From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 64FF16B0038 for ; Mon, 5 Sep 2016 21:56:02 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id k83so17121485pfa.2 for ; Mon, 05 Sep 2016 18:56:02 -0700 (PDT) Received: from mail-pa0-x244.google.com (mail-pa0-x244.google.com. [2607:f8b0:400e:c03::244]) by mx.google.com with ESMTPS id sq1si32426942pab.29.2016.09.05.18.56.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 05 Sep 2016 18:56:01 -0700 (PDT) Received: by mail-pa0-x244.google.com with SMTP id pp5so3650786pac.2 for ; Mon, 05 Sep 2016 18:56:01 -0700 (PDT) Subject: Re: [RESEND][v2][PATCH] KVM: PPC: Book3S HV: Migrate pinned pages out of CMA References: <20160714042536.GG18277@balbir.ozlabs.ibm.com> <3ba0fa6c-bfe6-a395-9c32-db8d6261559d@ozlabs.ru> From: Balbir Singh Message-ID: Date: Tue, 6 Sep 2016 11:55:54 +1000 MIME-Version: 1.0 In-Reply-To: <3ba0fa6c-bfe6-a395-9c32-db8d6261559d@ozlabs.ru> Content-Type: text/plain; charset=koi8-r Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Alexey Kardashevskiy , linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org, kvm@vger.kernel.org Cc: "linux-mm@kvack.org" , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman On 31/08/16 14:14, Alexey Kardashevskiy wrote: > On 14/07/16 14:25, Balbir Singh wrote: >> >> From: Balbir Singh >> Subject: [RESEND][v2][PATCH] KVM: PPC: Book3S HV: Migrate pinned pages out of CMA >> >> When PCI Device pass-through is enabled via VFIO, KVM-PPC will >> pin pages using get_user_pages_fast(). One of the downsides of >> the pinning is that the page could be in CMA region. The CMA >> region is used for other allocations like the hash page table. >> Ideally we want the pinned pages to be from non CMA region. >> >> This patch (currently only for KVM PPC with VFIO) forcefully >> migrates the pages out (huge pages are omitted for the moment). >> There are more efficient ways of doing this, but that might >> be elaborate and might impact a larger audience beyond just >> the kvm ppc implementation. >> >> The magic is in new_iommu_non_cma_page() which allocates the >> new page from a non CMA region. >> >> I've tested the patches lightly at my end, but there might be bugs >> For example if after lru_add_drain(), the page is not isolated >> is this a BUG? >> >> Previous discussion was at >> http://permalink.gmane.org/gmane.linux.kernel.mm/136738 >> >> Cc: Benjamin Herrenschmidt >> Cc: Michael Ellerman >> Cc: Paul Mackerras >> Cc: Alexey Kardashevskiy >> >> Signed-off-by: Balbir Singh > > > > Acked-by: Alexey Kardashevskiy > Thanks! I tested this patch against latest mainline and here are the test results System RAM - 64GB VM instance 1 - size 55GB Before patch - nr_free_cma after launch 8900 After patch - nr_free_cma after launch 39500 Balbir Singh. -- 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