[PATCH] memblock: make keeping memblock memory opt-in rather than opt-out

STALE2720d

From: Mike Rapoport <hidden>
Date: 2019-04-24 10:36:13
Also in: kexec, linux-arm-kernel, linux-mips, linux-mm, linux-s390, linux-sh, lkml
Subsystem: arm port, arm64 port (aarch64 architecture), kexec, linux for powerpc (32-bit and 64-bit), m68k architecture, memblock and memory management initialization, memory management, memory management - core, memory management - page allocator, mips, nios2 architecture, qualcomm hexagon architecture, s390 architecture, superh, the rest, x86 architecture (32-bit and 64-bit) · Maintainers: Russell King, Catalin Marinas, Will Deacon, Andrew Morton, Baoquan He, Mike Rapoport, Pasha Tatashin, Pratyush Yadav, Madhavan Srinivasan, Geert Uytterhoeven, David Hildenbrand, Vlastimil Babka, Thomas Bogendoerfer, Dinh Nguyen, Simon Schuster, Brian Cain, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Yoshinori Sato, Rich Felker, John Paul Adrian Glaubitz, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen

Most architectures do not need the memblock memory after the page allocator
is initialized, but only few enable ARCH_DISCARD_MEMBLOCK in the
arch Kconfig.

Replacing ARCH_DISCARD_MEMBLOCK with ARCH_KEEP_MEMBLOCK and inverting the
logic makes it clear which architectures actually use memblock after system
initialization and skips the necessity to add ARCH_DISCARD_MEMBLOCK to the
architectures that are still missing that option.

Signed-off-by: Mike Rapoport <redacted>
---
 arch/arm/Kconfig         |  2 +-
 arch/arm64/Kconfig       |  1 +
 arch/hexagon/Kconfig     |  1 -
 arch/ia64/Kconfig        |  1 -
 arch/m68k/Kconfig        |  1 -
 arch/mips/Kconfig        |  1 -
 arch/nios2/Kconfig       |  1 -
 arch/powerpc/Kconfig     |  1 +
 arch/s390/Kconfig        |  1 +
 arch/sh/Kconfig          |  1 -
 arch/x86/Kconfig         |  1 -
 include/linux/memblock.h |  3 ++-
 kernel/kexec_file.c      | 16 ++++++++--------
 mm/Kconfig               |  2 +-
 mm/memblock.c            |  6 +++---
 mm/page_alloc.c          |  3 +--
 16 files changed, 19 insertions(+), 23 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 850b480..7073436 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig

@@ -4,7 +4,6 @@ config ARM
 	default y
 	select ARCH_32BIT_OFF_T
 	select ARCH_CLOCKSOURCE_DATA
-	select ARCH_DISCARD_MEMBLOCK if !HAVE_ARCH_PFN_VALID && !KEXEC
 	select ARCH_HAS_DEBUG_VIRTUAL if MMU
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
 	select ARCH_HAS_ELF_RANDOMIZE

@@ -21,6 +20,7 @@ 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_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

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 7e34b9e..d71f043 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig

@@ -58,6 +58,7 @@ config ARM64
 	select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPT
 	select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPT
 	select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPT
+	select ARCH_KEEP_MEMBLOCK
 	select ARCH_USE_CMPXCHG_LOCKREF
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS

diff --git a/arch/hexagon/Kconfig b/arch/hexagon/Kconfig
index ac44168..bbe3819 100644
--- a/arch/hexagon/Kconfig
+++ b/arch/hexagon/Kconfig

@@ -22,7 +22,6 @@ config HEXAGON
 	select GENERIC_IRQ_SHOW
 	select HAVE_ARCH_KGDB
 	select HAVE_ARCH_TRACEHOOK
-	select ARCH_DISCARD_MEMBLOCK
 	select NEED_SG_DMA_LENGTH
 	select NO_IOPORT_MAP
 	select GENERIC_IOMAP

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 8d7396b..bd51d3b 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig

@@ -33,7 +33,6 @@ config IA64
 	select ARCH_HAS_DMA_COHERENT_TO_PFN if SWIOTLB
 	select ARCH_HAS_SYNC_DMA_FOR_CPU if SWIOTLB
 	select VIRT_TO_BUS
-	select ARCH_DISCARD_MEMBLOCK
 	select GENERIC_IRQ_PROBE
 	select GENERIC_PENDING_IRQ if SMP
 	select GENERIC_IRQ_SHOW

diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index b542064..7d1e5d9 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig

@@ -27,7 +27,6 @@ config M68K
 	select MODULES_USE_ELF_RELA
 	select OLD_SIGSUSPEND3
 	select OLD_SIGACTION
-	select ARCH_DISCARD_MEMBLOCK
 
 config CPU_BIG_ENDIAN
 	def_bool y

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 4a5f5b0..8b9298b 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig

@@ -5,7 +5,6 @@ config MIPS
 	select ARCH_32BIT_OFF_T if !64BIT
 	select ARCH_BINFMT_ELF_STATE if MIPS_FP_SUPPORT
 	select ARCH_CLOCKSOURCE_DATA
-	select ARCH_DISCARD_MEMBLOCK
 	select ARCH_HAS_ELF_RANDOMIZE
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_HAS_UBSAN_SANITIZE_ALL

diff --git a/arch/nios2/Kconfig b/arch/nios2/Kconfig
index 4ef15a6..dc4239c 100644
--- a/arch/nios2/Kconfig
+++ b/arch/nios2/Kconfig

@@ -23,7 +23,6 @@ config NIOS2
 	select SPARSE_IRQ
 	select USB_ARCH_HAS_HCD if USB_SUPPORT
 	select CPU_NO_EFFICIENT_FFS
-	select ARCH_DISCARD_MEMBLOCK
 
 config GENERIC_CSUM
 	def_bool y

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 2d0be82..39877b9 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig

@@ -143,6 +143,7 @@ config PPC
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
 	select ARCH_HAS_ZONE_DEVICE		if PPC_BOOK3S_64
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
+	select ARCH_KEEP_MEMBLOCK
 	select ARCH_MIGHT_HAVE_PC_PARPORT
 	select ARCH_MIGHT_HAVE_PC_SERIO
 	select ARCH_OPTIONAL_KERNEL_RWX		if ARCH_HAS_STRICT_KERNEL_RWX

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index b6e3d06..3eaf660 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig

@@ -106,6 +106,7 @@ config S390
 	select ARCH_INLINE_WRITE_UNLOCK_BH
 	select ARCH_INLINE_WRITE_UNLOCK_IRQ
 	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
+	select ARCH_KEEP_MEMBLOCK
 	select ARCH_SAVE_PAGE_KEYS if HIBERNATION
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_SUPPORTS_NUMA_BALANCING

diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index b1c91ea..418e928 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig

@@ -10,7 +10,6 @@ config SUPERH
 	select DMA_DECLARE_COHERENT
 	select HAVE_IDE if HAS_IOPORT_MAP
 	select HAVE_MEMBLOCK_NODE_MAP
-	select ARCH_DISCARD_MEMBLOCK
 	select HAVE_OPROFILE
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_PERF_EVENTS

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 62fc3fd..80bc582 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig

@@ -48,7 +48,6 @@ config X86
 	select ARCH_32BIT_OFF_T			if X86_32
 	select ARCH_CLOCKSOURCE_DATA
 	select ARCH_CLOCKSOURCE_INIT
-	select ARCH_DISCARD_MEMBLOCK
 	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
 	select ARCH_HAS_DEBUG_VIRTUAL
 	select ARCH_HAS_DEVMEM_IS_ALLOWED

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 294d5d8..6ba69ba 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h

@@ -96,13 +96,14 @@ struct memblock {
 extern struct memblock memblock;
 extern int memblock_debug;
 
-#ifdef CONFIG_ARCH_DISCARD_MEMBLOCK
+#ifndef CONFIG_ARCH_KEEP_MEMBLOCK
 #define __init_memblock __meminit
 #define __initdata_memblock __meminitdata
 void memblock_discard(void);
 #else
 #define __init_memblock
 #define __initdata_memblock
+static inline void memblock_discard(void) {}
 #endif
 
 #define memblock_dbg(fmt, ...) \

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index f1d0e00..623b022 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c

@@ -500,13 +500,7 @@ static int locate_mem_hole_callback(struct resource *res, void *arg)
 	return locate_mem_hole_bottom_up(start, end, kbuf);
 }
 
-#ifdef CONFIG_ARCH_DISCARD_MEMBLOCK
-static int kexec_walk_memblock(struct kexec_buf *kbuf,
-			       int (*func)(struct resource *, void *))
-{
-	return 0;
-}
-#else
+#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
 static int kexec_walk_memblock(struct kexec_buf *kbuf,
 			       int (*func)(struct resource *, void *))
 {

@@ -550,6 +544,12 @@ static int kexec_walk_memblock(struct kexec_buf *kbuf,
 
 	return ret;
 }
+#else
+static int kexec_walk_memblock(struct kexec_buf *kbuf,
+			       int (*func)(struct resource *, void *))
+{
+	return 0;
+}
 #endif
 
 /**

@@ -589,7 +589,7 @@ int kexec_locate_mem_hole(struct kexec_buf *kbuf)
 	if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
 		return 0;
 
-	if (IS_ENABLED(CONFIG_ARCH_DISCARD_MEMBLOCK))
+	if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
 		ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
 	else
 		ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);

diff --git a/mm/Kconfig b/mm/Kconfig
index 25c71eb..1e1c6ce 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig

@@ -136,7 +136,7 @@ config HAVE_MEMBLOCK_PHYS_MAP
 config HAVE_GENERIC_GUP
 	bool
 
-config ARCH_DISCARD_MEMBLOCK
+config ARCH_KEEP_MEMBLOCK
 	bool
 
 config MEMORY_ISOLATION

diff --git a/mm/memblock.c b/mm/memblock.c
index e7665cf..d6b5755 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c

@@ -94,7 +94,7 @@
  * :c:func:`mem_init` function frees all the memory to the buddy page
  * allocator.
  *
- * If an architecure enables %CONFIG_ARCH_DISCARD_MEMBLOCK, the
+ * Unless an architecure enables %CONFIG_ARCH_KEEP_MEMBLOCK, the
  * memblock data structures will be discarded after the system
  * initialization compltes.
  */

@@ -375,7 +375,7 @@ static void __init_memblock memblock_remove_region(struct memblock_type *type, u
 	}
 }
 
-#ifdef CONFIG_ARCH_DISCARD_MEMBLOCK
+#ifndef CONFIG_ARCH_KEEP_MEMBLOCK
 /**
  * memblock_discard - discard memory and reserved arrays if they were allocated
  */

@@ -1923,7 +1923,7 @@ unsigned long __init memblock_free_all(void)
 	return pages;
 }
 
-#if defined(CONFIG_DEBUG_FS) && !defined(CONFIG_ARCH_DISCARD_MEMBLOCK)
+#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_ARCH_KEEP_MEMBLOCK)
 
 static int memblock_debug_show(struct seq_file *m, void *private)
 {

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c6ce20a..a1825e9 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c

@@ -1831,10 +1831,9 @@ void __init page_alloc_init_late(void)
 	/* Reinit limits that are based on free pages after the kernel is up */
 	files_maxfiles_init();
 #endif
-#ifdef CONFIG_ARCH_DISCARD_MEMBLOCK
+
 	/* Discard memblock private memory */
 	memblock_discard();
-#endif
 
 	for_each_populated_zone(zone)
 		set_zone_contiguous(zone);

-- 
2.7.4

`h`	back out one level
`j`	next message in thread
`k`	previous message in thread
`l`	drill in
`Esc`	close help / fold thread tree
`?`	toggle this help