From 3aaefce10351fecab348f5e06857f44cafc61a62 Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Wed, 6 Aug 2014 15:21:00 -0700 Subject: [PATCH 1/9] x86, platform, kconfig: move kvmconfig functionality to a helper The new mergeconfig helper makes it easier to add other partial configurations similar to kvmconfig. Architecture-independent portions of those partial configurations should go in kernel/configs/${name}.config, and architecture-dependent portions should go in arch/${arch}/configs/${name}.config. Based on a patch by Luis R. Rodriguez . Originally-Signed-off-by: Luis R. Rodriguez Modified to make the helper name more general than just virtualization, support architecture-dependent and architecture-independent partial configurations, move the helper and kvmconfig to scripts/kconfig/Makefile, and factor out more of the common file path. Signed-off-by: Josh Triplett --- arch/x86/Makefile | 7 ------- scripts/kconfig/Makefile | 14 ++++++++++++++ 2 files changed, 14 insertions(+), 7 deletions(-) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index c65fd9650467..fcc74b7aabb0 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -247,12 +247,6 @@ archclean: $(Q)$(MAKE) $(clean)=$(boot) $(Q)$(MAKE) $(clean)=arch/x86/tools -PHONY += kvmconfig -kvmconfig: - $(if $(wildcard $(objtree)/.config),, $(error You need an existing .config for this target)) - $(Q)$(CONFIG_SHELL) $(srctree)/scripts/kconfig/merge_config.sh -m -O $(objtree) $(objtree)/.config $(srctree)/arch/x86/configs/kvm_guest.config - $(Q)yes "" | $(MAKE) -f $(srctree)/Makefile oldconfig - define archhelp echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' echo ' install - Install kernel using' @@ -266,5 +260,4 @@ define archhelp echo ' bzdisk/fdimage*/isoimage also accept:' echo ' FDARGS="..." arguments for the booted kernel' echo ' FDINITRD=file initrd for the booted kernel' - echo ' kvmconfig - Enable additional options for guest kernel support' endef diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile index 9c4d2412fb72..8083b94b45ee 100644 --- a/scripts/kconfig/Makefile +++ b/scripts/kconfig/Makefile @@ -104,6 +104,19 @@ endif %_defconfig: $(obj)/conf $(Q)$< --defconfig=arch/$(SRCARCH)/configs/$@ $(Kconfig) +configfiles=$(wildcard $(srctree)/kernel/configs/$(1).config $(srctree)/arch/$(SRCARCH)/configs/$(1).config) + +define mergeconfig +$(if $(wildcard $(objtree)/.config),, $(error You need an existing .config for this target)) +$(if $(call configfiles,$(1)),, $(error No configuration exists for this target on this architecture)) +$(Q)$(CONFIG_SHELL) $(srctree)/scripts/kconfig/merge_config.sh -m -O $(objtree) $(objtree)/.config $(call configfiles,$(1)) +$(Q)yes "" | $(MAKE) -f $(srctree)/Makefile oldconfig +endef + +PHONY += kvmconfig +kvmconfig: + $(call mergeconfig,kvm_guest) + # Help text used by make help help: @echo ' config - Update current config utilising a line-oriented program' @@ -124,6 +137,7 @@ help: @echo ' randconfig - New config with random answer to all options' @echo ' listnewconfig - List new options' @echo ' olddefconfig - Same as silentoldconfig but sets new symbols to their default value' + @echo ' kvmconfig - Enable additional options for guest kernel support' # lxdialog stuff check-lxdialog := $(srctree)/$(src)/lxdialog/check-lxdialog.sh From 0da1d4a0b9516adb2acc4841e9f6da6618f47f4e Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Fri, 8 Aug 2014 16:25:47 -0700 Subject: [PATCH 2/9] x86: Add "make tinyconfig" to configure the tiniest possible kernel Since commit 5d2acfc7b974bbd3858b4dd3f2cdc6362dd8843a ("kconfig: make allnoconfig disable options behind EMBEDDED and EXPERT") in 3.15-rc1, "make allnoconfig" disables every possible config option. However, a few configuration options (CC_OPTIMIZE_FOR_SIZE, OPTIMIZE_INLINING) produce a smaller kernel when turned on, and a few choices exist (compression, highmem, allocator) for which a non-default option produces a smaller kernel. Add a "tinyconfig" option, which starts from allnoconfig and then sets these options to configure the tiniest possible kernel. This provides a better baseline for embedded systems or efforts to reduce kernel size. Signed-off-by: Josh Triplett --- arch/x86/configs/tiny.config | 1 + kernel/configs/tiny.config | 4 ++++ scripts/kconfig/Makefile | 5 +++++ 3 files changed, 10 insertions(+) create mode 100644 arch/x86/configs/tiny.config create mode 100644 kernel/configs/tiny.config diff --git a/arch/x86/configs/tiny.config b/arch/x86/configs/tiny.config new file mode 100644 index 000000000000..4e2ecfa23c15 --- /dev/null +++ b/arch/x86/configs/tiny.config @@ -0,0 +1 @@ +CONFIG_NOHIGHMEM=y diff --git a/kernel/configs/tiny.config b/kernel/configs/tiny.config new file mode 100644 index 000000000000..c2de56ab0fce --- /dev/null +++ b/kernel/configs/tiny.config @@ -0,0 +1,4 @@ +CONFIG_CC_OPTIMIZE_FOR_SIZE=y +CONFIG_KERNEL_XZ=y +CONFIG_OPTIMIZE_INLINING=y +CONFIG_SLOB=y diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile index 8083b94b45ee..ebf40f6edb4d 100644 --- a/scripts/kconfig/Makefile +++ b/scripts/kconfig/Makefile @@ -117,6 +117,10 @@ PHONY += kvmconfig kvmconfig: $(call mergeconfig,kvm_guest) +PHONY += tinyconfig +tinyconfig: allnoconfig + $(call mergeconfig,tiny) + # Help text used by make help help: @echo ' config - Update current config utilising a line-oriented program' @@ -138,6 +142,7 @@ help: @echo ' listnewconfig - List new options' @echo ' olddefconfig - Same as silentoldconfig but sets new symbols to their default value' @echo ' kvmconfig - Enable additional options for guest kernel support' + @echo ' tinyconfig - Configure the tiniest possible kernel' # lxdialog stuff check-lxdialog := $(srctree)/$(src)/lxdialog/check-lxdialog.sh From 9a1cb47112eff140659f04c261ca19fb1f002607 Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Mon, 10 Mar 2014 13:03:10 -0700 Subject: [PATCH 3/9] x86, boot: Use the usual -y -n mechanism for objects in vmlinux Switch VMLINUX_OBJS to vmlinux-objs-y, to eliminate Makefile conditionals in favor of vmlinux-objs-$(CONFIG_*) constructs. This does not change the generated code at all. Signed-off-by: Josh Triplett --- arch/x86/boot/compressed/Makefile | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 7a801a310e37..80709a98cc9c 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -26,18 +26,16 @@ LDFLAGS_vmlinux := -T hostprogs-y := mkpiggy HOST_EXTRACFLAGS += -I$(srctree)/tools/include -VMLINUX_OBJS = $(obj)/vmlinux.lds $(obj)/head_$(BITS).o $(obj)/misc.o \ +vmlinux-objs-y := $(obj)/vmlinux.lds $(obj)/head_$(BITS).o $(obj)/misc.o \ $(obj)/string.o $(obj)/cmdline.o $(obj)/early_serial_console.o \ $(obj)/piggy.o $(obj)/cpuflags.o $(obj)/aslr.o $(obj)/eboot.o: KBUILD_CFLAGS += -fshort-wchar -mno-red-zone -ifeq ($(CONFIG_EFI_STUB), y) - VMLINUX_OBJS += $(obj)/eboot.o $(obj)/efi_stub_$(BITS).o \ - $(objtree)/drivers/firmware/efi/libstub/lib.a -endif +vmlinux-objs-$(CONFIG_EFI_STUB) += $(obj)/eboot.o $(obj)/efi_stub_$(BITS).o \ + $(objtree)/drivers/firmware/efi/libstub/lib.a -$(obj)/vmlinux: $(VMLINUX_OBJS) FORCE +$(obj)/vmlinux: $(vmlinux-objs-y) FORCE $(call if_changed,ld) @: @@ -45,7 +43,7 @@ OBJCOPYFLAGS_vmlinux.bin := -R .comment -S $(obj)/vmlinux.bin: vmlinux FORCE $(call if_changed,objcopy) -targets += $(patsubst $(obj)/%,%,$(VMLINUX_OBJS)) vmlinux.bin.all vmlinux.relocs +targets += $(patsubst $(obj)/%,%,$(vmlinux-objs-y)) vmlinux.bin.all vmlinux.relocs CMD_RELOCS = arch/x86/tools/relocs quiet_cmd_relocs = RELOCS $@ From 9e6abd2a98ca599e0efb8c46acc17f17dc1a6fe9 Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Mon, 10 Mar 2014 13:11:26 -0700 Subject: [PATCH 4/9] x86, boot: Don't compile aslr.c when !CONFIG_RANDOMIZE_BASE All the code in aslr.c gets compiled out if !CONFIG_RANDOMIZE_BASE, but aslr.o itself still gets compiled in. Eliminate it from the compile entirely in that case. This does not change the generated code at all, in either case. Signed-off-by: Josh Triplett --- arch/x86/boot/compressed/Makefile | 4 +++- arch/x86/boot/compressed/aslr.c | 3 --- 2 files changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 80709a98cc9c..3b9b00c68fd8 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -28,7 +28,9 @@ HOST_EXTRACFLAGS += -I$(srctree)/tools/include vmlinux-objs-y := $(obj)/vmlinux.lds $(obj)/head_$(BITS).o $(obj)/misc.o \ $(obj)/string.o $(obj)/cmdline.o $(obj)/early_serial_console.o \ - $(obj)/piggy.o $(obj)/cpuflags.o $(obj)/aslr.o + $(obj)/piggy.o $(obj)/cpuflags.o + +vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/aslr.o $(obj)/eboot.o: KBUILD_CFLAGS += -fshort-wchar -mno-red-zone diff --git a/arch/x86/boot/compressed/aslr.c b/arch/x86/boot/compressed/aslr.c index fc6091abedb7..913c999b0045 100644 --- a/arch/x86/boot/compressed/aslr.c +++ b/arch/x86/boot/compressed/aslr.c @@ -1,6 +1,5 @@ #include "misc.h" -#ifdef CONFIG_RANDOMIZE_BASE #include #include #include @@ -320,5 +319,3 @@ unsigned char *choose_kernel_location(unsigned char *input, out: return (unsigned char *)choice; } - -#endif /* CONFIG_RANDOMIZE_BASE */ From 3afed06a355b5525d9a87bcb76567ef2e2e7b3a2 Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Mon, 10 Mar 2014 13:26:10 -0700 Subject: [PATCH 5/9] x86, boot: Don't compile early_serial_console.c when !CONFIG_EARLY_PRINTK All the code in early_serial_console.c gets compiled out if !CONFIG_EARLY_PRINTK, but early_serial_console.o itself still gets compiled in. Eliminate it from the compile entirely in that case. This does not change the generated code at all, in either case. Signed-off-by: Josh Triplett --- arch/x86/boot/compressed/Makefile | 3 ++- arch/x86/boot/compressed/early_serial_console.c | 4 ---- 2 files changed, 2 insertions(+), 5 deletions(-) diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 3b9b00c68fd8..20db5b3609de 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -27,9 +27,10 @@ hostprogs-y := mkpiggy HOST_EXTRACFLAGS += -I$(srctree)/tools/include vmlinux-objs-y := $(obj)/vmlinux.lds $(obj)/head_$(BITS).o $(obj)/misc.o \ - $(obj)/string.o $(obj)/cmdline.o $(obj)/early_serial_console.o \ + $(obj)/string.o $(obj)/cmdline.o \ $(obj)/piggy.o $(obj)/cpuflags.o +vmlinux-objs-$(CONFIG_EARLY_PRINTK) += $(obj)/early_serial_console.o vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/aslr.o $(obj)/eboot.o: KBUILD_CFLAGS += -fshort-wchar -mno-red-zone diff --git a/arch/x86/boot/compressed/early_serial_console.c b/arch/x86/boot/compressed/early_serial_console.c index d3d003cb5481..261e81fb9582 100644 --- a/arch/x86/boot/compressed/early_serial_console.c +++ b/arch/x86/boot/compressed/early_serial_console.c @@ -1,9 +1,5 @@ #include "misc.h" -#ifdef CONFIG_EARLY_PRINTK - int early_serial_base; #include "../early_serial_console.c" - -#endif From 39f838e06f46576694d425ac30fe8ff1e214fc0b Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Wed, 30 Oct 2013 14:21:53 +0000 Subject: [PATCH 6/9] x86: Drop support for /proc files when !CONFIG_PROC_FS arch/x86/kernel/cpu/proc.c only exists to support files in /proc; omit that file when compiling without CONFIG_PROC_FS. Saves 645 additional bytes on 32-bit x86 when !CONFIG_PROC_FS: add/remove: 0/5 grow/shrink: 0/0 up/down: 0/-645 (-645) function old new delta c_stop 1 - -1 c_next 11 - -11 cpuinfo_op 16 - -16 c_start 24 - -24 show_cpuinfo 593 - -593 Signed-off-by: Josh Triplett --- arch/x86/kernel/cpu/Makefile | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile index 7fd54f09b011..64038d842c57 100644 --- a/arch/x86/kernel/cpu/Makefile +++ b/arch/x86/kernel/cpu/Makefile @@ -13,10 +13,12 @@ nostackp := $(call cc-option, -fno-stack-protector) CFLAGS_common.o := $(nostackp) obj-y := intel_cacheinfo.o scattered.o topology.o -obj-y += proc.o capflags.o powerflags.o common.o +obj-y += capflags.o powerflags.o common.o obj-y += rdrand.o obj-y += match.o +obj-$(CONFIG_PROC_FS) += proc.o + obj-$(CONFIG_X86_32) += bugs.o obj-$(CONFIG_X86_64) += bugs_64.o From 9def39be4e960917fcb80514ff23651f9ec97193 Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Wed, 30 Oct 2013 08:09:45 -0700 Subject: [PATCH 7/9] x86: Support compiling out human-friendly processor feature names The table mapping CPUID bits to human-readable strings takes up a non-trivial amount of space, and only exists to support /proc/cpuinfo and a couple of kernel messages. Since programs depend on the format of /proc/cpuinfo, force inclusion of the table when building with /proc support; otherwise, support omitting that table to save space, in which case the kernel messages will print features numerically instead. In addition to saving 1408 bytes out of vmlinux, this also saves 1373 bytes out of the uncompressed setup code, which contributes directly to the size of bzImage. Signed-off-by: Josh Triplett --- arch/x86/Kconfig | 12 ++++++ arch/x86/boot/Makefile | 7 +++- arch/x86/boot/cpu.c | 68 +++++++++++++++++++------------ arch/x86/include/asm/cpufeature.h | 7 ++++ arch/x86/kernel/cpu/Makefile | 5 ++- arch/x86/kernel/cpu/common.c | 4 +- 6 files changed, 71 insertions(+), 32 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 5d0bf1aa9dcb..a11f27c4266a 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -136,6 +136,7 @@ config X86 select HAVE_ACPI_APEI if ACPI select HAVE_ACPI_APEI_NMI if ACPI select ACPI_LEGACY_TABLES_LOOKUP if ACPI + select X86_FEATURE_NAMES if PROC_FS config INSTRUCTION_DECODER def_bool y @@ -313,6 +314,17 @@ config SMP If you don't know what to do here, say N. +config X86_FEATURE_NAMES + bool "Processor feature human-readable names" if EMBEDDED + default y + ---help--- + This option compiles in a table of x86 feature bits and corresponding + names. This is required to support /proc/cpuinfo and a few kernel + messages. You can disable this to save space, at the expense of + making those few kernel messages show numeric feature bits instead. + + If in doubt, say Y. + config X86_X2APIC bool "Support x2apic" depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index dbe8dd2fe247..5b016e2498f3 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -35,19 +35,22 @@ setup-y += video-vesa.o setup-y += video-bios.o targets += $(setup-y) -hostprogs-y := mkcpustr tools/build +hostprogs-y := tools/build +hostprogs-$(CONFIG_X86_FEATURE_NAMES) += mkcpustr HOST_EXTRACFLAGS += -I$(srctree)/tools/include \ -include include/generated/autoconf.h \ -D__EXPORTED_HEADERS__ +ifdef CONFIG_X86_FEATURE_NAMES $(obj)/cpu.o: $(obj)/cpustr.h quiet_cmd_cpustr = CPUSTR $@ cmd_cpustr = $(obj)/mkcpustr > $@ -targets += cpustr.h +targets += cpustr.h $(obj)/cpustr.h: $(obj)/mkcpustr FORCE $(call if_changed,cpustr) +endif # --------------------------------------------------------------------------- diff --git a/arch/x86/boot/cpu.c b/arch/x86/boot/cpu.c index 6ec6bb6e9957..29207f69ae8c 100644 --- a/arch/x86/boot/cpu.c +++ b/arch/x86/boot/cpu.c @@ -16,7 +16,9 @@ */ #include "boot.h" +#ifdef CONFIG_X86_FEATURE_NAMES #include "cpustr.h" +#endif static char *cpu_name(int level) { @@ -32,11 +34,48 @@ static char *cpu_name(int level) } } +static void show_cap_strs(u32 *err_flags) +{ + int i, j; +#ifdef CONFIG_X86_FEATURE_NAMES + const unsigned char *msg_strs = (const unsigned char *)x86_cap_strs; + for (i = 0; i < NCAPINTS; i++) { + u32 e = err_flags[i]; + for (j = 0; j < 32; j++) { + if (msg_strs[0] < i || + (msg_strs[0] == i && msg_strs[1] < j)) { + /* Skip to the next string */ + msg_strs += 2; + while (*msg_strs++) + ; + } + if (e & 1) { + if (msg_strs[0] == i && + msg_strs[1] == j && + msg_strs[2]) + printf("%s ", msg_strs+2); + else + printf("%d:%d ", i, j); + } + e >>= 1; + } + } +#else + for (i = 0; i < NCAPINTS; i++) { + u32 e = err_flags[i]; + for (j = 0; j < 32; j++) { + if (e & 1) + printf("%d:%d ", i, j); + e >>= 1; + } + } +#endif +} + int validate_cpu(void) { u32 *err_flags; int cpu_level, req_level; - const unsigned char *msg_strs; check_cpu(&cpu_level, &req_level, &err_flags); @@ -49,34 +88,9 @@ int validate_cpu(void) } if (err_flags) { - int i, j; puts("This kernel requires the following features " "not present on the CPU:\n"); - - msg_strs = (const unsigned char *)x86_cap_strs; - - for (i = 0; i < NCAPINTS; i++) { - u32 e = err_flags[i]; - - for (j = 0; j < 32; j++) { - if (msg_strs[0] < i || - (msg_strs[0] == i && msg_strs[1] < j)) { - /* Skip to the next string */ - msg_strs += 2; - while (*msg_strs++) - ; - } - if (e & 1) { - if (msg_strs[0] == i && - msg_strs[1] == j && - msg_strs[2]) - printf("%s ", msg_strs+2); - else - printf("%d:%d ", i, j); - } - e >>= 1; - } - } + show_cap_strs(err_flags); putchar('\n'); return -1; } else { diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index bb9b258d60e7..516903b98e06 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -250,8 +250,15 @@ #include #include +#ifdef CONFIG_X86_FEATURE_NAMES extern const char * const x86_cap_flags[NCAPINTS*32]; extern const char * const x86_power_flags[32]; +#define X86_CAP_FMT "%s" +#define x86_cap_flag(flag) x86_cap_flags[flag] +#else +#define X86_CAP_FMT "%d:%d" +#define x86_cap_flag(flag) ((flag) >> 5), ((flag) & 31) +#endif /* * In order to save room, we index into this array by doing diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile index 64038d842c57..77dcab277710 100644 --- a/arch/x86/kernel/cpu/Makefile +++ b/arch/x86/kernel/cpu/Makefile @@ -13,11 +13,12 @@ nostackp := $(call cc-option, -fno-stack-protector) CFLAGS_common.o := $(nostackp) obj-y := intel_cacheinfo.o scattered.o topology.o -obj-y += capflags.o powerflags.o common.o +obj-y += common.o obj-y += rdrand.o obj-y += match.o obj-$(CONFIG_PROC_FS) += proc.o +obj-$(CONFIG_X86_FEATURE_NAMES) += capflags.o powerflags.o obj-$(CONFIG_X86_32) += bugs.o obj-$(CONFIG_X86_64) += bugs_64.o @@ -50,6 +51,7 @@ obj-$(CONFIG_X86_LOCAL_APIC) += perfctr-watchdog.o perf_event_amd_ibs.o obj-$(CONFIG_HYPERVISOR_GUEST) += vmware.o hypervisor.o mshyperv.o +ifdef CONFIG_X86_FEATURE_NAMES quiet_cmd_mkcapflags = MKCAP $@ cmd_mkcapflags = $(CONFIG_SHELL) $(srctree)/$(src)/mkcapflags.sh $< $@ @@ -58,3 +60,4 @@ cpufeature = $(src)/../../include/asm/cpufeature.h targets += capflags.c $(obj)/capflags.c: $(cpufeature) $(src)/mkcapflags.sh FORCE $(call if_changed,mkcapflags) +endif diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index e4ab2b42bd6f..c649f236e288 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -346,8 +346,8 @@ static void filter_cpuid_features(struct cpuinfo_x86 *c, bool warn) continue; printk(KERN_WARNING - "CPU: CPU feature %s disabled, no CPUID level 0x%x\n", - x86_cap_flags[df->feature], df->level); + "CPU: CPU feature " X86_CAP_FMT " disabled, no CPUID level 0x%x\n", + x86_cap_flag(df->feature), df->level); } } From d3ac21cacc24790eb45d735769f35753f5b56ceb Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Sun, 17 Aug 2014 19:41:09 -0500 Subject: [PATCH 8/9] mm: Support compiling out madvise and fadvise Many embedded systems will not need these syscalls, and omitting them saves space. Add a new EXPERT config option CONFIG_ADVISE_SYSCALLS (default y) to support compiling them out. bloat-o-meter: add/remove: 0/3 grow/shrink: 0/0 up/down: 0/-2250 (-2250) function old new delta sys_fadvise64 57 - -57 sys_fadvise64_64 691 - -691 sys_madvise 1502 - -1502 Signed-off-by: Josh Triplett --- init/Kconfig | 10 ++++++++++ kernel/sys_ni.c | 3 +++ mm/Makefile | 7 +++++-- 3 files changed, 18 insertions(+), 2 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index e84c6423a2e5..782a65bf76ea 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1537,6 +1537,16 @@ config AIO by some high performance threaded applications. Disabling this option saves about 7k. +config ADVISE_SYSCALLS + bool "Enable madvise/fadvise syscalls" if EXPERT + default y + help + This option enables the madvise and fadvise syscalls, used by + applications to advise the kernel about their future memory or file + usage, improving performance. If building an embedded system where no + applications use these syscalls, you can disable this option to save + space. + config PCI_QUIRKS default y bool "Enable PCI quirk workarounds" if EXPERT diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index 391d4ddb6f4b..d4709d481053 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -156,6 +156,9 @@ cond_syscall(sys_process_vm_writev); cond_syscall(compat_sys_process_vm_readv); cond_syscall(compat_sys_process_vm_writev); cond_syscall(sys_uselib); +cond_syscall(sys_fadvise64); +cond_syscall(sys_fadvise64_64); +cond_syscall(sys_madvise); /* arch-specific weak syscall entries */ cond_syscall(sys_pciconfig_read); diff --git a/mm/Makefile b/mm/Makefile index 632ae77e6070..fe7a053c0f45 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -3,7 +3,7 @@ # mmu-y := nommu.o -mmu-$(CONFIG_MMU) := fremap.o gup.o highmem.o madvise.o memory.o mincore.o \ +mmu-$(CONFIG_MMU) := fremap.o gup.o highmem.o memory.o mincore.o \ mlock.o mmap.o mprotect.o mremap.o msync.o rmap.o \ vmalloc.o pagewalk.o pgtable-generic.o @@ -11,7 +11,7 @@ ifdef CONFIG_CROSS_MEMORY_ATTACH mmu-$(CONFIG_MMU) += process_vm_access.o endif -obj-y := filemap.o mempool.o oom_kill.o fadvise.o \ +obj-y := filemap.o mempool.o oom_kill.o \ maccess.o page_alloc.o page-writeback.o \ readahead.o swap.o truncate.o vmscan.o shmem.o \ util.o mmzone.o vmstat.o backing-dev.o \ @@ -28,6 +28,9 @@ else obj-y += bootmem.o endif +ifdef CONFIG_MMU + obj-$(CONFIG_ADVISE_SYSCALLS) += fadvise.o madvise.o +endif obj-$(CONFIG_HAVE_MEMBLOCK) += memblock.o obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o From b25c2ff547530f63d71fc67048543ae54b434476 Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Sun, 17 Aug 2014 19:45:46 -0500 Subject: [PATCH 9/9] bloat-o-meter: Ignore syscall aliases SyS_ and compat_SyS_ This avoids double-counting size changes in syscall implementations. Signed-off-by: Josh Triplett --- scripts/bloat-o-meter | 2 ++ 1 file changed, 2 insertions(+) diff --git a/scripts/bloat-o-meter b/scripts/bloat-o-meter index 549d0ab8c662..23e78dcd12bf 100755 --- a/scripts/bloat-o-meter +++ b/scripts/bloat-o-meter @@ -20,6 +20,8 @@ def getsizes(file): if type in "tTdDbBrR": # strip generated symbols if name.startswith("__mod_"): continue + if name.startswith("SyS_"): continue + if name.startswith("compat_SyS_"): continue if name == "linux_banner": continue # statics and some other optimizations adds random .NUMBER name = re.sub(r'\.[0-9]+', '', name)