From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <462D713D.6050401@redhat.com> Date: Mon, 23 Apr 2007 22:53:49 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH] lazy freeing of memory through MADV_FREE References: <46247427.6000902@redhat.com> <20070420135715.f6e8e091.akpm@linux-foundation.org> <462932BE.4020005@redhat.com> <20070420150618.179d31a4.akpm@linux-foundation.org> <4629524C.5040302@redhat.com> <462ACA40.8070407@yahoo.com.au> <462B0156.9020407@redhat.com> <462BFAF3.4040509@yahoo.com.au> <462C2DC7.5070709@redhat.com> <462C2F33.8090508@redhat.com> <462C7A6F.9030905@redhat.com> <462C88B1.8080906@yahoo.com.au> <462C8B0A.8060801@redhat.com> <462C8BFF.2050405@yahoo.com.au> In-Reply-To: <462C8BFF.2050405@yahoo.com.au> Content-Type: multipart/mixed; boundary="------------060905040101000808040608" Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: Andrew Morton , linux-kernel , linux-mm , shak , jakub@redhat.com, drepper@redhat.com List-ID: This is a multi-part message in MIME format. --------------060905040101000808040608 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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 -- 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. --------------060905040101000808040608 Content-Type: text/x-patch; name="linux-2.6-madv_free-flushme.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="linux-2.6-madv_free-flushme.patch" --- 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; --------------060905040101000808040608-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org