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| author | Will Deacon <will@kernel.org> | 2020-05-26 18:33:01 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-06-02 18:45:51 -0700 |
| commit | 60bccaa671bce7ed040d9511b0738ca3b0a0e9ff (patch) | |
| tree | 4cd661ce17ab6ea6cd8cda944a81335b78fa32f7 /mm/Kconfig | |
| parent | 454b0289c6b5f2c66164654b80212d15fbef7a03 (diff) | |
| download | linux-60bccaa671bce7ed040d9511b0738ca3b0a0e9ff.tar.bz2 | |
sparc32: mm: Disable SPLIT_PTLOCK_CPUS
The SRMMU page-table allocator is not compatible with SPLIT_PTLOCK_CPUS
for two major reasons:
1. Pages are allocated via memblock, and therefore the ptl is not
cleared by prep_new_page(), which is expected by ptlock_init()
2. Multiple PTE tables can exist in a single page, causing them to
share the same ptl and deadlock when attempting to take the same
lock twice (e.g. as part of copy_page_range()).
Ensure that SPLIT_PTLOCK_CPUS is not selected for SPARC32.
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'mm/Kconfig')
| -rw-r--r-- | mm/Kconfig | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig index c1acc34c1c35..97458119cce8 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -192,6 +192,9 @@ config MEMORY_HOTREMOVE # Default to 4 for wider testing, though 8 might be more appropriate. # ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock. # PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes. +# SPARC32 allocates multiple pte tables within a single page, and therefore +# a per-page lock leads to problems when multiple tables need to be locked +# at the same time (e.g. copy_page_range()). # DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock_t also enlarge struct page. # config SPLIT_PTLOCK_CPUS @@ -199,6 +202,7 @@ config SPLIT_PTLOCK_CPUS default "999999" if !MMU default "999999" if ARM && !CPU_CACHE_VIPT default "999999" if PARISC && !PA20 + default "999999" if SPARC32 default "4" config ARCH_ENABLE_SPLIT_PMD_PTLOCK |