From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id A9D9A1A0025 for ; Mon, 28 Jul 2014 10:44:02 +1000 (EST) Message-ID: <1406508232.4935.23.camel@pasglop> Subject: Re: [PATCH v3 03/18] KVM: PPC: Account TCE pages in locked_vm From: Benjamin Herrenschmidt To: Alexey Kardashevskiy Date: Mon, 28 Jul 2014 10:43:52 +1000 In-Reply-To: <1406191691-31441-4-git-send-email-aik@ozlabs.ru> References: <1406191691-31441-1-git-send-email-aik@ozlabs.ru> <1406191691-31441-4-git-send-email-aik@ozlabs.ru> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Cc: Paul Mackerras , linuxppc-dev@lists.ozlabs.org, Gavin Shan List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 2014-07-24 at 18:47 +1000, Alexey Kardashevskiy wrote: > Signed-off-by: Alexey Kardashevskiy > --- You need a description. > arch/powerpc/kvm/book3s_64_vio.c | 35 ++++++++++++++++++++++++++++++++++- > 1 file changed, 34 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c > index 516f2ee..48b7ed4 100644 > --- a/arch/powerpc/kvm/book3s_64_vio.c > +++ b/arch/powerpc/kvm/book3s_64_vio.c > @@ -45,18 +45,48 @@ static long kvmppc_stt_npages(unsigned long window_size) > * sizeof(u64), PAGE_SIZE) / PAGE_SIZE; > } > > +/* > + * Checks ulimit in order not to let the user space to pin all > + * available memory for TCE tables. > + */ > +static long kvmppc_account_memlimit(long npages) > +{ > + unsigned long ret = 0, locked, lock_limit; > + > + if (!current->mm) > + return -ESRCH; /* process exited */ > + > + down_write(¤t->mm->mmap_sem); > + locked = current->mm->locked_vm + npages; > + lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; > + if (locked > lock_limit && !capable(CAP_IPC_LOCK)) { > + pr_warn("RLIMIT_MEMLOCK (%ld) exceeded\n", > + rlimit(RLIMIT_MEMLOCK)); > + ret = -ENOMEM; > + } else { > + current->mm->locked_vm += npages; > + } > + up_write(¤t->mm->mmap_sem); > + > + return ret; > +} > + > static void release_spapr_tce_table(struct kvmppc_spapr_tce_table *stt) > { > struct kvm *kvm = stt->kvm; > int i; > + long npages = kvmppc_stt_npages(stt->window_size); > > mutex_lock(&kvm->lock); > list_del(&stt->list); > - for (i = 0; i < kvmppc_stt_npages(stt->window_size); i++) > + for (i = 0; i < npages; i++) > __free_page(stt->pages[i]); > + > kfree(stt); > mutex_unlock(&kvm->lock); > > + kvmppc_account_memlimit(-(npages + 1)); > + > kvm_put_kvm(kvm); > } > > @@ -112,6 +142,9 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, > } > > npages = kvmppc_stt_npages(args->window_size); > + ret = kvmppc_account_memlimit(npages + 1); > + if (ret) > + goto fail; This is called for VFIO only or is it also called when creating TCE tables for emulated devices ? Because in the latter case, you don't want to account the pages as locked, do you ? Also, you need to explain what +1 Finally, do I correctly deduce that creating 10 TCE tables of 2G each will end up accounting 20G as locked even if the guest for example only has 4G of RAM ? > stt = kzalloc(sizeof(*stt) + npages * sizeof(struct page *), > GFP_KERNEL); Ben.