From c7cc58a1ad8dfe3c199d3b6ce50412b86dd3edaf Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Thu, 23 Jul 2009 23:15:28 +0000 Subject: powerpc/mm: Rework & cleanup page table freeing code path That patch used to just add a hook to page table flushing but pulling that string brought out a whole bunch of issues, so it now does that and more: - We now make the RCU batching of page freeing SMP only, as I believe it was intended initially. We make a few more things compile to nothing on !CONFIG_SMP - Some macros are turned into functions, though that forced me to out of line a few stuffs due to unsolvable include depenencies, however it's probably better that way anyway, it's not -that- critical code path. - 32-bit didn't call pte_free_finish() on tlb_flush() which means that it wouldn't push out the batch to RCU for delayed freeing when a bunch of page tables have been freed, they would just stay in there until the batch gets full. 64-bit BookE will use that hook to maintain the virtually linear page tables or the indirect entries in the TLB when using the HW loader. Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/mm/pgtable.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'arch/powerpc/mm/pgtable.c') diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c index 627767d6169..a65979a5f75 100644 --- a/arch/powerpc/mm/pgtable.c +++ b/arch/powerpc/mm/pgtable.c @@ -30,6 +30,14 @@ #include #include +#ifdef CONFIG_SMP + +/* + * Handle batching of page table freeing on SMP. Page tables are + * queued up and send to be freed later by RCU in order to avoid + * freeing a page table page that is being walked without locks + */ + static DEFINE_PER_CPU(struct pte_freelist_batch *, pte_freelist_cur); static unsigned long pte_freelist_forced_free; @@ -116,6 +124,8 @@ void pte_free_finish(void) *batchp = NULL; } +#endif /* CONFIG_SMP */ + /* * Handle i/d cache flushing, called from set_pte_at() or ptep_set_access_flags() */ -- cgit v1.2.3-70-g09d2