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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 <josh@joshtriplett.org>
This commit is contained in:
Josh Triplett 2014-08-17 19:41:09 -05:00
parent 7d1311b93e
commit d3ac21cacc
3 changed files with 18 additions and 2 deletions
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10
init/Kconfig
View File

@ -1537,6 +1537,16 @@ config AIO
by some high performance threaded applications. Disabling by some high performance threaded applications. Disabling
this option saves about 7k. 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 config PCI_QUIRKS
default y default y
bool "Enable PCI quirk workarounds" if EXPERT bool "Enable PCI quirk workarounds" if EXPERT

3
kernel/sys_ni.c
View File

@ -156,6 +156,9 @@ cond_syscall(sys_process_vm_writev);
cond_syscall(compat_sys_process_vm_readv); cond_syscall(compat_sys_process_vm_readv);
cond_syscall(compat_sys_process_vm_writev); cond_syscall(compat_sys_process_vm_writev);
cond_syscall(sys_uselib); cond_syscall(sys_uselib);
cond_syscall(sys_fadvise64);
cond_syscall(sys_fadvise64_64);
cond_syscall(sys_madvise);
/* arch-specific weak syscall entries */ /* arch-specific weak syscall entries */
cond_syscall(sys_pciconfig_read); cond_syscall(sys_pciconfig_read);

7
mm/Makefile
View File

@ -3,7 +3,7 @@
# #
mmu-y := nommu.o 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 \ mlock.o mmap.o mprotect.o mremap.o msync.o rmap.o \
vmalloc.o pagewalk.o pgtable-generic.o vmalloc.o pagewalk.o pgtable-generic.o
@ -11,7 +11,7 @@ ifdef CONFIG_CROSS_MEMORY_ATTACH
mmu-$(CONFIG_MMU) += process_vm_access.o mmu-$(CONFIG_MMU) += process_vm_access.o
endif 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 \ maccess.o page_alloc.o page-writeback.o \
readahead.o swap.o truncate.o vmscan.o shmem.o \ readahead.o swap.o truncate.o vmscan.o shmem.o \
util.o mmzone.o vmstat.o backing-dev.o \ util.o mmzone.o vmstat.o backing-dev.o \
@ -28,6 +28,9 @@ else
obj-y += bootmem.o obj-y += bootmem.o
endif endif
ifdef CONFIG_MMU
obj-$(CONFIG_ADVISE_SYSCALLS) += fadvise.o madvise.o
endif
obj-$(CONFIG_HAVE_MEMBLOCK) += memblock.o obj-$(CONFIG_HAVE_MEMBLOCK) += memblock.o
obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o