Xunlei Pang 66aad4fdf2 x86/mm: Add support for gbpages to kernel_ident_mapping_init() ... Kernel identity mappings on x86-64 kernels are created in two ways: by the early x86 boot code, or by kernel_ident_mapping_init(). Native kernels (which is the dominant usecase) use the former, but the kexec and the hibernation code uses kernel_ident_mapping_init(). There's a subtle difference between these two ways of how identity mappings are created, the current kernel_ident_mapping_init() code creates identity mappings always using 2MB page(PMD level) - while the native kernel boot path also utilizes gbpages where available. This difference is suboptimal both for performance and for memory usage: kernel_ident_mapping_init() needs to allocate pages for the page tables when creating the new identity mappings. This patch adds 1GB page(PUD level) support to kernel_ident_mapping_init() to address these concerns. The primary advantage would be better TLB coverage/performance, because we'd utilize 1GB TLBs instead of 2MB ones. It is also useful for machines with large number of memory to save paging structure allocations(around 4MB/TB using 2MB page) when setting identity mappings for all the memory, after using 1GB page it will consume only 8KB/TB. ( Note that this change alone does not activate gbpages in kexec, we are doing that in a separate patch. ) Signed-off-by: Xunlei Pang <xlpang@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Young <dyoung@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yinghai Lu <yinghai@kernel.org> Cc: akpm@linux-foundation.org Cc: kexec@lists.infradead.org Link: http://lkml.kernel.org/r/1493862171-8799-1-git-send-email-xlpang@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>		2017-05-08 08:28:40 +02:00
..
compressed	x86/mm: Add support for gbpages to kernel_ident_mapping_init()	2017-05-08 08:28:40 +02:00
tools
.gitignore
a20.c
apm.c
bioscall.S
bitops.h	x86, asm: use bool for bitops and other assembly outputs	2016-06-08 12:41:20 -07:00
boot.h	x86/boot: Fix BSS corruption/overwrite bug in early x86 kernel startup	2017-04-20 10:05:23 +02:00
cmdline.c
code16gcc.h
copy.S
cpu.c	Revert "x86/boot: Fail the boot if !M486 and CPUID is missing"	2016-12-19 11:54:20 +01:00
cpucheck.c	x86/boot: Detect 5-level paging support	2017-04-04 08:22:33 +02:00
cpuflags.c	x86/boot: Detect 5-level paging support	2017-04-04 08:22:33 +02:00
cpuflags.h	x86/mm: Disallow running with 32-bit PTEs to work around erratum	2016-07-13 09:43:25 +02:00
ctype.h
early_serial_console.c	x86/boot: Add missing file header comments	2016-05-10 10:12:03 +02:00
edd.c
header.S	x86/boot/e820: Remove assembly guard from asm/e820/types.h	2017-01-28 09:31:15 +01:00
install.sh
main.c
Makefile	x86/boot/build: Remove always empty $(USERINCLUDE)	2016-11-07 07:30:01 +01:00
memory.c	x86/boot/e820: Separate the E820 ABI structures from the in-kernel structures	2017-01-29 13:39:32 +01:00
mkcpustr.c
mtools.conf.in
pm.c
pmjump.S
printf.c
regs.c
setup.ld
string.c	Merge branch 'linus' into x86/boot, to pick up fixes	2017-01-28 09:30:11 +01:00
string.h	x86/boot: Add missing declaration of string functions	2017-01-09 11:53:05 +01:00
tty.c
version.c
vesa.h
video-bios.c
video-mode.c
video-vesa.c
video-vga.c
video.c
video.h