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authorWill Deacon <will@kernel.org>2021-01-27 23:53:44 +0000
committerPeter Zijlstra <peterz@infradead.org>2021-01-29 20:02:29 +0100
commitd8b450530b90f8845ab962af18b8a10ed77fc889 (patch)
tree5399ddb38a5f0a743c07866a32bec5ce46175b61 /include/asm-generic/tlb.h
parentae8eba8b5d723a4ca543024b6e51f4d0f4fb6b6b (diff)
downloadlinux-d8b450530b90f8845ab962af18b8a10ed77fc889.tar.gz
tlb: mmu_gather: Introduce tlb_gather_mmu_fullmm()
Passing the range '0, -1' to tlb_gather_mmu() sets the 'fullmm' flag, which indicates that the mm_struct being operated on is going away. In this case, some architectures (such as arm64) can elide TLB invalidation by ensuring that the TLB tag (ASID) associated with this mm is not immediately reclaimed. Although this behaviour is documented in asm-generic/tlb.h, it's subtle and easily missed. Introduce tlb_gather_mmu_fullmm() to make it clearer that this is for the entire mm and WARN() if tlb_gather_mmu() is called with the 'fullmm' address range. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Yu Zhao <yuzhao@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lkml.kernel.org/r/20210127235347.1402-4-will@kernel.org
Diffstat (limited to 'include/asm-generic/tlb.h')
-rw-r--r--include/asm-generic/tlb.h6
1 files changed, 4 insertions, 2 deletions
diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index 6661ee1cff47..2c68a545ffa7 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -46,7 +46,9 @@
*
* The mmu_gather API consists of:
*
- * - tlb_gather_mmu() / tlb_finish_mmu(); start and finish a mmu_gather
+ * - tlb_gather_mmu() / tlb_gather_mmu_fullmm() / tlb_finish_mmu()
+ *
+ * start and finish a mmu_gather
*
* Finish in particular will issue a (final) TLB invalidate and free
* all (remaining) queued pages.
@@ -91,7 +93,7 @@
*
* - mmu_gather::fullmm
*
- * A flag set by tlb_gather_mmu() to indicate we're going to free
+ * A flag set by tlb_gather_mmu_fullmm() to indicate we're going to free
* the entire mm; this allows a number of optimizations.
*
* - We can ignore tlb_{start,end}_vma(); because we don't