Messages in this thread Patch in this message | | | Date | Thu, 20 Nov 2008 16:44:40 +0900 | From | "Ryota OZAKI" <> | Subject | Re: [PATCH 0/4] ksm - dynamic page sharing driver for linux v2 |
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Hi Izik,
I've tried your patch set, but ksm doesn't work in my machine.
I compiled linux patched with the four patches and configured with KSM and KVM enabled. After boot with the linux, I run two VMs running linux using QEMU with a patch in your mail and started KSM scanner with your script, then the host linux caused panic with the following oops.
== BEGINNING of OOPS kernel BUG at arch/x86/mm/highmem_32.c:87! invalid opcode: 0000 [#1] SMP last sysfs file: /sys/class/net/vnet-ssh2/address Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: netconsole autofs4 nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack xt_tcpudp ipt_REJECT iptable_filter ip_tables x_tables loop kvm_intel kvm iTCO_wdt iTCO_vendor_support igb netxen_nic button ext3 jbd mbcache uhci_hcd ohci_hcd ehci_hcd usbcore [last unloaded: microcode]
Pid: 343, comm: kksmd Not tainted (2.6.28-rc5-linus-head-20081119-sparsemem #1) X7DWA EIP: 0060:[<c041eff9>] EFLAGS: 00010206 CPU: 6 EIP is at kmap_atomic_prot+0x7d/0xeb EAX: c0008d94 EBX: c1ff6240 ECX: 00000163 EDX: 7e000000 ESI: 00000154 EDI: 00000055 EBP: f5cdbf10 ESP: f5cdbef8 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 Process kksmd (pid: 343, ti=f5cda000 task=f617b140 task.ti=f5cda000) Stack: 7fa12163 fffff000 c204efbc f50479e8 9eb7e000 c08a34d0 f5cdbf18 c041f07a f5cdbf28 c048339c 00000000 f5c271e0 f5cdbf30 c04833bc f5cdbfb0 c0483b0d f5cdbf50 c0425845 00000000 00000064 00000009 c08a34d0 f5cdbfb0 c06384c1 Call Trace: [<c041f07a>] ? kmap_atomic+0x13/0x15 [<c048339c>] ? get_pte+0x50/0x63 [<c04833bc>] ? is_present_pte+0xd/0x1f [<c0483b0d>] ? ksm_scan_start+0x9a/0x7ac [<c0425845>] ? finish_task_switch+0x29/0xa4 [<c06384c1>] ? schedule+0x6bf/0x719 [<c041b3fc>] ? default_spin_lock_flags+0x8/0xc [<c043bffa>] ? finish_wait+0x49/0x4e [<c04845f4>] ? kthread_ksm_scan_thread+0x0/0xdc [<c048462e>] ? kthread_ksm_scan_thread+0x3a/0xdc [<c043bf31>] ? autoremove_wake_function+0x0/0x38 [<c043be3e>] ? kthread+0x40/0x66 [<c043bdfe>] ? kthread+0x0/0x66 [<c0404997>] ? kernel_thread_helper+0x7/0x10 Code: 86 00 00 00 64 a1 04 a0 82 c0 6b c0 0d 8d 3c 30 a1 78 b0 77 c0 8d 34 bd 00 00 00 00 89 45 ec a1 0c d0 84 c0 29 f0 83 38 00 74 04 <0f> 0b eb fe c1 ea 1a 8b 04 d5 80 32 8a c0 83 e0 fc 29 c3 c1 fb EIP: [<c041eff9>] kmap_atomic_prot+0x7d/0xeb SS:ESP 0068:f5cdbef8 Kernel panic - not syncing: Fatal exception == END of OOPS
I used a version of linux kernel from linus tree (commit e14c8bf863... at Mon Nov 17) with a configuration as the attached file and kvm-userspace (commit 0cf57d569f3... at Mon Nov 10). Other configurations are as follows:
Host: Fedora 8 Arch: i686 CPU: Intel(R) Xeon(R) CPU E5410 @ 2.33GHz Mem: 2 GB Guest: Fedora Core 7, linux-2.6.27 Cmd: qemu-system-x86_64 -kernel vmlinuz-2.6.27 -initrd initrd-2.6.27.img -append ro root=/dev/VolGroup00/LogVol00 kvm_paravirt=1 loglevel=4 rhgb quiet -hda -M pc -smp 1 -curses -clock dynticks -net nic,vlan=0,macaddr=00:00:00:1:11:0,model=virtio -net tap,vlan=0,ifname=vnet1,script=no -m 384
Note that if I disable HIGHMEM of the host kernel, ksm works well.
Any idea?
Thanks in advance, ozaki-r
2008/11/17 Izik Eidus <ieidus@redhat.com>: > (From v1 to v2 the main change is much more documentation) > > KSM is a linux driver that allows dynamicly sharing identical memory > pages between one or more processes. > > Unlike tradtional page sharing that is made at the allocation of the > memory, ksm do it dynamicly after the memory was created. > Memory is periodically scanned; identical pages are identified and > merged. > The sharing is unnoticeable by the process that use this memory. > (the shared pages are marked as readonly, and in case of write > do_wp_page() take care to create new copy of the page) > > This driver is very useful for KVM as in cases of runing multiple guests > operation system of the same type. > (For desktop work loads we have achived more than x2 memory overcommit > (more like x3)) > > This driver have found users other than KVM, for example CERN, > Fons Rademakers: > "on many-core machines we run one large detector simulation program per core. > These simulation programs are identical but run each in their own process and > need about 2 - 2.5 GB RAM. > We typically buy machines with 2GB RAM per core and so have a problem to run > one of these programs per core. > Of the 2 - 2.5 GB about 700MB is identical data in the form of magnetic field > maps, detector geometry, etc. > Currently people have been trying to start one program, initialize the geometry > and field maps and then fork it N times, to have the data shared. > With KSM this would be done automatically by the system so it sounded extremely > attractive when Andrea presented it." > > (We have are already started to test KSM on their systems...) > > KSM can run as kernel thread or as userspace application or both > > example for how to control the kernel thread: > > #include <stdio.h> > #include <stdlib.h> > #include <string.h> > #include <sys/types.h> > #include <sys/stat.h> > #include <sys/ioctl.h> > #include <fcntl.h> > #include <sys/mman.h> > #include <unistd.h> > #include "ksm.h" > > int main(int argc, char *argv[]) > { > int fd; > int used = 0; > int fd_start; > struct ksm_kthread_info info; > > > if (argc < 2) { > fprintf(stderr, > "usage: %s {start npages sleep | stop | info}\n", > argv[0]); > exit(1); > } > > fd = open("/dev/ksm", O_RDWR | O_TRUNC, (mode_t)0600); > if (fd == -1) { > fprintf(stderr, "could not open /dev/ksm\n"); > exit(1); > } > > if (!strncmp(argv[1], "start", strlen(argv[1]))) { > used = 1; > if (argc < 4) { > fprintf(stderr, > "usage: %s start npages_to_scan max_pages_to_merge sleep\n", > argv[0]); > exit(1); > } > info.pages_to_scan = atoi(argv[2]); > info.max_pages_to_merge = atoi(argv[3]); > info.sleep = atoi(argv[4]); > info.flags = ksm_control_flags_run; > > fd_start = ioctl(fd, KSM_START_STOP_KTHREAD, &info); > if (fd_start == -1) { > fprintf(stderr, "KSM_START_KTHREAD failed\n"); > exit(1); > } > printf("created scanner\n"); > } > > if (!strncmp(argv[1], "stop", strlen(argv[1]))) { > used = 1; > info.flags = 0; > fd_start = ioctl(fd, KSM_START_STOP_KTHREAD, &info); > printf("stopped scanner\n"); > } > > if (!strncmp(argv[1], "info", strlen(argv[1]))) { > used = 1; > ioctl(fd, KSM_GET_INFO_KTHREAD, &info); > printf("flags %d, pages_to_scan %d npages_merge %d, sleep_time %d\n", > info.flags, info.pages_to_scan, info.max_pages_to_merge, info.sleep); > } > > if (!used) > fprintf(stderr, "unknown command %s\n", argv[1]); > > return 0; > } > > example of how to register qemu to ksm (or any userspace application) > > diff --git a/qemu/vl.c b/qemu/vl.c > index 4721fdd..7785bf9 100644 > --- a/qemu/vl.c > +++ b/qemu/vl.c > @@ -21,6 +21,7 @@ > * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER > * DEALINGS IN > * THE SOFTWARE. > */ > +#include "ksm.h" > #include "hw/hw.h" > #include "hw/boards.h" > #include "hw/usb.h" > @@ -5799,6 +5800,37 @@ static void termsig_setup(void) > > #endif > > +int ksm_register_memory(void) > +{ > + int fd; > + int ksm_fd; > + int r = 1; > + struct ksm_memory_region ksm_region; > + > + fd = open("/dev/ksm", O_RDWR | O_TRUNC, (mode_t)0600); > + if (fd == -1) > + goto out; > + > + ksm_fd = ioctl(fd, KSM_CREATE_SHARED_MEMORY_AREA); > + if (ksm_fd == -1) > + goto out_free; > + > + ksm_region.npages = phys_ram_size / TARGET_PAGE_SIZE; > + ksm_region.addr = phys_ram_base; > + r = ioctl(ksm_fd, KSM_REGISTER_MEMORY_REGION, &ksm_region); > + if (r) > + goto out_free1; > + > + return r; > + > +out_free1: > + close(ksm_fd); > +out_free: > + close(fd); > +out: > + return r; > +} > + > int main(int argc, char **argv) > { > #ifdef CONFIG_GDBSTUB > @@ -6735,6 +6767,8 @@ int main(int argc, char **argv) > /* init the dynamic translator */ > cpu_exec_init_all(tb_size * 1024 * 1024); > > + ksm_register_memory(); > + > bdrv_init(); > > /* we always create the cdrom drive, even if no disk is there */ > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > [unhandled content-type:application/octet-stream] | |