linux/arch
Takuya Yoshikawa 95d4c16ce7 KVM: Optimize dirty logging by rmap_write_protect()
Currently, write protecting a slot needs to walk all the shadow pages
and checks ones which have a pte mapping a page in it.

The walk is overly heavy when dirty pages in that slot are not so many
and checking the shadow pages would result in unwanted cache pollution.

To mitigate this problem, we use rmap_write_protect() and check only
the sptes which can be reached from gfns marked in the dirty bitmap
when the number of dirty pages are less than that of shadow pages.

This criterion is reasonable in its meaning and worked well in our test:
write protection became some times faster than before when the ratio of
dirty pages are low and was not worse even when the ratio was near the
criterion.

Note that the locking for this write protection becomes fine grained.
The reason why this is safe is descripted in the comments.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-27 11:17:20 +02:00
..
alpha Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
arm Merge branch 'rmobile-fixes-for-linus' of git://github.com/pmundt/linux-sh 2011-12-20 11:32:18 -08:00
avr32 Merge git://git.infradead.org/mtd-2.6 2011-11-07 09:11:16 -08:00
blackfin blackfin: Fixup export.h includes 2011-11-14 17:15:23 +08:00
cris net: Fix references to deleted NET_ETHERNET Kconfig setting. 2011-11-09 19:26:53 -05:00
frv kgdb: follow rename pack_hex_byte() to hex_byte_pack() 2011-10-31 17:30:56 -07:00
h8300 Merge branch 'gpio/next' of git://git.secretlab.ca/git/linux-2.6 2011-10-29 07:27:45 -07:00
hexagon Hexagon: Add basic stacktrace functionality for Hexagon architecture. 2011-11-01 07:34:21 -07:00
ia64 Merge branch 'upstream/xen-settime' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen 2011-11-06 20:15:05 -08:00
m32r Merge branch 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2011-11-06 18:54:53 -08:00
m68k m68k: Wire up process_vm_{read,write}v 2011-12-06 20:37:58 +01:00
microblaze microblaze: bury asm/namei.h 2011-11-21 16:48:28 -05:00
mips Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2011-12-05 16:54:00 -08:00
mn10300 kgdb: follow rename pack_hex_byte() to hex_byte_pack() 2011-10-31 17:30:56 -07:00
openrisc Merge branch 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2011-11-06 18:54:53 -08:00
parisc parisc: Add export.h to files needing EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:31:00 -04:00
powerpc KVM: PPC: e500: include linux/export.h 2011-12-26 13:28:03 +02:00
s390 oprofile: Fix uninitialized memory access when writing to writing to oprofilefs 2011-12-19 17:18:43 +01:00
score score: drop unused Kconfig symbols 2011-10-31 23:39:51 +01:00
sh sh: fix build warning in board-sh7757lcr 2011-11-18 16:45:50 +09:00
sparc sparc64: Fix MSIQ HV call ordering in pci_sun4v_msiq_build_irq(). 2011-12-22 13:46:53 -08:00
tile arch/tile: use new generic {enable,disable}_percpu_irq() routines 2011-12-03 15:31:49 -05:00
um Merge branch 'for-linus' of git://github.com/richardweinberger/linux 2011-11-02 09:45:39 -07:00
unicore32 unicore32, exec: remove redundant set_fs(USER_DS) 2011-11-16 10:50:09 +08:00
x86 KVM: Optimize dirty logging by rmap_write_protect() 2011-12-27 11:17:20 +02:00
xtensa Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2011-10-26 17:15:03 +02:00
.gitignore
Kconfig