On Thu, Mar 12, 2020 at 06:57:39PM +0530, Santosh Sivaraj wrote:
From: Peter Zijlstra peterz@infradead.org
commit 0ed1325967ab5f7a4549a2641c6ebe115f76e228 upstream.
Architectures for which we have hardware walkers of Linux page table should flush TLB on mmu gather batch allocation failures and batch flush. Some architectures like POWER supports multiple translation modes (hash and radix) and in the case of POWER only radix translation mode needs the above TLBI. This is because for hash translation mode kernel wants to avoid this extra flush since there are no hardware walkers of linux page table. With radix translation, the hardware also walks linux page table and with that, kernel needs to make sure to TLB invalidate page walk cache before page table pages are freed.
More details in commit d86564a2f085 ("mm/tlb, x86/mm: Support invalidating TLB caches for RCU_TABLE_FREE")
The changes to sparc are to make sure we keep the old behavior since we are now removing HAVE_RCU_TABLE_NO_INVALIDATE. The default value for tlb_needs_table_invalidate is to always force an invalidate and sparc can avoid the table invalidate. Hence we define tlb_needs_table_invalidate to false for sparc architecture.
Link: http://lkml.kernel.org/r/20200116064531.483522-3-aneesh.kumar@linux.ibm.com Fixes: a46cc7a90fd8 ("powerpc/mm/radix: Improve TLB/PWC flushes") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org Signed-off-by: Aneesh Kumar K.V aneesh.kumar@linux.ibm.com Cc: stable@vger.kernel.org # 4.19 Signed-off-by: Santosh Sivaraj santosh@fossix.org [santosh: backported to 4.19 stable]
arch/Kconfig | 3 --- arch/powerpc/Kconfig | 1 - arch/powerpc/include/asm/tlb.h | 11 +++++++++++ arch/sparc/Kconfig | 1 - arch/sparc/include/asm/tlb_64.h | 9 +++++++++ include/asm-generic/tlb.h | 15 +++++++++++++++ mm/memory.c | 16 ++++++++-------- 7 files changed, 43 insertions(+), 13 deletions(-)
As the testing pointed out, this breaks the build on lots of arches: https://lore.kernel.org/r/CAEUSe78+F1Q9LFjpf8SQzQa6+Ak4wcPiiNcUVxEcv+KPdrYvB... https://lore.kernel.org/r/cff87cd2-8cd5-241e-3a05-a817b1a56b8c@roeck-us.net
so I'm going to drop this whole series and do a -rc2.
If you still want/need this series in 4.19, please make sure it really works for everyone :)
thanks,
greg k-h