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authorKalesh Singh <kaleshsingh@google.com>2020-12-15 06:07:30 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-15 23:13:40 +0300
commitc49dd340180260c6239e453263a9a244da9a7c85 (patch)
tree73407ec73d4e1345adfc342b2597b4e49c638b04 /arch/Kconfig
parent7df666253f2610284f653bce0e2e50b4923c84aa (diff)
downloadlinux-c49dd340180260c6239e453263a9a244da9a7c85.tar.xz
mm: speedup mremap on 1GB or larger regions
Android needs to move large memory regions for garbage collection. The GC requires moving physical pages of multi-gigabyte heap using mremap. During this move, the application threads have to be paused for correctness. It is critical to keep this pause as short as possible to avoid jitters during user interaction. Optimize mremap for >= 1GB-sized regions by moving at the PUD/PGD level if the source and destination addresses are PUD-aligned. For CONFIG_PGTABLE_LEVELS == 3, moving at the PUD level in effect moves PGD entries, since the PUD entry is “folded back” onto the PGD entry. Add HAVE_MOVE_PUD so that architectures where moving at the PUD level isn't supported/tested can turn this off by not selecting the config. Link: https://lkml.kernel.org/r/20201014005320.2233162-4-kaleshsingh@google.com Signed-off-by: Kalesh Singh <kaleshsingh@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: kernel test robot <lkp@intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Geffon <bgeffon@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: Gavin Shan <gshan@redhat.com> Cc: Hassan Naveed <hnaveed@wavecomp.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jia He <justin.he@arm.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kees Cook <keescook@chromium.org> Cc: Krzysztof Kozlowski <krzk@kernel.org> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mina Almasry <almasrymina@google.com> Cc: Minchan Kim <minchan@google.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Ram Pai <linuxram@us.ibm.com> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Sandipan Das <sandipan@linux.ibm.com> Cc: SeongJae Park <sjpark@amazon.de> Cc: Shuah Khan <shuah@kernel.org> Cc: Steven Price <steven.price@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/Kconfig')
-rw-r--r--arch/Kconfig7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/Kconfig b/arch/Kconfig
index 4f654c149709..54a240b61f56 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -648,6 +648,13 @@ config HAVE_IRQ_TIME_ACCOUNTING
Archs need to ensure they use a high enough resolution clock to
support irq time accounting and then call enable_sched_clock_irqtime().
+config HAVE_MOVE_PUD
+ bool
+ help
+ Architectures that select this are able to move page tables at the
+ PUD level. If there are only 3 page table levels, the move effectively
+ happens at the PGD level.
+
config HAVE_MOVE_PMD
bool
help