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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, linux-sgx@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Jethro Beekman <jethro@fortanix.com>,
	Jordan Hand <jorhand@linux.microsoft.com>,
	Nathaniel McCallum <npmccallum@redhat.com>,
	Chunyang Hui <sanqian.hcy@antfin.com>,
	Seth Moore <sethmo@google.com>,
	akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com,
	asapek@google.com, cedric.xing@intel.com,
	chenalexchen@google.com, conradparker@google.com,
	cyhanish@google.com, dave.hansen@intel.com,
	haitao.huang@intel.com, josh@joshtriplett.org,
	kai.huang@intel.com, kai.svahn@intel.com, kmoy@google.com,
	ludloff@google.com, luto@kernel.org, nhorman@redhat.com,
	puiterwijk@redhat.com, rientjes@google.com, tglx@linutronix.de,
	yaozhangx@google.com
Subject: Re: [PATCH v38 16/24] x86/sgx: Add a page reclaimer
Date: Tue, 29 Sep 2020 01:35:28 -0700	[thread overview]
Message-ID: <20200929083528.GN353@linux.intel.com> (raw)
In-Reply-To: <20200929035010.GB301037@linux.intel.com>

On Tue, Sep 29, 2020 at 06:50:10AM +0300, Jarkko Sakkinen wrote:
> On Mon, Sep 28, 2020 at 06:14:39PM -0700, Sean Christopherson wrote:
> > On Tue, Sep 22, 2020 at 05:03:23PM +0300, Jarkko Sakkinen wrote:
> > > On Tue, Sep 22, 2020 at 12:45:38PM +0200, Borislav Petkov wrote:
> > > > > +	spin_lock(&sgx_active_page_list_lock);
> > > > > +	for (i = 0; i < SGX_NR_TO_SCAN; i++) {
> > > > > +		if (list_empty(&sgx_active_page_list))
> > > > 
> > > > Isn't it enough to do this once, i.e., not in the loop? You're holding
> > > > sgx_active_page_list_lock...
> > 
> > Argh, I missed this until I looked at Jarkko's updated tree.
> > 
> > The reason for checking list_empty() on every iteration is that the loop is
> > greedy, i.e. it tries to grab and reclaim up to 16 (SGX_NR_TO_SCAN) EPC pages
> > at a time.
> > 
> > > I think that would make sense. Distantly analogous to the EINIT
> > > discussion. Too complex code for yet to be known problem workloads I'd
> > > say.
> > 
> > Nooooo.  Please no.
> 
> I added this comment in the beginning of the sgx_reclaim_pages() based
> on your response:
> 
> /*
>  * Take a fixed number of pages from the head of the active page pool and
>  * reclaim them to the enclave's private shmem files. Skip the pages, which have
>  * been accessed since the last scan. Move those pages to the tail of active
>  * page pool so that the pages get scanned in LRU like fashion.
>  *
>  * Batch process a chunk of pages (at the moment 16) in order to degrade amount
>  * of IPI's and ETRACK's potentially required. sgx_encl_ewb() does degrade a bit
>  * among the HW threads with three stage EWB pipeline (EWB, ETRACK + EWB and IPI
>  * + EWB) but not sufficiently. Reclaiming one page at a time would also be
>  * problematic as it would increase the lock contention too much, which would
>  * halt forward progress.
>  */
> 
> And reverted reclaimer patch as it was. Do you have anything in mind
> that I should add or modify in it?

Nope, can't think of anything.

  reply	other threads:[~2020-09-29  8:35 UTC|newest]

Thread overview: 187+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-15 11:28 [PATCH v38 00/24] Intel SGX foundations Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 01/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 02/24] x86/cpufeatures: x86/msr: Add Intel SGX Launch Control " Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 03/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-09-16 11:44   ` Borislav Petkov
2020-09-16 20:30     ` Jarkko Sakkinen
2020-09-16 20:32       ` Borislav Petkov
2020-09-15 11:28 ` [PATCH v38 04/24] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 05/24] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 06/24] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 07/24] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 08/24] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 09/24] x86/sgx: Add __sgx_alloc_epc_page() and sgx_free_epc_page() Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 10/24] mm: Add vm_ops->mprotect() Jarkko Sakkinen
2020-09-18 12:44   ` Borislav Petkov
2020-09-18 15:09   ` Andy Lutomirski
2020-09-18 23:24     ` [PATCH v38 10/24] mm: Add vm_ops->mprotect()' Jarkko Sakkinen
2020-09-18 23:53     ` [PATCH v38 10/24] mm: Add vm_ops->mprotect() Sean Christopherson
2020-09-19  0:15       ` Andy Lutomirski
2020-09-22 12:58         ` Jarkko Sakkinen
2020-09-22 15:11           ` Dave Hansen
2020-09-23 13:30             ` Jarkko Sakkinen
2020-09-23 13:43             ` Jarkko Sakkinen
2020-09-23 14:33             ` Jarkko Sakkinen
2020-09-24 14:50               ` Dave Hansen
2020-09-24 16:27                 ` Sean Christopherson
2020-09-24 19:35                 ` Jarkko Sakkinen
2020-09-21 12:49       ` Jarkko Sakkinen
2020-09-21 12:51         ` Jarkko Sakkinen
2020-09-21 13:14         ` Jarkko Sakkinen
2020-09-21 16:57         ` Sean Christopherson
2020-09-21 21:07           ` Jarkko Sakkinen
2020-09-21 21:18             ` Sean Christopherson
2020-09-22  5:29               ` Jarkko Sakkinen
2020-09-22  5:35                 ` Jarkko Sakkinen
2020-09-22 16:43                   ` Sean Christopherson
2020-09-23 13:50                     ` Jarkko Sakkinen
2020-09-24 19:11                       ` Haitao Huang
2020-09-24 19:28                         ` Sean Christopherson
2020-09-24 19:39                           ` Dave Hansen
2020-09-24 20:01                             ` Sean Christopherson
2020-09-24 20:10                               ` Dave Hansen
2020-09-24 20:25                                 ` Sean Christopherson
2020-09-24 20:54                                   ` Dave Hansen
2020-09-24 22:10                                     ` Jarkko Sakkinen
2020-09-24 23:05                                     ` Sean Christopherson
2020-09-24 23:09                                       ` Dave Hansen
2020-09-25  0:00                                         ` Sean Christopherson
2020-09-25 17:18                                           ` Dave Hansen
2020-09-25 19:43                                             ` Sean Christopherson
2020-09-25 19:53                                               ` Dave Hansen
2020-09-26  4:15                                                 ` Andy Lutomirski
2020-09-28  0:53                                                 ` Jarkko Sakkinen
2020-09-28 14:04                                                   ` Dave Hansen
2020-09-28 16:19                                                     ` Jarkko Sakkinen
2020-09-28 16:48                                                       ` Dave Hansen
2020-09-28 19:32                                                         ` Jarkko Sakkinen
2020-09-28 19:45                                                           ` Dave Hansen
2020-09-28 20:19                                                             ` Jarkko Sakkinen
2020-09-29  1:37                                                               ` Andy Lutomirski
2020-09-29  4:05                                                                 ` Jarkko Sakkinen
2020-09-29 14:24                                                                   ` Dave Hansen
2020-09-30  0:20                                                                     ` Jarkko Sakkinen
2020-09-30 14:35                                                                       ` Dave Hansen
2020-09-28 20:18                                                         ` Jarkko Sakkinen
2020-10-18  8:49                                                     ` Dr. Greg
2020-10-19 21:31                                                       ` Sean Christopherson
2020-10-20 10:01                                                         ` Dr. Greg
2020-10-20 16:40                                                           ` Sean Christopherson
2020-10-24 14:37                                                             ` Dr. Greg
2020-10-24 15:33                                                               ` Andy Lutomirski
2020-10-26 10:51                                                                 ` Dr. Greg
2020-10-26 22:59                                                                   ` Andy Lutomirski
2020-10-27  0:40                                                                     ` Sean Christopherson
2020-09-24 22:07                                 ` Jarkko Sakkinen
2020-09-24 21:58                           ` Jarkko Sakkinen
2020-09-24 21:55                         ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 11/24] x86/sgx: Add SGX enclave driver Jarkko Sakkinen
2020-09-21  9:30   ` Borislav Petkov
2020-09-21 12:09     ` Jarkko Sakkinen
2020-10-01 17:36   ` Sean Christopherson
2020-10-01 18:49     ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 12/24] x86/sgx: Add SGX_IOC_ENCLAVE_CREATE Jarkko Sakkinen
2020-09-21 10:03   ` Borislav Petkov
2020-09-21 12:28     ` Jarkko Sakkinen
2020-09-21 13:51       ` Borislav Petkov
2020-09-21 19:29         ` Jarkko Sakkinen
2020-10-03  0:23   ` Haitao Huang
2020-10-03  3:24     ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 14/24] x86/sgx: Add SGX_IOC_ENCLAVE_INIT Jarkko Sakkinen
2020-09-21 17:35   ` Borislav Petkov
2020-09-21 18:10     ` Sean Christopherson
2020-09-21 18:27       ` Borislav Petkov
     [not found]         ` <20200921191658.GA24823@linux.intel.com>
2020-09-22  8:29           ` Borislav Petkov
2020-09-22 11:50             ` Jarkko Sakkinen
2020-09-22 12:56             ` Jethro Beekman
2020-09-22 14:29               ` Borislav Petkov
2020-09-23 14:47                 ` Jarkko Sakkinen
2020-09-23 15:55                   ` Borislav Petkov
2020-09-24 12:23                     ` Jarkko Sakkinen
2020-09-22 16:29               ` Sean Christopherson
2020-09-21 19:22       ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 15/24] x86/sgx: Enable provisioning for remote attestation Jarkko Sakkinen
2020-09-21 18:07   ` Borislav Petkov
2020-09-21 19:27     ` Jarkko Sakkinen
2020-09-21 19:41       ` Borislav Petkov
2020-09-21 21:26         ` Jarkko Sakkinen
2020-09-22  8:30           ` Borislav Petkov
2020-09-15 11:28 ` [PATCH v38 16/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-09-22 10:45   ` Borislav Petkov
2020-09-22 14:03     ` Jarkko Sakkinen
2020-09-22 14:24       ` Borislav Petkov
2020-09-23 14:52         ` Jarkko Sakkinen
2020-09-29  1:14       ` Sean Christopherson
2020-09-29  3:50         ` Jarkko Sakkinen
2020-09-29  8:35           ` Sean Christopherson [this message]
2020-09-22 16:24     ` Sean Christopherson
2020-09-22 18:02       ` Borislav Petkov
2020-09-23 15:25       ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 17/24] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2020-09-22 15:44   ` Borislav Petkov
2020-09-23 13:20     ` Jarkko Sakkinen
2020-09-23 16:17       ` Borislav Petkov
2020-09-24 11:51         ` Jarkko Sakkinen
2020-09-24 15:57           ` Borislav Petkov
2020-09-24 20:38             ` [PATCH v38 17/24] x86/sgx: ptrace() support for the SGX driver' Jarkko Sakkinen
2020-09-24 20:40               ` Jarkko Sakkinen
2020-09-25  7:53                 ` Borislav Petkov
2020-09-25 11:00                   ` Jarkko Sakkinen
2020-09-25  7:51               ` Borislav Petkov
2020-09-25 11:21                 ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 18/24] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-09-23 22:07   ` Borislav Petkov
2020-09-24 12:09     ` Jarkko Sakkinen
2020-09-24 16:00       ` Borislav Petkov
2020-09-24 21:07         ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 19/24] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 20/24] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-09-24 16:31   ` Borislav Petkov
2020-09-24 23:11     ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-09-24 18:04   ` Borislav Petkov
2020-09-25  1:00     ` Jarkko Sakkinen
2020-09-25  8:28       ` Borislav Petkov
2020-09-27 23:37         ` Jarkko Sakkinen
2020-09-28  8:30           ` Borislav Petkov
2020-09-28 15:02             ` Jarkko Sakkinen
2020-09-25  8:39       ` Jethro Beekman
2020-09-25 11:17         ` Jarkko Sakkinen
2020-09-25 11:43           ` Jethro Beekman
     [not found]     ` <20200925003808.GB20333@linux.intel.com>
2020-09-25  1:04       ` Jarkko Sakkinen
2020-09-25  8:14       ` Borislav Petkov
2020-09-25 10:59         ` Jarkko Sakkinen
2020-09-28 14:36       ` Jarkko Sakkinen
2020-09-25 18:23   ` Andrew Cooper
2020-09-28  0:58     ` Jarkko Sakkinen
2020-09-28 16:44       ` Andrew Cooper
2020-09-28 18:07         ` H.J. Lu
2020-09-28 18:12           ` Andy Lutomirski
2020-09-28 18:17             ` Dave Hansen
2020-09-28 22:07               ` Jarkko Sakkinen
2020-09-28 21:56             ` Jarkko Sakkinen
2020-09-28 22:06               ` H.J. Lu
2020-09-28 22:18                 ` Dave Hansen
2020-09-28 22:41                   ` Andy Lutomirski
2020-09-28 23:38                     ` Andrew Cooper
2020-09-29 14:10                       ` Dave Hansen
2020-09-29 15:01                         ` Andrew Cooper
2020-09-28 21:41           ` Jarkko Sakkinen
2020-09-28 20:42         ` Jarkko Sakkinen
2020-09-28 23:52           ` Andrew Cooper
2020-09-30  0:52             ` Jarkko Sakkinen
2020-09-28 15:43     ` Yu, Yu-cheng
2020-09-28 15:54       ` H.J. Lu
2020-09-28 16:40         ` Yu, Yu-cheng
2020-09-28 21:36         ` Jarkko Sakkinen
2020-09-28 20:56       ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 22/24] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 23/24] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-09-23 13:50   ` Borislav Petkov
2020-09-24 11:28     ` Jarkko Sakkinen
2020-09-24 15:54       ` Borislav Petkov
2020-09-15 11:28 ` [PATCH v38 24/24] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2020-09-25 22:37   ` Sean Christopherson
2020-09-28  0:44     ` Jarkko Sakkinen
  -- strict thread matches above, loose matches on Subject: below --
2020-09-15 11:04 [PATCH v38 00/24] Intel SGX foundations Jarkko Sakkinen
2020-09-15 11:05 ` [PATCH v38 16/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen

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