Re: [PATCH 01/25] tile: Fix __pte_free_tlb
From: Chris Metcalf <hidden>
Date: 2011-02-04 20:39:12
Also in:
linux-mm, lkml
On 1/25/2011 12:31 PM, Peter Zijlstra wrote:
Tile's __pte_free_tlb() implementation makes assumptions about the generic mmu_gather implementation, cure this ;-)
I assume you will take this patch into your tree? If so: Acked-by: Chris Metcalf <redacted>
[ Chris, from a quick look L2_USER_PGTABLE_PAGES is something like: 1 << (24 - 16 + 3), which looks awefully large for an on-stack array. ]
Yes, the pte_pages[] array in this routine is 2KB currently. Currently we ship with 64KB pagesize, so the kernel stack has plenty of room. I do like that your patch removes this buffer, however, since we're currently looking into (re-)supporting 4KB pages, which would totally blow the kernel stack in this routine.
quoted hunk ↗ jump to hunk
Cc: Chris Metcalf <redacted> Signed-off-by: Peter Zijlstra <redacted> --- arch/tile/mm/pgtable.c | 15 ++------------- 1 file changed, 2 insertions(+), 13 deletions(-) Index: linux-2.6/arch/tile/mm/pgtable.c ===================================================================--- linux-2.6.orig/arch/tile/mm/pgtable.c +++ linux-2.6/arch/tile/mm/pgtable.c@@ -252,19 +252,8 @@ void __pte_free_tlb(struct mmu_gather *t int i; pgtable_page_dtor(pte); - tlb->need_flush = 1; - if (tlb_fast_mode(tlb)) { - struct page *pte_pages[L2_USER_PGTABLE_PAGES]; - for (i = 0; i < L2_USER_PGTABLE_PAGES; ++i) - pte_pages[i] = pte + i; - free_pages_and_swap_cache(pte_pages, L2_USER_PGTABLE_PAGES); - return; - } - for (i = 0; i < L2_USER_PGTABLE_PAGES; ++i) { - tlb->pages[tlb->nr++] = pte + i; - if (tlb->nr >= FREE_PTE_NR) - tlb_flush_mmu(tlb, 0, 0); - } + for (i = 0; i < L2_USER_PGTABLE_PAGES; ++i) + tlb_remove_page(tlb, pte + i); } #ifndef __tilegx__
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