Commit-ID: e5008abe929c160d36e44b8c2b644d4330d2e389 Gitweb: http://git.kernel.org/tip/e5008abe929c160d36e44b8c2b644d4330d2e389 Author: Luis R. Rodriguez <[email protected]> AuthorDate: Wed, 4 Mar 2015 17:24:12 -0800 Committer: Ingo Molnar <[email protected]> CommitDate: Thu, 5 Mar 2015 08:02:12 +0100
x86/mm: Simplify enabling direct_gbpages direct_gbpages can be force enabled as an early parameter but not really have taken effect when DEBUG_PAGEALLOC or KMEMCHECK is enabled. You can also enable direct_gbpages right now if you have an x86_64 architecture but your CPU doesn't really have support for this feature. In both cases PG_LEVEL_1G won't actually be enabled but direct_gbpages is used in other areas under the assumptions that PG_LEVEL_1G was set. Fix this by putting together all requirements which make this feature sensible to enable under, and only enable both finally flipping on PG_LEVEL_1G and leaving PG_LEVEL_1G set when this is true. We only enable this feature then to be possible on sensible builds defined by the new ENABLE_DIRECT_GBPAGES. If the CPU has support for it you can either enable this by using the DIRECT_GBPAGES option or using the early kernel parameter. If a platform had support for this you can always force disable it as well. Signed-off-by: Luis R. Rodriguez <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Dave Hansen <[email protected]> Cc: David Vrabel <[email protected]> Cc: Dexuan Cui <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: [email protected] Cc: Jan Beulich <[email protected]> Cc: Joonsoo Kim <[email protected]> Cc: Juergen Gross <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Pavel Machek <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Tony Lindgren <[email protected]> Cc: Toshi Kani <[email protected]> Cc: Vlastimil Babka <[email protected]> Cc: Xishi Qiu <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/Kconfig | 18 +++++++++++++----- arch/x86/mm/init.c | 17 +++++++++-------- arch/x86/mm/pageattr.c | 2 -- 3 files changed, 22 insertions(+), 15 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index c2fb8a8..4d06e1c 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1299,14 +1299,22 @@ config ARCH_DMA_ADDR_T_64BIT def_bool y depends on X86_64 || HIGHMEM64G +config ENABLE_DIRECT_GBPAGES + def_bool y + depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK + config DIRECT_GBPAGES bool "Enable 1GB pages for kernel pagetables" if EXPERT default y - depends on X86_64 - ---help--- - Allow the kernel linear mapping to use 1GB pages on CPUs that - support it. This can improve the kernel's performance a tiny bit by - reducing TLB pressure. If in doubt, say "Y". + depends on ENABLE_DIRECT_GBPAGES + ---help--- + Enable by default the kernel linear mapping to use 1GB pages on CPUs + that support it. This can improve the kernel's performance a tiny bit + by reducing TLB pressure. If in doubt, say "Y". If you've disabled + option but your platform is capable of handling support for this + you can use the gbpages kernel parameter. Likewise if you've enabled + this but you'd like to force disable this option you can use the + nogbpages kernel parameter. # Common NUMA Features config NUMA diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 74f2b37..2ce2c8e 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -131,16 +131,21 @@ void __init early_alloc_pgt_buf(void) int after_bootmem; +static int page_size_mask; + int direct_gbpages = IS_ENABLED(CONFIG_DIRECT_GBPAGES); static void __init init_gbpages(void) { -#ifdef CONFIG_X86_64 - if (direct_gbpages && cpu_has_gbpages) + if (!IS_ENABLED(CONFIG_ENABLE_DIRECT_GBPAGES)) { + direct_gbpages = 0; + return; + } + if (direct_gbpages && cpu_has_gbpages) { printk(KERN_INFO "Using GB pages for direct mapping\n"); - else + page_size_mask |= 1 << PG_LEVEL_1G; + } else direct_gbpages = 0; -#endif } struct map_range { @@ -149,8 +154,6 @@ struct map_range { unsigned page_size_mask; }; -static int page_size_mask; - static void __init probe_page_size_mask(void) { init_gbpages(); @@ -161,8 +164,6 @@ static void __init probe_page_size_mask(void) * This will simplify cpa(), which otherwise needs to support splitting * large pages into small in interrupt context, etc. */ - if (direct_gbpages) - page_size_mask |= 1 << PG_LEVEL_1G; if (cpu_has_pse) page_size_mask |= 1 << PG_LEVEL_2M; #endif diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 81e8282..89af288 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -81,11 +81,9 @@ void arch_report_meminfo(struct seq_file *m) seq_printf(m, "DirectMap4M: %8lu kB\n", direct_pages_count[PG_LEVEL_2M] << 12); #endif -#ifdef CONFIG_X86_64 if (direct_gbpages) seq_printf(m, "DirectMap1G: %8lu kB\n", direct_pages_count[PG_LEVEL_1G] << 20); -#endif } #else static inline void split_page_count(int level) { } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
