linux-kernel - Re: [RFC] mm/vmstat: Add events for HugeTLB migration

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200925094912.GA31664@linux>
Date:   Fri, 25 Sep 2020 11:49:16 +0200
From:   Oscar Salvador <osalvador@...e.de>
To:     Anshuman Khandual <anshuman.khandual@....com>
Cc:     linux-mm@...ck.org, Daniel Jordan <daniel.m.jordan@...cle.com>,
        Zi Yan <ziy@...dia.com>, John Hubbard <jhubbard@...dia.com>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC] mm/vmstat: Add events for HugeTLB migration

On Fri, Sep 25, 2020 at 02:42:29PM +0530, Anshuman Khandual wrote:
> Add following new vmstat events which will track HugeTLB page migration.
> 
> 1. HUGETLB_MIGRATION_SUCCESS
> 2. HUGETLB_MIGRATION_FAILURE
> 
> It follows the existing semantics to accommodate HugeTLB subpages in total
> page migration statistics. While here, this updates current trace event
> "mm_migrate_pages" to accommodate now available HugeTLB based statistics.
> 
> Cc: Daniel Jordan <daniel.m.jordan@...cle.com>
> Cc: Zi Yan <ziy@...dia.com>
> Cc: John Hubbard <jhubbard@...dia.com>
> Cc: Mike Kravetz <mike.kravetz@...cle.com>
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Cc: linux-mm@...ck.org
> Cc: linux-kernel@...r.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>

Was this inspired by some usecase/debugging or just to follow THP's example?

>  	int retry = 1;
>  	int thp_retry = 1;
> +	int hugetlb_retry = 1;
>  	int nr_failed = 0;
>  	int nr_succeeded = 0;
>  	int nr_thp_succeeded = 0;
>  	int nr_thp_failed = 0;
>  	int nr_thp_split = 0;
> +	int nr_hugetlb_succeeded = 0;
> +	int nr_hugetlb_failed = 0;
>  	int pass = 0;
>  	bool is_thp = false;
> +	bool is_hugetlb = false;
>  	struct page *page;
>  	struct page *page2;
>  	int swapwrite = current->flags & PF_SWAPWRITE;
> @@ -1433,6 +1437,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
>  	for (pass = 0; pass < 10 && (retry || thp_retry); pass++) {

Should you not have put hugetlb_retry within the loop as well?
Otherwise we might not rety for hugetlb pages now?

-- 
Oscar Salvador
SUSE L3