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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2016-05-25 09:45:26 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2016-06-13 15:58:22 +0200
commit64f31d5802af11fd87872b4bae07b35cf0acb358 (patch)
tree73f514c73762092fd6710efa6863a5a6124d86a3 /arch/s390/mm/init.c
parentbitmap: bitmap_equal memcmp optimization (diff)
downloadlinux-dev-64f31d5802af11fd87872b4bae07b35cf0acb358.tar.xz
linux-dev-64f31d5802af11fd87872b4bae07b35cf0acb358.zip
s390/mm: simplify the TLB flushing code
ptep_flush_lazy and pmdp_flush_lazy use mm->context.attach_count to decide between a lazy TLB flush vs an immediate TLB flush. The field contains two 16-bit counters, the number of CPUs that have the mm attached and can create TLB entries for it and the number of CPUs in the middle of a page table update. The __tlb_flush_asce, ptep_flush_direct and pmdp_flush_direct functions use the attach counter and a mask check with mm_cpumask(mm) to decide between a local flush local of the current CPU and a global flush. For all these functions the decision between lazy vs immediate and local vs global TLB flush can be based on CPU masks. There are two masks: the mm->context.cpu_attach_mask with the CPUs that are actively using the mm, and the mm_cpumask(mm) with the CPUs that have used the mm since the last full flush. The decision between lazy vs immediate flush is based on the mm->context.cpu_attach_mask, to decide between local vs global flush the mm_cpumask(mm) is used. With this patch all checks will use the CPU masks, the old counter mm->context.attach_count with its two 16-bit values is turned into a single counter mm->context.flush_count that keeps track of the number of CPUs with incomplete page table updates. The sole user of this counter is finish_arch_post_lock_switch() which waits for the end of all page table updates. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/mm/init.c')
-rw-r--r--arch/s390/mm/init.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 44db60d9e519..de2cdf4fbb9a 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -118,10 +118,8 @@ void mark_rodata_ro(void)
void __init mem_init(void)
{
- if (MACHINE_HAS_TLB_LC)
- cpumask_set_cpu(0, &init_mm.context.cpu_attach_mask);
+ cpumask_set_cpu(0, &init_mm.context.cpu_attach_mask);
cpumask_set_cpu(0, mm_cpumask(&init_mm));
- atomic_set(&init_mm.context.attach_count, 1);
set_max_mapnr(max_low_pfn);
high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);