linux/arch/x86
Takuya Yoshikawa 515a01279a KVM: pre-allocate one more dirty bitmap to avoid vmalloc()
Currently x86's kvm_vm_ioctl_get_dirty_log() needs to allocate a bitmap by
vmalloc() which will be used in the next logging and this has been causing
bad effect to VGA and live-migration: vmalloc() consumes extra systime,
triggers tlb flush, etc.

This patch resolves this issue by pre-allocating one more bitmap and switching
between two bitmaps during dirty logging.

Performance improvement:
  I measured performance for the case of VGA update by trace-cmd.
  The result was 1.5 times faster than the original one.

  In the case of live migration, the improvement ratio depends on the workload
  and the guest memory size. In general, the larger the memory size is the more
  benefits we get.

Note:
  This does not change other architectures's logic but the allocation size
  becomes twice. This will increase the actual memory consumption only when
  the new size changes the number of pages allocated by vmalloc().

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-01-12 11:28:46 +02:00
..
boot x86, setup: Use string copy operation to optimze copy in kernel compression 2010-10-07 21:23:09 -07:00
configs defconfig reduction 2010-08-14 22:26:53 +02:00
crypto crypto: ghash-intel - ghash-clmulni-intel_glue needs err.h 2010-12-15 19:44:08 +08:00
ia32 BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
include/asm KVM: x86: Add missing inline tag to kvm_read_and_reset_pf_reason 2011-01-12 11:23:27 +02:00
kernel KVM: Let host know whether the guest can handle async PF in non-userspace context. 2011-01-12 11:23:21 +02:00
kvm KVM: pre-allocate one more dirty bitmap to avoid vmalloc() 2011-01-12 11:28:46 +02:00
lguest lguest: populate initial_page_table 2010-12-16 17:03:15 +10:30
lib x86, mem: Optimize memmove for small size and unaligned cases 2010-09-24 18:57:11 -07:00
math-emu
mm x86: Use online node real index in calulate_tbl_offset() 2010-11-18 10:10:50 +01:00
oprofile Merge branch 'x86' of git://git.kernel.org/pub/scm/linux/kernel/git/rric/oprofile into perf/urgent 2010-10-25 19:17:32 +02:00
pci x86: avoid low BIOS area when allocating address space 2010-12-17 10:01:17 -08:00
platform x86: UV: Address interrupt/IO port operation conflict 2010-11-18 10:41:25 +01:00
power x86, tsc, sched: Recompute cyc2ns_offset's during resume from sleep states 2010-08-20 14:59:02 +02:00
tools
vdso Merge branches 'x86-cleanups-for-linus', 'x86-vmware-for-linus', 'x86-mtrr-for-linus', 'x86-apic-for-linus', 'x86-fpu-for-linus' and 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-08-06 16:22:59 -07:00
video
xen Merge branches 'x86-fixes-for-linus', 'perf-fixes-for-linus' and 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-12-08 06:40:59 -08:00
.gitignore
Kbuild x86: Add platform directory 2010-10-27 14:30:01 +02:00
Kconfig perf, x86: Fixup Kconfig deps 2010-11-26 15:00:58 +01:00
Kconfig.cpu Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-05-18 08:58:16 -07:00
Kconfig.debug Merge branch 'x86-irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-22 08:54:21 -07:00
Makefile Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-21 13:06:00 -07:00
Makefile_32.cpu jump label: Add work around to i386 gcc asm goto bug 2010-10-29 14:45:29 -04:00