From: "Jarkko Sakkinen" <jarkko@kernel.org>
To: "Haitao Huang" <haitao.huang@linux.intel.com>,
<dave.hansen@linux.intel.com>, <tj@kernel.org>,
<mkoutny@suse.com>, <linux-kernel@vger.kernel.org>,
<linux-sgx@vger.kernel.org>, <x86@kernel.org>,
<cgroups@vger.kernel.org>, <tglx@linutronix.de>,
<mingo@redhat.com>, <bp@alien8.de>, <hpa@zytor.com>,
<sohil.mehta@intel.com>
Cc: <zhiquan1.li@intel.com>, <kristen@linux.intel.com>,
<seanjc@google.com>, <zhanb@microsoft.com>,
<anakrish@microsoft.com>, <mikko.ylinen@linux.intel.com>,
<yangjie@microsoft.com>, <chrisyan@microsoft.com>
Subject: Re: [PATCH v8 07/15] x86/sgx: Expose sgx_reclaim_pages() for cgroup
Date: Fri, 02 Feb 2024 01:37:44 +0200 [thread overview]
Message-ID: <CYU4Z2HB9QTM.27NW3GSTRPXCM@suppilovahvero> (raw)
In-Reply-To: <20240130020938.10025-8-haitao.huang@linux.intel.com>
On Tue Jan 30, 2024 at 4:09 AM EET, Haitao Huang wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
>
> Each EPC cgroup will have an LRU structure to track reclaimable EPC pages.
> When a cgroup usage reaches its limit, the cgroup needs to reclaim pages
> from its LRU or LRUs of its descendants to make room for any new
> allocations.
>
> To prepare for reclamation per cgroup, expose the top level reclamation
> function, sgx_reclaim_pages(), in header file for reuse. Add a parameter
> to the function to pass in an LRU so cgroups can pass in different
> tracking LRUs later. Add another parameter for passing in the number of
> pages to scan and make the function return the number of pages reclaimed
> as a cgroup reclaimer may need to track reclamation progress from its
> descendants, change number of pages to scan in subsequent calls.
>
> Create a wrapper for the global reclaimer, sgx_reclaim_pages_global(),
> to just call this function with the global LRU passed in. When
> per-cgroup LRU is added later, the wrapper will perform global
> reclamation from the root cgroup.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Co-developed-by: Kristen Carlson Accardi <kristen@linux.intel.com>
> Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
> Co-developed-by: Haitao Huang <haitao.huang@linux.intel.com>
> Signed-off-by: Haitao Huang <haitao.huang@linux.intel.com>
> ---
> V8:
> - Use width of 80 characters in text paragraphs. (Jarkko)
>
> V7:
> - Reworked from patch 9 of V6, "x86/sgx: Restructure top-level EPC reclaim
> function". Do not split the top level function (Kai)
> - Dropped patches 7 and 8 of V6.
> ---
> arch/x86/kernel/cpu/sgx/main.c | 53 +++++++++++++++++++++++-----------
> arch/x86/kernel/cpu/sgx/sgx.h | 1 +
> 2 files changed, 37 insertions(+), 17 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index a131aa985c95..4f5824c4751d 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -286,11 +286,13 @@ static void sgx_reclaimer_write(struct sgx_epc_page *epc_page,
> mutex_unlock(&encl->lock);
> }
>
> -/*
> - * 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.
> +/**
> + * sgx_reclaim_pages() - Reclaim a fixed number of pages from an LRU
> + *
> + * Take a fixed number of pages from the head of a given LRU 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 the list 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
> @@ -298,8 +300,13 @@ static void sgx_reclaimer_write(struct sgx_epc_page *epc_page,
> * + 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.
> + *
> + * @lru: The LRU from which pages are reclaimed.
> + * @nr_to_scan: Pointer to the target number of pages to scan, must be less than
> + * SGX_NR_TO_SCAN.
> + * Return: Number of pages reclaimed.
> */
> -static void sgx_reclaim_pages(void)
> +unsigned int sgx_reclaim_pages(struct sgx_epc_lru_list *lru, unsigned int *nr_to_scan)
> {
> struct sgx_epc_page *chunk[SGX_NR_TO_SCAN];
> struct sgx_backing backing[SGX_NR_TO_SCAN];
> @@ -310,10 +317,10 @@ static void sgx_reclaim_pages(void)
> int ret;
> int i;
>
> - spin_lock(&sgx_global_lru.lock);
> - for (i = 0; i < SGX_NR_TO_SCAN; i++) {
> - epc_page = list_first_entry_or_null(&sgx_global_lru.reclaimable,
> - struct sgx_epc_page, list);
> + spin_lock(&lru->lock);
> +
> + for (; *nr_to_scan > 0; --(*nr_to_scan)) {
> + epc_page = list_first_entry_or_null(&lru->reclaimable, struct sgx_epc_page, list);
> if (!epc_page)
> break;
>
> @@ -328,7 +335,8 @@ static void sgx_reclaim_pages(void)
> */
> epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
> }
> - spin_unlock(&sgx_global_lru.lock);
> +
> + spin_unlock(&lru->lock);
>
> for (i = 0; i < cnt; i++) {
> epc_page = chunk[i];
> @@ -351,9 +359,9 @@ static void sgx_reclaim_pages(void)
> continue;
>
> skip:
> - spin_lock(&sgx_global_lru.lock);
> - list_add_tail(&epc_page->list, &sgx_global_lru.reclaimable);
> - spin_unlock(&sgx_global_lru.lock);
> + spin_lock(&lru->lock);
> + list_add_tail(&epc_page->list, &lru->reclaimable);
> + spin_unlock(&lru->lock);
>
> kref_put(&encl_page->encl->refcount, sgx_encl_release);
>
> @@ -366,6 +374,7 @@ static void sgx_reclaim_pages(void)
> sgx_reclaimer_block(epc_page);
> }
>
> + ret = 0;
> for (i = 0; i < cnt; i++) {
> epc_page = chunk[i];
> if (!epc_page)
> @@ -378,7 +387,10 @@ static void sgx_reclaim_pages(void)
> epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
>
> sgx_free_epc_page(epc_page);
> + ret++;
> }
> +
> + return (unsigned int)ret;
> }
>
> static bool sgx_should_reclaim(unsigned long watermark)
> @@ -387,6 +399,13 @@ static bool sgx_should_reclaim(unsigned long watermark)
> !list_empty(&sgx_global_lru.reclaimable);
> }
>
> +static void sgx_reclaim_pages_global(void)
> +{
> + unsigned int nr_to_scan = SGX_NR_TO_SCAN;
> +
> + sgx_reclaim_pages(&sgx_global_lru, &nr_to_scan);
> +}
> +
> /*
> * sgx_reclaim_direct() should be called (without enclave's mutex held)
> * in locations where SGX memory resources might be low and might be
> @@ -395,7 +414,7 @@ static bool sgx_should_reclaim(unsigned long watermark)
> void sgx_reclaim_direct(void)
> {
> if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
> - sgx_reclaim_pages();
> + sgx_reclaim_pages_global();
> }
>
> static int ksgxd(void *p)
> @@ -418,7 +437,7 @@ static int ksgxd(void *p)
> sgx_should_reclaim(SGX_NR_HIGH_PAGES));
>
> if (sgx_should_reclaim(SGX_NR_HIGH_PAGES))
> - sgx_reclaim_pages();
> + sgx_reclaim_pages_global();
>
> cond_resched();
> }
> @@ -604,7 +623,7 @@ struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim)
> * Need to do a global reclamation if cgroup was not full but free
> * physical pages run out, causing __sgx_alloc_epc_page() to fail.
> */
> - sgx_reclaim_pages();
> + sgx_reclaim_pages_global();
> cond_resched();
> }
>
> diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
> index 0e99e9ae3a67..2593c013d091 100644
> --- a/arch/x86/kernel/cpu/sgx/sgx.h
> +++ b/arch/x86/kernel/cpu/sgx/sgx.h
> @@ -110,6 +110,7 @@ void sgx_reclaim_direct(void);
> void sgx_mark_page_reclaimable(struct sgx_epc_page *page);
> int sgx_unmark_page_reclaimable(struct sgx_epc_page *page);
> struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim);
> +unsigned int sgx_reclaim_pages(struct sgx_epc_lru_list *lru, unsigned int *nr_to_scan);
>
> void sgx_ipi_cb(void *info);
>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
BR, Jarkko
next prev parent reply other threads:[~2024-02-01 23:37 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-30 2:09 [PATCH v8 00/15] Add Cgroup support for SGX EPC memory Haitao Huang
2024-01-30 2:09 ` [PATCH v8 01/15] cgroup/misc: Add per resource callbacks for CSS events Haitao Huang
2024-02-01 23:24 ` Jarkko Sakkinen
2024-02-02 16:34 ` Haitao Huang
2024-02-02 17:02 ` Tejun Heo
2024-02-12 19:31 ` Jarkko Sakkinen
2024-01-30 2:09 ` [PATCH v8 02/15] cgroup/misc: Export APIs for SGX driver Haitao Huang
2024-01-30 2:09 ` [PATCH v8 03/15] cgroup/misc: Add SGX EPC resource type Haitao Huang
2024-01-30 2:09 ` [PATCH v8 04/15] x86/sgx: Implement basic EPC misc cgroup functionality Haitao Huang
2024-01-30 15:22 ` Huang, Kai
2024-01-31 1:59 ` Haitao Huang
2024-02-01 23:27 ` Jarkko Sakkinen
2024-01-30 2:09 ` [PATCH v8 05/15] x86/sgx: Add sgx_epc_lru_list to encapsulate LRU list Haitao Huang
2024-02-01 23:28 ` Jarkko Sakkinen
2024-02-02 16:52 ` Haitao Huang
2024-01-30 2:09 ` [PATCH v8 06/15] x86/sgx: Abstract tracking reclaimable pages in LRU Haitao Huang
2024-02-01 23:29 ` Jarkko Sakkinen
2024-01-30 2:09 ` [PATCH v8 07/15] x86/sgx: Expose sgx_reclaim_pages() for cgroup Haitao Huang
2024-01-30 15:39 ` Huang, Kai
2024-01-31 1:35 ` Haitao Huang
2024-02-01 23:37 ` Jarkko Sakkinen [this message]
2024-01-30 2:09 ` [PATCH v8 08/15] x86/sgx: Implement EPC reclamation flows " Haitao Huang
2024-02-01 23:39 ` Jarkko Sakkinen
2024-01-30 2:09 ` [PATCH v8 09/15] x86/sgx: Charge mem_cgroup for per-cgroup reclamation Haitao Huang
2024-01-30 2:09 ` [PATCH v8 10/15] x86/sgx: Add EPC reclamation in cgroup try_charge() Haitao Huang
2024-01-30 2:09 ` [PATCH v8 11/15] x86/sgx: Abstract check for global reclaimable pages Haitao Huang
2024-01-30 2:09 ` [PATCH v8 12/15] x86/sgx: Expose sgx_epc_cgroup_reclaim_pages() for global reclaimer Haitao Huang
2024-01-30 2:09 ` [PATCH v8 13/15] x86/sgx: Turn on per-cgroup EPC reclamation Haitao Huang
2024-01-30 2:09 ` [PATCH v8 14/15] Docs/x86/sgx: Add description for cgroup support Haitao Huang
2024-01-30 2:09 ` [PATCH v8 15/15] selftests/sgx: Add scripts for EPC cgroup testing Haitao Huang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CYU4Z2HB9QTM.27NW3GSTRPXCM@suppilovahvero \
--to=jarkko@kernel.org \
--cc=anakrish@microsoft.com \
--cc=bp@alien8.de \
--cc=cgroups@vger.kernel.org \
--cc=chrisyan@microsoft.com \
--cc=dave.hansen@linux.intel.com \
--cc=haitao.huang@linux.intel.com \
--cc=hpa@zytor.com \
--cc=kristen@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-sgx@vger.kernel.org \
--cc=mikko.ylinen@linux.intel.com \
--cc=mingo@redhat.com \
--cc=mkoutny@suse.com \
--cc=seanjc@google.com \
--cc=sohil.mehta@intel.com \
--cc=tglx@linutronix.de \
--cc=tj@kernel.org \
--cc=x86@kernel.org \
--cc=yangjie@microsoft.com \
--cc=zhanb@microsoft.com \
--cc=zhiquan1.li@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).