kevin/linux
1
Fork 0
Code

arm: remove CONFIG_ARCH_HAS_HOLES_MEMORYMODEL

Browse Source 
ARM is the only architecture that defines CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
which in turn enables memmap_valid_within() function that is intended to
verify existence  of struct page associated with a pfn when there are holes
in the memory map.

However, the ARCH_HAS_HOLES_MEMORYMODEL also enables HAVE_ARCH_PFN_VALID
and arch-specific pfn_valid() implementation that also deals with the holes
in the memory map.

The only two users of memmap_valid_within() call this function after
a call to pfn_valid() so the memmap_valid_within() check becomes redundant.

Remove CONFIG_ARCH_HAS_HOLES_MEMORYMODEL and memmap_valid_within() and rely
entirely on ARM's implementation of pfn_valid() that is now enabled
unconditionally.

Link: https://lkml.kernel.org/r/20201101170454.9567-9-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Meelis Roos <mroos@linux.ee>
Cc: Michael Schmitz <schmitzmic@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mike Rapoport 2020-12-14 19:09:55 -08:00 committed by Linus Torvalds
parent 214496cb18
commit 5e545df329
13 changed files with 3 additions and 66 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
Documentation/vm/memory-model.rst
View File

@ -51,8 +51,7 @@ call :c:func:`free_area_init` function. Yet, the mappings array is not
usable until the call to :c:func:`memblock_free_all` that hands all the
memory to the page allocator.
If an architecture enables `CONFIG_ARCH_HAS_HOLES_MEMORYMODEL` option,
it may free parts of the `mem_map` array that do not cover the
An architecture may free parts of the `mem_map` array that do not cover the
actual physical pages. In such case, the architecture specific
:c:func:`pfn_valid` implementation should take the holes in the
`mem_map` into account.

8
arch/arm/Kconfig
View File

@ -25,7 +25,7 @@ config ARM
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAVE_CUSTOM_GPIO_H
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_KEEP_MEMBLOCK if HAVE_ARCH_PFN_VALID || KEXEC
select ARCH_KEEP_MEMBLOCK
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_NO_SG_CHAIN if !ARM_HAS_SG_CHAIN
select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
@ -520,7 +520,6 @@ config ARCH_S3C24XX
config ARCH_OMAP1
bool "TI OMAP1"
depends on MMU
select ARCH_HAS_HOLES_MEMORYMODEL
select ARCH_OMAP
select CLKDEV_LOOKUP
select CLKSRC_MMIO
@ -1480,9 +1479,6 @@ config OABI_COMPAT
UNPREDICTABLE (in fact it can be predicted that it won't work
at all). If in doubt say N.
config ARCH_HAS_HOLES_MEMORYMODEL
bool
config ARCH_SELECT_MEMORY_MODEL
bool
@ -1494,7 +1490,7 @@ config ARCH_SPARSEMEM_ENABLE
select SPARSEMEM_STATIC if SPARSEMEM
config HAVE_ARCH_PFN_VALID
def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM
def_bool y
config HIGHMEM
bool "High Memory Support"

1
arch/arm/mach-bcm/Kconfig
View File

@ -211,7 +211,6 @@ config ARCH_BRCMSTB
select BCM7038_L1_IRQ
select BRCMSTB_L2_IRQ
select BCM7120_L2_IRQ
select ARCH_HAS_HOLES_MEMORYMODEL
select ZONE_DMA if ARM_LPAE
select SOC_BRCMSTB
select SOC_BUS

1
arch/arm/mach-davinci/Kconfig
View File

@ -5,7 +5,6 @@ menuconfig ARCH_DAVINCI
depends on ARCH_MULTI_V5
select DAVINCI_TIMER
select ZONE_DMA
select ARCH_HAS_HOLES_MEMORYMODEL
select PM_GENERIC_DOMAINS if PM
select PM_GENERIC_DOMAINS_OF if PM && OF
select REGMAP_MMIO

1
arch/arm/mach-exynos/Kconfig
View File

@ -8,7 +8,6 @@
menuconfig ARCH_EXYNOS
bool "Samsung Exynos"
depends on ARCH_MULTI_V7
select ARCH_HAS_HOLES_MEMORYMODEL
select ARCH_SUPPORTS_BIG_ENDIAN
select ARM_AMBA
select ARM_GIC

1
arch/arm/mach-highbank/Kconfig
View File

@ -2,7 +2,6 @@
config ARCH_HIGHBANK
bool "Calxeda ECX-1000/2000 (Highbank/Midway)"
depends on ARCH_MULTI_V7
select ARCH_HAS_HOLES_MEMORYMODEL
select ARCH_SUPPORTS_BIG_ENDIAN
select ARM_AMBA
select ARM_ERRATA_764369 if SMP

1
arch/arm/mach-omap2/Kconfig
View File

@ -93,7 +93,6 @@ config SOC_DRA7XX
config ARCH_OMAP2PLUS
bool
select ARCH_HAS_BANDGAP
select ARCH_HAS_HOLES_MEMORYMODEL
select ARCH_HAS_RESET_CONTROLLER
select ARCH_OMAP
select CLKSRC_MMIO

1
arch/arm/mach-s5pv210/Kconfig
View File

@ -8,7 +8,6 @@
config ARCH_S5PV210
bool "Samsung S5PV210/S5PC110"
depends on ARCH_MULTI_V7
select ARCH_HAS_HOLES_MEMORYMODEL
select ARM_VIC
select CLKSRC_SAMSUNG_PWM
select COMMON_CLK_SAMSUNG

1
arch/arm/mach-tango/Kconfig
View File

@ -3,7 +3,6 @@ config ARCH_TANGO
bool "Sigma Designs Tango4 (SMP87xx)"
depends on ARCH_MULTI_V7
# Cortex-A9 MPCore r3p0, PL310 r3p2
select ARCH_HAS_HOLES_MEMORYMODEL
select ARM_ERRATA_754322
select ARM_ERRATA_764369 if SMP
select ARM_ERRATA_775420

2
fs/proc/kcore.c
View File

@ -193,8 +193,6 @@ kclist_add_private(unsigned long pfn, unsigned long nr_pages, void *arg)
return 1;
p = pfn_to_page(pfn);
if (!memmap_valid_within(pfn, p, page_zone(p)))
return 1;
ent = kmalloc(sizeof(*ent), GFP_KERNEL);
if (!ent)

31
include/linux/mmzone.h
View File

@ -1440,37 +1440,6 @@ void sparse_init(void);
#define pfn_valid_within(pfn) (1)
#endif
#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
/*
* pfn_valid() is meant to be able to tell if a given PFN has valid memmap
* associated with it or not. This means that a struct page exists for this
* pfn. The caller cannot assume the page is fully initialized in general.
* Hotplugable pages might not have been onlined yet. pfn_to_online_page()
* will ensure the struct page is fully online and initialized. Special pages
* (e.g. ZONE_DEVICE) are never onlined and should be treated accordingly.
*
* In FLATMEM, it is expected that holes always have valid memmap as long as
* there is valid PFNs either side of the hole. In SPARSEMEM, it is assumed
* that a valid section has a memmap for the entire section.
*
* However, an ARM, and maybe other embedded architectures in the future
* free memmap backing holes to save memory on the assumption the memmap is
* never used. The page_zone linkages are then broken even though pfn_valid()
* returns true. A walker of the full memmap must then do this additional
* check to ensure the memmap they are looking at is sane by making sure
* the zone and PFN linkages are still valid. This is expensive, but walkers
* of the full memmap are extremely rare.
*/
bool memmap_valid_within(unsigned long pfn,
struct page *page, struct zone *zone);
#else
static inline bool memmap_valid_within(unsigned long pfn,
struct page *page, struct zone *zone)
{
return true;
}
#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
#endif /* !__GENERATING_BOUNDS.H */
#endif /* !__ASSEMBLY__ */
#endif /* _LINUX_MMZONE_H */

14
mm/mmzone.c
View File

@ -72,20 +72,6 @@ struct zoneref *__next_zones_zonelist(struct zoneref *z,
return z;
}
#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
bool memmap_valid_within(unsigned long pfn,
struct page *page, struct zone *zone)
{
if (page_to_pfn(page) != pfn)
return false;
if (page_zone(page) != zone)
return false;
return true;
}
#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
void lruvec_init(struct lruvec *lruvec)
{
enum lru_list lru;

4
mm/vmstat.c
View File

@ -1503,10 +1503,6 @@ static void pagetypeinfo_showblockcount_print(struct seq_file *m,
if (!page)
continue;
/* Watch for unexpected holes punched in the memmap */
if (!memmap_valid_within(pfn, page, zone))
continue;
if (page_zone(page) != zone)
continue;