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Commit 00af8484 authored by Zhenhua Huang's avatar Zhenhua Huang Committed by Gerrit - the friendly Code Review server
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mm: Kconfig: Add support for config size of purging vmap_area 



This size is the maximum amount of virtual address space we gather
up before attempting to purge with a TLB flush. It is 128M in most cases.
With repeated and high size vmalloc operations, it may easily generate
more fragments. This is wasting limited vmalloc area, for 32bits.
So make it configable and the default multiplier as 8, 32bits only.

Change-Id: I68a75acb16d3cff05f8b13c05ae78922269e219f
Signed-off-by: default avatarZhenhua Huang <zhenhuah@codeaurora.org>
parent 44496944

mm/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -643,6 +643,16 @@ config ZSMALLOC_STAT 
	  information to userspace via debugfs.

	  If unsure, say N.



config VMAP_LAZY_PURGING_FACTOR

	int "multiplier to the size of purged vmap areas"

	default "8" if ARM

	default "32"

	help

	  It is used as a multiplier to the max VA pages purged in a

	  single attempt. For 32-bit in order to reduce fragmentation

	  of vmalloc space, we decrease the default value to "8".





config GENERIC_EARLY_IOREMAP

	bool

mm/vmalloc.c

+2 −1
Original line number Diff line number Diff line
@@ -1229,7 +1229,8 @@ static unsigned long lazy_max_pages(void) 


	log = fls(num_online_cpus());



	return log * (32UL * 1024 * 1024 / PAGE_SIZE);

	return log * (1UL * CONFIG_VMAP_LAZY_PURGING_FACTOR *

					1024 * 1024 / PAGE_SIZE);

}



static atomic_long_t vmap_lazy_nr = ATOMIC_LONG_INIT(0);