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Message-ID: <20140925183254.GA9575@cloud> Date: Thu, 25 Sep 2014 11:32:54 -0700 From: josh@...htriplett.org To: Andrew Morton <akpm@...ux-foundation.org>, "H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org, linux-api@...r.kernel.org, linux-mm@...ck.org Subject: [PATCHv2] 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@...htriplett.org> --- v2: Don't make fadvise depend on CONFIG_MMU. init/Kconfig | 10 ++++++++++ kernel/sys_ni.c | 3 +++ mm/Makefile | 8 ++++++-- 3 files changed, 19 insertions(+), 2 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index e84c642..782a65b 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 391d4dd..d4709d4 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 632ae77..2ad574d 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-$(CONFIG_MMU) += process_vm_access.o endif -obj-y := filemap.o mempool.o oom_kill.o fadvise.o \ +obj-y := filemap.o mempool.o oom_kill.o \ maccess.o page_alloc.o page-writeback.o \ readahead.o swap.o truncate.o vmscan.o shmem.o \ util.o mmzone.o vmstat.o backing-dev.o \ @@ -28,6 +28,10 @@ else obj-y += bootmem.o endif +obj-$(CONFIG_ADVISE_SYSCALLS) += fadvise.o +ifdef CONFIG_MMU + obj-$(CONFIG_ADVISE_SYSCALLS) += madvise.o +endif obj-$(CONFIG_HAVE_MEMBLOCK) += memblock.o obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o -- 2.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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