From b0284cd29a957e62d60c2886fd663be93c56f9c0 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Thu, 3 Nov 2022 18:10:34 -0700 Subject: mm: Do not enable PG_arch_2 for all 64-bit architectures Commit 4beba9486abd ("mm: Add PG_arch_2 page flag") introduced a new page flag for all 64-bit architectures. However, even if an architecture is 64-bit, it may still have limited spare bits in the 'flags' member of 'struct page'. This may happen if an architecture enables SPARSEMEM without SPARSEMEM_VMEMMAP as is the case with the newly added loongarch. This architecture port needs 19 more bits for the sparsemem section information and, while it is currently fine with PG_arch_2, adding any more PG_arch_* flags will trigger build-time warnings. Add a new CONFIG_ARCH_USES_PG_ARCH_X option which can be selected by architectures that need more PG_arch_* flags beyond PG_arch_1. Select it on arm64. Signed-off-by: Catalin Marinas [pcc@google.com: fix build with CONFIG_ARM64_MTE disabled] Signed-off-by: Peter Collingbourne Reported-by: kernel test robot Cc: Andrew Morton Cc: Steven Price Reviewed-by: Steven Price Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20221104011041.290951-2-pcc@google.com --- mm/Kconfig | 8 ++++++++ mm/huge_memory.c | 2 +- 2 files changed, 9 insertions(+), 1 deletion(-) (limited to 'mm') diff --git a/mm/Kconfig b/mm/Kconfig index 57e1d8c5b505..807bd7192f51 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -1005,6 +1005,14 @@ config ARCH_USES_HIGH_VMA_FLAGS config ARCH_HAS_PKEYS bool +config ARCH_USES_PG_ARCH_X + bool + help + Enable the definition of PG_arch_x page flags with x > 1. Only + suitable for 64-bit architectures with CONFIG_FLATMEM or + CONFIG_SPARSEMEM_VMEMMAP enabled, otherwise there may not be + enough room for additional bits in page->flags. + config VM_EVENT_COUNTERS default y bool "Enable VM event counters for /proc/vmstat" if EXPERT diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 561a42567477..76e7b973919c 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2444,7 +2444,7 @@ static void __split_huge_page_tail(struct page *head, int tail, (1L << PG_workingset) | (1L << PG_locked) | (1L << PG_unevictable) | -#ifdef CONFIG_64BIT +#ifdef CONFIG_ARCH_USES_PG_ARCH_X (1L << PG_arch_2) | #endif (1L << PG_dirty) | -- cgit v1.2.3 From ef6458b1b6ca3fdb991ce4182e981a88d4c58c0f Mon Sep 17 00:00:00 2001 From: Peter Collingbourne Date: Thu, 3 Nov 2022 18:10:37 -0700 Subject: mm: Add PG_arch_3 page flag As with PG_arch_2, this flag is only allowed on 64-bit architectures due to the shortage of bits available. It will be used by the arm64 MTE code in subsequent patches. Signed-off-by: Peter Collingbourne Cc: Will Deacon Cc: Marc Zyngier Cc: Steven Price [catalin.marinas@arm.com: added flag preserving in __split_huge_page_tail()] Signed-off-by: Catalin Marinas Reviewed-by: Steven Price Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20221104011041.290951-5-pcc@google.com --- fs/proc/page.c | 1 + include/linux/kernel-page-flags.h | 1 + include/linux/page-flags.h | 1 + include/trace/events/mmflags.h | 1 + mm/huge_memory.c | 1 + 5 files changed, 5 insertions(+) (limited to 'mm') diff --git a/fs/proc/page.c b/fs/proc/page.c index 882525c8e94c..6249c347809a 100644 --- a/fs/proc/page.c +++ b/fs/proc/page.c @@ -221,6 +221,7 @@ u64 stable_page_flags(struct page *page) u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1); #ifdef CONFIG_ARCH_USES_PG_ARCH_X u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_2); + u |= kpf_copy_bit(k, KPF_ARCH_3, PG_arch_3); #endif return u; diff --git a/include/linux/kernel-page-flags.h b/include/linux/kernel-page-flags.h index eee1877a354e..859f4b0c1b2b 100644 --- a/include/linux/kernel-page-flags.h +++ b/include/linux/kernel-page-flags.h @@ -18,5 +18,6 @@ #define KPF_UNCACHED 39 #define KPF_SOFTDIRTY 40 #define KPF_ARCH_2 41 +#define KPF_ARCH_3 42 #endif /* LINUX_KERNEL_PAGE_FLAGS_H */ diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 5dc7977edf9d..c50ce2812f17 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -134,6 +134,7 @@ enum pageflags { #endif #ifdef CONFIG_ARCH_USES_PG_ARCH_X PG_arch_2, + PG_arch_3, #endif #ifdef CONFIG_KASAN_HW_TAGS PG_skip_kasan_poison, diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h index d9f6d35fb150..412b5a46374c 100644 --- a/include/trace/events/mmflags.h +++ b/include/trace/events/mmflags.h @@ -131,6 +131,7 @@ IF_HAVE_PG_HWPOISON(PG_hwpoison, "hwpoison" ) \ IF_HAVE_PG_IDLE(PG_young, "young" ) \ IF_HAVE_PG_IDLE(PG_idle, "idle" ) \ IF_HAVE_PG_ARCH_X(PG_arch_2, "arch_2" ) \ +IF_HAVE_PG_ARCH_X(PG_arch_3, "arch_3" ) \ IF_HAVE_PG_SKIP_KASAN_POISON(PG_skip_kasan_poison, "skip_kasan_poison") #define show_page_flags(flags) \ diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 76e7b973919c..dfe72ea23c5f 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2446,6 +2446,7 @@ static void __split_huge_page_tail(struct page *head, int tail, (1L << PG_unevictable) | #ifdef CONFIG_ARCH_USES_PG_ARCH_X (1L << PG_arch_2) | + (1L << PG_arch_3) | #endif (1L << PG_dirty) | LRU_GEN_MASK | LRU_REFS_MASK)); -- cgit v1.2.3