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From: Dave Hansen <dave.hansen@intel.com>
To: Reinette Chatre <reinette.chatre@intel.com>,
	Jarkko Sakkinen <jarkko@kernel.org>
Cc: dave.hansen@linux.intel.com, tglx@linutronix.de, bp@alien8.de,
	luto@kernel.org, mingo@redhat.com, linux-sgx@vger.kernel.org,
	x86@kernel.org, seanjc@google.com, kai.huang@intel.com,
	cathy.zhang@intel.com, cedric.xing@intel.com,
	haitao.huang@intel.com, mark.shanahan@intel.com, hpa@zytor.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH V3 19/30] x86/sgx: Free up EPC pages directly to support large page ranges
Date: Tue, 5 Apr 2022 10:25:15 -0700	[thread overview]
Message-ID: <f8d92685-27dd-e7ef-ce0d-100a285aec4b@intel.com> (raw)
In-Reply-To: <e118f4c6-7216-15f3-2bda-3a5851b0bcb1@intel.com>

On 4/5/22 10:13, Reinette Chatre wrote:
>>> +void sgx_direct_reclaim(void)
>>> +{
>>> +	if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
>>> +		sgx_reclaim_pages();
>>> +}
>> Please, instead open code this to both locations - not enough redundancy
>> to be worth of new function. Causes only unnecessary cross-referencing
>> when maintaining. Otherwise, I agree with the idea.
>>
> hmmm, that means the heart of the reclaimer (sgx_reclaim_pages()) would be
> made available for direct use from everywhere in the driver. I will look into this.

I like the change.  It's not about reducing code redundancy, it's about
*describing* what the code does.  Each location could have:

	/* Enter direct SGX reclaim: */
	if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
		sgx_reclaim_pages();

Or, it could just be:

	sgx_direct_reclaim();

Which also provides a logical choke point to add comments, like:

/*
 * sgx_direct_reclaim() should be called in locations where SGX
 * memory resources might be low and might be needed in order
 * to make forward progress.
 */
void sgx_direct_reclaim(void)
{
	...

  reply	other threads:[~2022-04-06  0:26 UTC|newest]

Thread overview: 79+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-04 16:49 [PATCH V3 00/30] x86/sgx and selftests/sgx: Support SGX2 Reinette Chatre
2022-04-04 16:49 ` [PATCH V3 01/30] x86/sgx: Add short descriptions to ENCLS wrappers Reinette Chatre
2022-04-05  6:52   ` Jarkko Sakkinen
2022-04-04 16:49 ` [PATCH V3 02/30] x86/sgx: Add wrapper for SGX2 EMODPR function Reinette Chatre
2022-04-05  6:53   ` Jarkko Sakkinen
2022-04-04 16:49 ` [PATCH V3 03/30] x86/sgx: Add wrapper for SGX2 EMODT function Reinette Chatre
2022-04-05  6:53   ` Jarkko Sakkinen
2022-04-04 16:49 ` [PATCH V3 04/30] x86/sgx: Add wrapper for SGX2 EAUG function Reinette Chatre
2022-04-05  6:54   ` Jarkko Sakkinen
2022-04-04 16:49 ` [PATCH V3 05/30] x86/sgx: Support loading enclave page without VMA permissions check Reinette Chatre
2022-04-05  6:56   ` Jarkko Sakkinen
2022-04-04 16:49 ` [PATCH V3 06/30] x86/sgx: Export sgx_encl_ewb_cpumask() Reinette Chatre
2022-04-05  6:56   ` Jarkko Sakkinen
2022-04-04 16:49 ` [PATCH V3 07/30] x86/sgx: Rename sgx_encl_ewb_cpumask() as sgx_encl_cpumask() Reinette Chatre
2022-04-05  6:57   ` Jarkko Sakkinen
2022-04-04 16:49 ` [PATCH V3 08/30] x86/sgx: Move PTE zap code to new sgx_zap_enclave_ptes() Reinette Chatre
2022-04-05  6:59   ` Jarkko Sakkinen
2022-04-04 16:49 ` [PATCH V3 09/30] x86/sgx: Make sgx_ipi_cb() available internally Reinette Chatre
2022-04-05  6:59   ` Jarkko Sakkinen
2022-04-04 16:49 ` [PATCH V3 10/30] x86/sgx: Create utility to validate user provided offset and length Reinette Chatre
2022-04-05  7:00   ` Jarkko Sakkinen
2022-04-04 16:49 ` [PATCH V3 11/30] x86/sgx: Keep record of SGX page type Reinette Chatre
2022-04-05  7:00   ` Jarkko Sakkinen
2022-04-04 16:49 ` [PATCH V3 12/30] x86/sgx: Export sgx_encl_{grow,shrink}() Reinette Chatre
2022-04-05  7:04   ` Jarkko Sakkinen
2022-04-04 16:49 ` [PATCH V3 13/30] x86/sgx: Export sgx_encl_page_alloc() Reinette Chatre
2022-04-04 16:49 ` [PATCH V3 14/30] x86/sgx: Support restricting of enclave page permissions Reinette Chatre
2022-04-05  5:03   ` Jarkko Sakkinen
2022-04-05  5:07     ` Jarkko Sakkinen
2022-04-05 13:40       ` Jarkko Sakkinen
2022-04-05 14:19         ` Jarkko Sakkinen
2022-04-05 14:27           ` Jarkko Sakkinen
2022-04-05 14:52             ` Jarkko Sakkinen
2022-04-05 16:49               ` Reinette Chatre
2022-04-05 18:39                 ` Jarkko Sakkinen
2022-04-05 18:59                   ` Reinette Chatre
2022-04-06  7:30                     ` Jarkko Sakkinen
2022-04-06 17:51                       ` Reinette Chatre
2022-04-05 16:40             ` Reinette Chatre
2022-04-04 16:49 ` [PATCH V3 15/30] x86/sgx: Support adding of pages to an initialized enclave Reinette Chatre
2022-04-05  5:05   ` Jarkko Sakkinen
2022-04-05 10:03     ` Jarkko Sakkinen
2022-04-06  7:37       ` Jarkko Sakkinen
2022-04-06 22:42         ` Reinette Chatre
2022-04-04 16:49 ` [PATCH V3 16/30] x86/sgx: Tighten accessible memory range after enclave initialization Reinette Chatre
2022-04-05  7:05   ` Jarkko Sakkinen
2022-04-04 16:49 ` [PATCH V3 17/30] x86/sgx: Support modifying SGX page type Reinette Chatre
2022-04-05  7:06   ` Jarkko Sakkinen
2022-04-05 15:34     ` Jarkko Sakkinen
2022-04-05 17:05       ` Reinette Chatre
2022-04-05 18:41         ` Jarkko Sakkinen
2022-04-05 18:59           ` Reinette Chatre
2022-04-06  7:32             ` Jarkko Sakkinen
2022-04-06 17:50               ` Reinette Chatre
2022-04-04 16:49 ` [PATCH V3 18/30] x86/sgx: Support complete page removal Reinette Chatre
2022-04-05  7:08   ` Jarkko Sakkinen
2022-04-04 16:49 ` [PATCH V3 19/30] x86/sgx: Free up EPC pages directly to support large page ranges Reinette Chatre
2022-04-05  7:11   ` Jarkko Sakkinen
2022-04-05 17:13     ` Reinette Chatre
2022-04-05 17:25       ` Dave Hansen [this message]
2022-04-06  6:35         ` Jarkko Sakkinen
2022-04-06 17:50           ` Reinette Chatre
2022-04-05 18:42       ` Jarkko Sakkinen
2022-04-05 19:56         ` Reinette Chatre
2022-04-04 16:49 ` [PATCH V3 20/30] Documentation/x86: Introduce enclave runtime management section Reinette Chatre
2022-04-04 16:49 ` [PATCH V3 21/30] selftests/sgx: Add test for EPCM permission changes Reinette Chatre
2022-04-05  7:02   ` Jarkko Sakkinen
2022-04-05  7:03     ` Jarkko Sakkinen
2022-04-05 17:28     ` Reinette Chatre
2022-04-05 18:43       ` Jarkko Sakkinen
2022-04-04 16:49 ` [PATCH V3 22/30] selftests/sgx: Add test for TCS page " Reinette Chatre
2022-04-04 16:49 ` [PATCH V3 23/30] selftests/sgx: Test two different SGX2 EAUG flows Reinette Chatre
2022-04-04 16:49 ` [PATCH V3 24/30] selftests/sgx: Introduce dynamic entry point Reinette Chatre
2022-04-04 16:49 ` [PATCH V3 25/30] selftests/sgx: Introduce TCS initialization enclave operation Reinette Chatre
2022-04-04 16:49 ` [PATCH V3 26/30] selftests/sgx: Test complete changing of page type flow Reinette Chatre
2022-04-04 16:49 ` [PATCH V3 27/30] selftests/sgx: Test faulty enclave behavior Reinette Chatre
2022-04-04 16:49 ` [PATCH V3 28/30] selftests/sgx: Test invalid access to removed enclave page Reinette Chatre
2022-04-04 16:49 ` [PATCH V3 29/30] selftests/sgx: Test reclaiming of untouched page Reinette Chatre
2022-04-04 16:49 ` [PATCH V3 30/30] selftests/sgx: Page removal stress test Reinette Chatre

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