Messages in this thread Patch in this message | | | Date | Mon, 23 Apr 2007 22:53:49 -0400 | From | Rik van Riel <> | Subject | Re: [PATCH] lazy freeing of memory through MADV_FREE |
| |
Nick Piggin wrote:
> What the tlb flush used to be able to assume is that the page > has been removed from the pagetables when they are put in the > tlb flush batch.
I think this is still the case, to a degree. There should be no harm in removing the TLB entries after the page table has been unlocked, right?
Or is something like the attached really needed?
From what I can see, the page table lock should be enough synchronization between unmap_mapping_range, MADV_FREE and MADV_DONTNEED.
I don't see why we need the attached, but in case you find a good reason, here's my signed-off-by line for Andrew :)
Signed-off-by: Rik van Riel <riel@redhat.com>
-- Politics is the struggle between those who want to make their country the best in the world, and those who believe it already is. Each group calls the other unpatriotic. --- linux-2.6.20.x86_64/mm/memory.c.flushme 2007-04-23 22:26:06.000000000 -0400 +++ linux-2.6.20.x86_64/mm/memory.c 2007-04-23 22:42:06.000000000 -0400 @@ -628,6 +628,7 @@ static unsigned long zap_pte_range(struc long *zap_work, struct zap_details *details) { struct mm_struct *mm = tlb->mm; + unsigned long start_addr = addr; pte_t *pte; spinlock_t *ptl; int file_rss = 0; @@ -726,6 +727,11 @@ static unsigned long zap_pte_range(struc add_mm_rss(mm, file_rss, anon_rss); arch_leave_lazy_mmu_mode(); + if (details && details->madv_free) { + /* Protect against MADV_DONTNEED or unmap_mapping_range */ + tlb_finish_mmu(tlb, start_addr, addr); + tlb = tlb_gather_mmu(mm, 0); + } pte_unmap_unlock(pte - 1, ptl); return addr; | |