In order to reduce the memory footprint we map into memory
the initrd using g_mapped_file_new() instead of reading it.
In this way we can share the initrd pages between multiple
instances of QEMU.
Suggested-by: Paolo Bonzini <pbonz...@redhat.com>
Signed-off-by: Stefano Garzarella <sgarz...@redhat.com>
---
v3:
- renamed 'GMappedFile *gmf' in 'GMappedFile *mapped_filed' for readability
- stored the initrd GMappedFile* in PCMachineState to avoid Coverity
issue [Paolo]
---
hw/i386/pc.c | 17 +++++++++++++----
include/hw/i386/pc.h | 1 +
2 files changed, 14 insertions(+), 4 deletions(-)
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 549c437050..96f6b89f70 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1241,17 +1241,21 @@ static void load_linux(PCMachineState *pcms,
/* load initrd */
if (initrd_filename) {
+ GMappedFile *mapped_file;
gsize initrd_size;
gchar *initrd_data;
GError *gerr = NULL;
- if (!g_file_get_contents(initrd_filename, &initrd_data,
- &initrd_size, &gerr)) {
+ mapped_file = g_mapped_file_new(initrd_filename, false, &gerr);
+ if (!mapped_file) {
fprintf(stderr, "qemu: error reading initrd %s: %s\n",
initrd_filename, gerr->message);
exit(1);
}
+ pcms->initrd_mapped_file = mapped_file;
+ initrd_data = g_mapped_file_get_contents(mapped_file);
+ initrd_size = g_mapped_file_get_length(mapped_file);
initrd_max = pcms->below_4g_mem_size - pcmc->acpi_data_size -
1;
if (initrd_size >= initrd_max) {
fprintf(stderr, "qemu: initrd is too large, cannot
support."
@@ -1378,6 +1382,7 @@ static void load_linux(PCMachineState *pcms,
/* load initrd */
if (initrd_filename) {
+ GMappedFile *mapped_file;
gsize initrd_size;
gchar *initrd_data;
GError *gerr = NULL;
@@ -1387,12 +1392,16 @@ static void load_linux(PCMachineState *pcms,
exit(1);
}
- if (!g_file_get_contents(initrd_filename, &initrd_data,
- &initrd_size, &gerr)) {
+ mapped_file = g_mapped_file_new(initrd_filename, false, &gerr);
+ if (!mapped_file) {
fprintf(stderr, "qemu: error reading initrd %s: %s\n",
initrd_filename, gerr->message);
exit(1);
}
+ pcms->initrd_mapped_file = mapped_file;
+
+ initrd_data = g_mapped_file_get_contents(mapped_file);
+ initrd_size = g_mapped_file_get_length(mapped_file);
if (initrd_size >= initrd_max) {
fprintf(stderr, "qemu: initrd is too large, cannot support."
"(max: %"PRIu32", need %"PRId64")\n",
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 859b64c51d..44edc6955e 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -42,6 +42,7 @@ struct PCMachineState {
FWCfgState *fw_cfg;
qemu_irq *gsi;
PFlashCFI01 *flash[2];
+ GMappedFile *initrd_mapped_file;
/* Configuration options: */
uint64_t max_ram_below_4g;
--
2.20.1
