CONFIG_BOUNCE to avoid useless inclusion of bounce buffer logic (2a7326b5) · Commits · 戴 / test

The bounce buffer logic is included on systems that do not need it. If a system does not have zones like ZONE_DMA and ZONE_HIGHMEM that can lead to the use of bounce buffers then there is no need to reserve memory pools etc etc. This is true f.e. for SGI Altix. Also nicifies the Makefile and gets rid of the tricky "and" there. Signed-off-by:

Christoph Lameter <clameter@sgi.com> Acked-by:

Jens Axboe <jens.axboe@oracle.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

include/linux/blkdev.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -624,7 +624,7 @@ extern unsigned long blk_max_low_pfn, blk_max_pfn;
		*/
		#define BLK_DEFAULT_SG_TIMEOUT (60 * HZ)

		#ifdef CONFIG_MMU
		#ifdef CONFIG_BOUNCE
		extern int init_emergency_isa_pool(void);
		extern void blk_queue_bounce(request_queue_t q, struct bio *bio);
		#else

mm/Kconfig

+4 −0

Original line number	Diff line number	Diff line
		@@ -163,6 +163,10 @@ config ZONE_DMA_FLAG
		default "0" if !ZONE_DMA
		default "1"

		config BOUNCE
		def_bool y
		depends on BLOCK && MMU && (ZONE_DMA \|\| HIGHMEM)

		config NR_QUICK
		int
		depends on QUICKLIST

mm/Makefile

+1 −3

Original line number	Diff line number	Diff line
		@@ -13,9 +13,7 @@ obj-y := bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \
		prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \
		$(mmu-y)

		ifeq ($(CONFIG_MMU)$(CONFIG_BLOCK),yy)
		obj-y += bounce.o
		endif
		obj-$(CONFIG_BOUNCE) += bounce.o
		obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o thrash.o
		obj-$(CONFIG_HUGETLBFS) += hugetlb.o
		obj-$(CONFIG_NUMA) += mempolicy.o

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