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Date:   Tue, 26 Jul 2022 16:33:18 +0200
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Subject: Re: [PATCHv7 03/14] mm: Report unaccepted memory in meminfo
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To:     "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Borislav Petkov <bp@alien8.de>,
        Andy Lutomirski <luto@kernel.org>,
        Sean Christopherson <seanjc@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Joerg Roedel <jroedel@suse.de>,
        Ard Biesheuvel <ardb@kernel.org>
Cc:     Andi Kleen <ak@linux.intel.com>,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        David Rientjes <rientjes@google.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Ingo Molnar <mingo@redhat.com>,
        Varad Gautam <varad.gautam@suse.com>,
        Dario Faggioli <dfaggioli@suse.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Mike Rapoport <rppt@kernel.org>, marcelo.cerri@canonical.com,
        tim.gardner@canonical.com, khalid.elmously@canonical.com,
        philip.cox@canonical.com, x86@kernel.org, linux-mm@kvack.org,
        linux-coco@lists.linux.dev, linux-efi@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20220614120231.48165-1-kirill.shutemov@linux.intel.com>
 <20220614120231.48165-4-kirill.shutemov@linux.intel.com>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
In-Reply-To: <20220614120231.48165-4-kirill.shutemov@linux.intel.com>
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On 14.06.22 14:02, Kirill A. Shutemov wrote:
> Track amount of unaccepted memory and report it in /proc/meminfo and in
> node meminfo.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
>  drivers/base/node.c    | 7 +++++++
>  fs/proc/meminfo.c      | 5 +++++
>  include/linux/mmzone.h | 1 +
>  mm/page_alloc.c        | 9 ++++++++-
>  mm/vmstat.c            | 1 +
>  5 files changed, 22 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/base/node.c b/drivers/base/node.c
> index 0ac6376ef7a1..fc7cf4d91eb6 100644
> --- a/drivers/base/node.c
> +++ b/drivers/base/node.c
> @@ -446,6 +446,9 @@ static ssize_t node_read_meminfo(struct device *dev,
>  			     "Node %d ShmemPmdMapped: %8lu kB\n"
>  			     "Node %d FileHugePages: %8lu kB\n"
>  			     "Node %d FilePmdMapped: %8lu kB\n"
> +#endif
> +#ifdef CONFIG_UNACCEPTED_MEMORY
> +			     "Node %d UnacceptedPages: %8lu kB\n"

Nit: I'd just call that "Unaccepted", as the unit is kB.

>  #endif
>  			     ,
>  			     nid, K(node_page_state(pgdat, NR_FILE_DIRTY)),
> @@ -474,6 +477,10 @@ static ssize_t node_read_meminfo(struct device *dev,
>  			     nid, K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)),
>  			     nid, K(node_page_state(pgdat, NR_FILE_THPS)),
>  			     nid, K(node_page_state(pgdat, NR_FILE_PMDMAPPED))
> +#endif
> +#ifdef CONFIG_UNACCEPTED_MEMORY
> +			     ,
> +			     nid, K(node_page_state(pgdat, NR_UNACCEPTED))
>  #endif
>  			    );
>  	len += hugetlb_report_node_meminfo(buf, len, nid);
> diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
> index 6e89f0e2fd20..796544e50365 100644
> --- a/fs/proc/meminfo.c
> +++ b/fs/proc/meminfo.c
> @@ -153,6 +153,11 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
>  		    global_zone_page_state(NR_FREE_CMA_PAGES));
>  #endif
>  
> +#ifdef CONFIG_UNACCEPTED_MEMORY
> +	show_val_kb(m, "UnacceptedPages:",
> +		    global_node_page_state(NR_UNACCEPTED));

Dito.

> +#endif
> +
>  	hugetlb_report_meminfo(m);
>  
>  	arch_report_meminfo(m);
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index aab70355d64f..aa08cd7eaaf5 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -212,6 +212,7 @@ enum node_stat_item {
>  	NR_FOLL_PIN_ACQUIRED,	/* via: pin_user_page(), gup flag: FOLL_PIN */
>  	NR_FOLL_PIN_RELEASED,	/* pages returned via unpin_user_page() */
>  	NR_KERNEL_STACK_KB,	/* measured in KiB */
> +	NR_UNACCEPTED,

Do we want to ifdef that as well? (and in all other cases below)

>  #if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
>  	NR_KERNEL_SCS_KB,	/* measured in KiB */
>  #endif
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 279c2746aaa8..6316d695a567 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -1012,6 +1012,7 @@ static void accept_page(struct page *page, unsigned int order)
>  
>  	accept_memory(start, start + (PAGE_SIZE << order));
>  	__ClearPageUnaccepted(page);
> +	mod_node_page_state(page_pgdat(page), NR_UNACCEPTED, -(1 << order));
>  
>  	/* Assert that there is no PageUnaccepted() on tail pages */
>  	if (IS_ENABLED(CONFIG_DEBUG_VM)) {
> @@ -1063,6 +1064,7 @@ static inline void __free_one_page(struct page *page,
>  	struct page *buddy;
>  	bool to_tail;
>  	bool page_needs_acceptance = false;
> +	int nr_unaccepted = 0;
>  
>  	VM_BUG_ON(!zone_is_initialized(zone));
>  	VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page);
> @@ -1076,6 +1078,7 @@ static inline void __free_one_page(struct page *page,
>  
>  	if (PageUnaccepted(page)) {
>  		page_needs_acceptance = true;
> +		nr_unaccepted += 1 << order;
>  		__ClearPageUnaccepted(page);
>  	}
>  
> @@ -1117,6 +1120,7 @@ static inline void __free_one_page(struct page *page,
>  		/* Mark page unaccepted if any of merged pages were unaccepted */
>  		if (PageUnaccepted(buddy)) {
>  			page_needs_acceptance = true;
> +			nr_unaccepted += 1 << order;
>  			__ClearPageUnaccepted(buddy);
>  		}
>  
> @@ -1143,8 +1147,11 @@ static inline void __free_one_page(struct page *page,
>  	 */
>  	if (!page_needs_acceptance && (fpi_flags & FPI_UNACCEPTED_SLOWPATH))
>  		page_needs_acceptance = page_contains_unaccepted(page, order);
> -	if (page_needs_acceptance)
> +	if (page_needs_acceptance) {
>  		__SetPageUnaccepted(page);
> +		__mod_node_page_state(page_pgdat(page), NR_UNACCEPTED,
> +				    (1 << order) - nr_unaccepted);
> +	}
>  
>  	if (fpi_flags & FPI_TO_TAIL)
>  		to_tail = true;
> diff --git a/mm/vmstat.c b/mm/vmstat.c
> index 373d2730fcf2..4e12d22f1e04 100644
> --- a/mm/vmstat.c
> +++ b/mm/vmstat.c
> @@ -1236,6 +1236,7 @@ const char * const vmstat_text[] = {
>  	"nr_foll_pin_acquired",
>  	"nr_foll_pin_released",
>  	"nr_kernel_stack",
> +	"nr_unaccepted",
>  #if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
>  	"nr_shadow_call_stack",
>  #endif


LGTM

-- 
Thanks,

David / dhildenb