[Xen-changelog] [xen master] libxl: remove freemem_slack

[patchbot@xxxxxxx]

commit c26f92b8fce3c9df17f7ef035b54d97cbe931c7a
Author:     Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
AuthorDate: Wed Feb 25 15:07:25 2015 +0000
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Mon Mar 2 14:00:15 2015 +0000

    libxl: remove freemem_slack
    
    freemem_slack accounts for the amount of memory to be left free in the
    system because empirical experiments seem to demonstrate that is needed
    for "stability reasons".
    
    As we don't have any actual data on these stability issues, remove it.
    
    Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
    CC: mlatimer@xxxxxxxx
    CC: ian.campbell@xxxxxxxxxx
    Acked-by: Mike Latimer <mlatimer@xxxxxxxx>
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 tools/libxl/libxl.c |   59 +++-----------------------------------------------
 1 files changed, 4 insertions(+), 55 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index b9a1941..a68f6ef 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -4592,13 +4592,11 @@ static int libxl__fill_dom0_memory_info(libxl__gc *gc, 
uint32_t *target_memkb,
     int rc;
     libxl_dominfo info;
     libxl_physinfo physinfo;
-    char *target = NULL, *staticmax = NULL, *freememslack = NULL, *endptr = 
NULL;
+    char *target = NULL, *staticmax = NULL, *endptr = NULL;
     char *target_path = "/local/domain/0/memory/target";
     char *max_path = "/local/domain/0/memory/static-max";
-    char *free_mem_slack_path = "/local/domain/0/memory/freemem-slack";
     xs_transaction_t t;
     libxl_ctx *ctx = libxl__gc_owner(gc);
-    uint32_t free_mem_slack_kb = 0;
 
     libxl_dominfo_init(&info);
 
@@ -4607,8 +4605,7 @@ retry_transaction:
 
     target = libxl__xs_read(gc, t, target_path);
     staticmax = libxl__xs_read(gc, t, max_path);
-    freememslack = libxl__xs_read(gc, t, free_mem_slack_path);
-    if (target && staticmax && freememslack) {
+    if (target && staticmax) {
         rc = 0;
         goto out;
     }
@@ -4655,15 +4652,6 @@ retry_transaction:
         *max_memkb = (uint32_t) info.max_memkb;
     }
 
-    if (freememslack == NULL) {
-        free_mem_slack_kb = (uint32_t) (PAGE_TO_MEMKB(physinfo.total_pages) -
-                info.current_memkb);
-        /* From empirical measurements the free_mem_slack shouldn't be more
-         * than 15% of the total memory present on the system. */
-        if (free_mem_slack_kb > PAGE_TO_MEMKB(physinfo.total_pages) * 0.15)
-            free_mem_slack_kb = PAGE_TO_MEMKB(physinfo.total_pages) * 0.15;
-        libxl__xs_write(gc, t, free_mem_slack_path, "%"PRIu32, 
free_mem_slack_kb);
-    }
     rc = 0;
 
 out:
@@ -4678,33 +4666,6 @@ out:
     return rc;
 }
 
-/* returns how much memory should be left free in the system */
-static int libxl__get_free_memory_slack(libxl__gc *gc, uint32_t 
*free_mem_slack)
-{
-    int rc;
-    char *free_mem_slack_path = "/local/domain/0/memory/freemem-slack";
-    char *free_mem_slack_s, *endptr;
-    uint32_t target_memkb, max_memkb;
-
-retry:
-    free_mem_slack_s = libxl__xs_read(gc, XBT_NULL, free_mem_slack_path);
-    if (!free_mem_slack_s) {
-        rc = libxl__fill_dom0_memory_info(gc, &target_memkb, &max_memkb);
-        if (rc < 0)
-            return rc;
-        goto retry;
-    } else {
-        *free_mem_slack = strtoul(free_mem_slack_s, &endptr, 10);
-        if (*endptr != '\0') {
-            LIBXL__LOG_ERRNO(gc->owner, LIBXL__LOG_ERROR,
-                    "invalid free_mem_slack %s from %s\n",
-                    free_mem_slack_s, free_mem_slack_path);
-            return ERROR_FAIL;
-        }
-    }
-    return 0;
-}
-
 int libxl_set_memory_target(libxl_ctx *ctx, uint32_t domid,
         int32_t target_memkb, int relative, int enforce)
 {
@@ -4953,20 +4914,13 @@ int libxl_get_free_memory(libxl_ctx *ctx, uint32_t 
*memkb)
 {
     int rc = 0;
     libxl_physinfo info;
-    uint32_t freemem_slack;
     GC_INIT(ctx);
 
     rc = libxl_get_physinfo(ctx, &info);
     if (rc < 0)
         goto out;
-    rc = libxl__get_free_memory_slack(gc, &freemem_slack);
-    if (rc < 0)
-        goto out;
 
-    if ((info.free_pages + info.scrub_pages) * 4 > freemem_slack)
-        *memkb = (info.free_pages + info.scrub_pages) * 4 - freemem_slack;
-    else
-        *memkb = 0;
+    *memkb = (info.free_pages + info.scrub_pages) * 4;
 
 out:
     GC_FREE;
@@ -4978,18 +4932,13 @@ int libxl_wait_for_free_memory(libxl_ctx *ctx, uint32_t 
domid, uint32_t
 {
     int rc = 0;
     libxl_physinfo info;
-    uint32_t freemem_slack;
     GC_INIT(ctx);
 
-    rc = libxl__get_free_memory_slack(gc, &freemem_slack);
-    if (rc < 0)
-        goto out;
     while (wait_secs > 0) {
         rc = libxl_get_physinfo(ctx, &info);
         if (rc < 0)
             goto out;
-        if (info.free_pages * 4 >= freemem_slack &&
-            info.free_pages * 4 - freemem_slack >= memory_kb) {
+        if (info.free_pages * 4 >= memory_kb) {
             rc = 0;
             goto out;
         }
--
generated by git-patchbot for /home/xen/git/xen.git#master

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