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hw/i386/pc: Map into memory the initrd 

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 <pbonzini@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20190724143105.307042-4-sgarzare@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Stefano Garzarella 2019-07-24 16:31:05 +02:00 committed by Paolo Bonzini
parent 816b9fe450
commit e502fe96ac
2 changed files with 14 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
hw/i386/pc.c
View File

@ -1244,17 +1244,21 @@ 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."
@ -1381,6 +1385,7 @@ static void load_linux(PCMachineState *pcms,
/* load initrd */
if (initrd_filename) {
GMappedFile *mapped_file;
gsize initrd_size;
gchar *initrd_data;
GError *gerr = NULL;
@ -1390,12 +1395,16 @@ 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",

1
include/hw/i386/pc.h
View File

@ -41,6 +41,7 @@ struct PCMachineState {
FWCfgState *fw_cfg;
qemu_irq *gsi;
PFlashCFI01 *flash[2];
GMappedFile *initrd_mapped_file;
/* Configuration options: */
uint64_t max_ram_below_4g;