XENPAGING_POLICY_MRU_SIZE
> - implement config option for xenpaging_dir
> - implement better starting gfn in xenpaging policy
>   an initial gfn number in the middle of the gfn range may avoid page-ins
>   during BIOS startup
> - fix machine_to_phys_mapping[] array handling during page deallocation
>   the gfn of a released page must be maintained properly in the array
>   http://lists.xensource.com/archives/html/xen-devel/2011-01/msg00824.html
> - fix HVMCOPY_gfn_paged_out handling
>   some callers of __hvm_copy() do not handle HVMCOPY_gfn_paged_out, such
>   as hypercalls and the MMIO emulation
>   the recently added waitqueue feature in Xen 4.1 should be used
> - remove all retry code from gfn_to_mfn() calls
>   use the waitqueue feature to hide page-in from the caller and cover
>   all cases where a retry is currently missing
> - do not bounce p2mt to xenpaging
>   p2m_mem_paging_populate/p2m_mem_paging_resume dont make use of p2mt
> - cleanup typeof gfn which is passed around in xenpaging
>   unsigned long, uint64_t, xen_pfn_t
> - cleanup return types of functions
>   some functions return 0 unconditionally, could be void
> - remove srand function
> 

Re: [PATCH 00 of 12] xenpaging fixes for xen-unstable

[Olaf Hering]

On Fri, Jun 10, Keir Fraser wrote:

> On 07/06/2011 14:38, "Olaf Hering" <olaf@aepfle.de> wrote:
> 
> > On Tue, Jun 07, Keir Fraser wrote:
> > 
> >> Once they're in, what is left to do? Do you need help with the in-Xen
> >> waitqueue stuff? Do you have test cases that fail, a private patch queue,
> >> etc?
> > 
> > Keir,
> > 
> > I have no new patches, just returned to xenpaging end of last week.
> > A few months ago I collected my TODO list below.
> > 
> > One thing that I would need help with is the machine_to_phys_mapping[]
> > handling, an attempt to fix it was reverted before the 4.1 release. See
> > the thread in the URL below.
> 
> I've reapplied this as xen-unstable:23507.

Thanks Keir.

But the change breaks 32bit builds:

prelink.o: In function `populate_physmap':
/usr/src/packages/BUILD/xen-unstable.hg-4.2.23508/xen/common/memory.c:155: undefined reference to `machine_to_phys_mapping_valid'
prelink.o: In function `memory_exchange':
/usr/src/packages/BUILD/xen-unstable.hg-4.2.23508/xen/common/memory.c:491: undefined reference to `machine_to_phys_mapping_valid'
prelink.o: In function `free_heap_pages':
/usr/src/packages/BUILD/xen-unstable.hg-4.2.23508/xen/common/page_alloc.c:544: undefined reference to `machine_to_phys_mapping_valid'
prelink.o: In function `share_xen_page_with_guest':
/usr/src/packages/BUILD/xen-unstable.hg-4.2.23508/xen/arch/x86/mm.c:440: undefined reference to `machine_to_phys_mapping_valid'
prelink.o: In function `do_mmu_update':
/usr/src/packages/BUILD/xen-unstable.hg-4.2.23508/xen/arch/x86/mm.c:3688: undefined reference to `machine_to_phys_mapping_valid'
prelink.o:/usr/src/packages/BUILD/xen-unstable.hg-4.2.23508/xen/arch/x86/mm/p2m.c:373: more undefined references to `machine_to_phys_mapping_valid' follow

Re: [PATCH 00 of 12] xenpaging fixes for xen-unstable

[Keir Fraser]

On 10/06/2011 12:27, "Olaf Hering" <olaf@aepfle.de> wrote:

> On Fri, Jun 10, Keir Fraser wrote:
> 
>> On 07/06/2011 14:38, "Olaf Hering" <olaf@aepfle.de> wrote:
>> 
>>> On Tue, Jun 07, Keir Fraser wrote:
>>> 
>>>> Once they're in, what is left to do? Do you need help with the in-Xen
>>>> waitqueue stuff? Do you have test cases that fail, a private patch queue,
>>>> etc?
>>> 
>>> Keir,
>>> 
>>> I have no new patches, just returned to xenpaging end of last week.
>>> A few months ago I collected my TODO list below.
>>> 
>>> One thing that I would need help with is the machine_to_phys_mapping[]
>>> handling, an attempt to fix it was reverted before the 4.1 release. See
>>> the thread in the URL below.
>> 
>> I've reapplied this as xen-unstable:23507.
> 
> Thanks Keir.
> 
> But the change breaks 32bit builds:

Thanks, fixed by xen-unstable:23509.

 -- Keir

> prelink.o: In function `populate_physmap':
> /usr/src/packages/BUILD/xen-unstable.hg-4.2.23508/xen/common/memory.c:155:
> undefined reference to `machine_to_phys_mapping_valid'
> prelink.o: In function `memory_exchange':
> /usr/src/packages/BUILD/xen-unstable.hg-4.2.23508/xen/common/memory.c:491:
> undefined reference to `machine_to_phys_mapping_valid'
> prelink.o: In function `free_heap_pages':
> /usr/src/packages/BUILD/xen-unstable.hg-4.2.23508/xen/common/page_alloc.c:544:
> undefined reference to `machine_to_phys_mapping_valid'
> prelink.o: In function `share_xen_page_with_guest':
> /usr/src/packages/BUILD/xen-unstable.hg-4.2.23508/xen/arch/x86/mm.c:440:
> undefined reference to `machine_to_phys_mapping_valid'
> prelink.o: In function `do_mmu_update':
> /usr/src/packages/BUILD/xen-unstable.hg-4.2.23508/xen/arch/x86/mm.c:3688:
> undefined reference to `machine_to_phys_mapping_valid'
> prelink.o:/usr/src/packages/BUILD/xen-unstable.hg-4.2.23508/xen/arch/x86/mm/p2
> m.c:373: more undefined references to `machine_to_phys_mapping_valid' follow
>