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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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3ccfebedd8
Allow PowerPC to skip the full memory barrier in switch_mm(), and only issue the barrier when scheduling into a task belonging to a process that has registered to use expedited private. Threads targeting the same VM but which belong to different thread groups is a tricky case. It has a few consequences: It turns out that we cannot rely on get_nr_threads(p) to count the number of threads using a VM. We can use (atomic_read(&mm->mm_users) == 1 && get_nr_threads(p) == 1) instead to skip the synchronize_sched() for cases where the VM only has a single user, and that user only has a single thread. It also turns out that we cannot use for_each_thread() to set thread flags in all threads using a VM, as it only iterates on the thread group. Therefore, test the membarrier state variable directly rather than relying on thread flags. This means membarrier_register_private_expedited() needs to set the MEMBARRIER_STATE_PRIVATE_EXPEDITED flag, issue synchronize_sched(), and only then set MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY which allows private expedited membarrier commands to succeed. membarrier_arch_switch_mm() now tests for the MEMBARRIER_STATE_PRIVATE_EXPEDITED flag. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andrea Parri <parri.andrea@gmail.com> Cc: Andrew Hunter <ahh@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Avi Kivity <avi@scylladb.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Dave Watson <davejwatson@fb.com> Cc: David Sehr <sehr@google.com> Cc: Greg Hackmann <ghackmann@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maged Michael <maged.michael@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-api@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20180129202020.8515-3-mathieu.desnoyers@efficios.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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| .. | ||
| 8xx_mmu.c | ||
| 40x_mmu.c | ||
| 44x_mmu.c | ||
| copro_fault.c | ||
| dma-noncoherent.c | ||
| dump_hashpagetable.c | ||
| dump_linuxpagetables.c | ||
| fault.c | ||
| fsl_booke_mmu.c | ||
| hash64_4k.c | ||
| hash64_64k.c | ||
| hash_low_32.S | ||
| hash_native_64.c | ||
| hash_utils_64.c | ||
| highmem.c | ||
| hugepage-hash64.c | ||
| hugetlbpage-book3e.c | ||
| hugetlbpage-hash64.c | ||
| hugetlbpage-radix.c | ||
| hugetlbpage.c | ||
| init_32.c | ||
| init_64.c | ||
| init-common.c | ||
| Makefile | ||
| mem.c | ||
| mmap.c | ||
| mmu_context_book3s64.c | ||
| mmu_context_hash32.c | ||
| mmu_context_iommu.c | ||
| mmu_context_nohash.c | ||
| mmu_context.c | ||
| mmu_decl.h | ||
| numa.c | ||
| pgtable_32.c | ||
| pgtable_64.c | ||
| pgtable-book3e.c | ||
| pgtable-book3s64.c | ||
| pgtable-hash64.c | ||
| pgtable-radix.c | ||
| pgtable.c | ||
| ppc_mmu_32.c | ||
| slb_low.S | ||
| slb.c | ||
| slice.c | ||
| subpage-prot.c | ||
| tlb_hash32.c | ||
| tlb_hash64.c | ||
| tlb_low_64e.S | ||
| tlb_nohash_low.S | ||
| tlb_nohash.c | ||
| tlb-radix.c | ||
| vphn.c | ||
| vphn.h | ||