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Commit d3ac21ca authored by Josh Triplett's avatar Josh Triplett
Browse files

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: default avatarJosh Triplett <josh@joshtriplett.org>
parent 7d1311b9

init/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -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

kernel/sys_ni.c

+3 −0
Original line number Diff line number Diff line
@@ -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);

mm/Makefile

+5 −2
Original line number Diff line number Diff line
@@ -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