Guest memory size that's larger than host physical RAM can cause swap deaths on
the host so warn the user about it.
Cc: Asias He <asias.hejun@xxxxxxxxx>
Cc: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Prasad Joshi <prasadjoshi124@xxxxxxxxx>
Cc: Sasha Levin <levinsasha928@xxxxxxxxx>
Suggested-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Pekka Enberg <penberg@xxxxxxxxxx>
---
tools/kvm/kvm-run.c | 23 ++++++++++++++++-------
1 files changed, 16 insertions(+), 7 deletions(-)
diff --git a/tools/kvm/kvm-run.c b/tools/kvm/kvm-run.c
index b9cdec2..764a242 100644
--- a/tools/kvm/kvm-run.c
+++ b/tools/kvm/kvm-run.c
@@ -213,6 +213,18 @@ static void kernel_usage_with_options(void)
fprintf(stderr, "\nPlease see 'kvm run --help' for more options.\n\n");
}
+static u64 host_ram_size(void)
+{
+ long page_size;
+ long nr_pages;
+
+ nr_pages = sysconf(_SC_PHYS_PAGES);
+
+ page_size = sysconf(_SC_PAGE_SIZE);
+
+ return (nr_pages * page_size) >> MB_SHIFT;
+}
+
/*
* If user didn't specify how much memory it wants to allocate for the guest,
* avoid filling the whole host RAM.
@@ -222,17 +234,11 @@ static void kernel_usage_with_options(void)
static u64 get_ram_size(int nr_cpus)
{
long available;
- long page_size;
- long nr_pages;
long ram_size;
ram_size = 64 * (nr_cpus + 3);
- nr_pages = sysconf(_SC_PHYS_PAGES);
-
- page_size = sysconf(_SC_PAGE_SIZE);
-
- available = ((nr_pages * page_size) >> MB_SHIFT) * RAM_SIZE_RATIO;
+ available = host_ram_size() * RAM_SIZE_RATIO;
if (ram_size > available)
ram_size = available;
@@ -364,6 +370,9 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
if (ram_size < MIN_RAM_SIZE_MB)
die("Not enough memory specified: %lluMB (min %lluMB)", ram_size, MIN_RAM_SIZE_MB);
+ if (ram_size > host_ram_size())
+ warning("Guest memory size %lluMB exceeds host physical RAM size %lluMB", ram_size, host_ram_size());
+
ram_size <<= MB_SHIFT;
if (!kvm_dev)
--
1.7.0.4
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