Patch "mm/rmap: batched invalidations should use existing api" has been added to the 4.4-stable tree
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This is a note to let you know that I've just added the patch titled
mm/rmap: batched invalidations should use existing api
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-rmap-batched-invalidations-should-use-existing-api.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.
Quoted 1 line
From
858eaaa711700ce4595e039441e239e56d7b9514Mon Sep 17 00:00:00 2001
From: Nadav Amit <[email protected]>
Date: Fri, 1 Apr 2016 14:31:26 -0700
Subject: mm/rmap: batched invalidations should use existing api
From: Nadav Amit <[email protected]>
commit 858eaaa711700ce4595e039441e239e56d7b9514 upstream.
The recently introduced batched invalidations mechanism uses its own mechanism for shootdown. However, it does wrong accounting of interrupts (e.g., inc_irq_stat is called for local invalidations), trace-points (e.g., TLB_REMOTE_SHOOTDOWN for local invalidations) and may break some platforms as it bypasses the invalidation mechanisms of Xen and SGI UV.
This patch reuses the existing TLB flushing mechnaisms instead. We use NULL as mm to indicate a global invalidation is required.
Fixes 72b252aed506b8 ("mm: send one IPI per CPU to TLB flush all entries after unmapping pages")
--- arch/x86/include/asm/tlbflush.h | 6 ------ arch/x86/mm/tlb.c | 2 +- mm/rmap.c | 28 +++++++--------------------- 3 files changed, 8 insertions(+), 28 deletions(-)
arch/x86/include/asm/tlbflush.h +0 -6
@@ -325,12 +325,6 @@ static inline void reset_lazy_tlbstate(v#endif /* SMP */ -/* Not inlined due to inc_irq_stat not being defined yet */ -#define flush_tlb_local () { \ - inc_irq_stat(irq_tlb_count); \ - local_flush_tlb(); \ -} -#ifndef CONFIG_PARAVIRT #define flush_tlb_others (mask, mm, start, end) \ native_flush_tlb_others(mask, mm, start, end)
arch/x86/mm/tlb.c +1 -1
@@ -104,7 +104,7 @@ static void flush_tlb_func(void *info)inc_irq_stat (irq_tlb_count); -if (f->flush_mm !=this_cpu_read (cpu_tlbstate.active_mm)) +if (f->flush_mm && f->flush_mm !=this_cpu_read (cpu_tlbstate.active_mm))return ;count_vm_tlb_event (NR_TLB_REMOTE_FLUSH_RECEIVED );
mm/rmap.c +7 -21
@@ -587,19 +587,6 @@ vma_address(struct page *page, struct vm }#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH -static void percpu_flush_tlb_batch_pages (void *data) -{ -/* -* All TLB entries are flushed on the assumption that it is -* cheaper to flush all TLBs and let them be refilled than -* flushing individual PFNs. Note that we do not track mm's -* to flush as that might simply be multiple full TLB flushes -* for no gain. -*/ -count_vm_tlb_event (NR_TLB_REMOTE_FLUSH_RECEIVED ); -flush_tlb_local (); -} -/* * Flush TLB entries for recently unmapped pages from remote CPUs. It is * important if a PTE was dirty when it was unmapped that it's flushed
@@ -616,15 +603,14 @@ void try_to_unmap_flush(void) cpu =get_cpu (); -trace_tlb_flush (TLB_REMOTE_SHOOTDOWN ,-1UL ); - -if (cpumask_test_cpu (cpu, &tlb_ubc->cpumask)) -percpu_flush_tlb_batch_pages (&tlb_ubc->cpumask); - -if (cpumask_any_but (&tlb_ubc->cpumask, cpu) < nr_cpu_ids) { -smp_call_function_many (&tlb_ubc->cpumask, - percpu_flush_tlb_batch_pages, (void *)tlb_ubc, true); +if (cpumask_test_cpu (cpu, &tlb_ubc->cpumask)) { +count_vm_tlb_event (NR_TLB_LOCAL_FLUSH_ALL ); +local_flush_tlb (); +trace_tlb_flush (TLB_LOCAL_SHOOTDOWN ,TLB_FLUSH_ALL ); } + +if (cpumask_any_but (&tlb_ubc->cpumask, cpu) < nr_cpu_ids) +flush_tlb_others (&tlb_ubc->cpumask,NULL ,0 ,TLB_FLUSH_ALL );cpumask_clear (&tlb_ubc->cpumask); tlb_ubc->flush_required = false; tlb_ubc->writable = false;
Patches currently in stable-queue which might be from [email protected] are
queue-4.4/mm-rmap-batched-invalidations-should-use-existing-api.patch