linux-kernel - Re: [PATCH 1/1] mm/madvise: enhance lazyfreeing with mTHP in madvise

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]

Date: Mon, 26 Feb 2024 13:04:11 +0000
From: Ryan Roberts <ryan.roberts@....com>
To: Lance Yang <ioworker0@...il.com>, David Hildenbrand <david@...hat.com>
Cc: 21cnbao@...il.com, akpm@...ux-foundation.org,
 linux-kernel@...r.kernel.org, linux-mm@...ck.org, mhocko@...e.com,
 minchan@...nel.org, peterx@...hat.com, shy828301@...il.com,
 songmuchun@...edance.com, wangkefeng.wang@...wei.com, zokeefe@...gle.com,
 fengwei.yin@...el.com
Subject: Re: [PATCH 1/1] mm/madvise: enhance lazyfreeing with mTHP in
 madvise_free

On 26/02/2024 08:55, Lance Yang wrote:
> Hey David,
> 
> Thanks for your suggestion!
> 
> On Mon, Feb 26, 2024 at 4:41 PM David Hildenbrand <david@...hat.com> wrote:
>>
> [...]
>>> On Mon, Feb 26, 2024 at 12:00 PM Barry Song <21cnbao@...il.com> wrote:
>>> [...]
>>>> On Mon, Feb 26, 2024 at 1:33 AM Lance Yang <ioworker0@...il.com> wrote:
>>> [...]
> [...]
>>> +static inline bool pte_range_cont_mapped(pte_t *pte, unsigned long nr)
>>> +{
>>> +     pte_t pte_val;
>>> +     unsigned long pfn = pte_pfn(pte);
>>> +     for (int i = 0; i < nr; i++) {
>>> +             pte_val = ptep_get(pte + i);
>>> +             if (pte_none(pte_val) || pte_pfn(pte_val) != (pfn + i))
>>> +                     return false;
>>> +     }
>>> +     return true;
>>> +}
>>
>> I dislike the "cont mapped" terminology.
>>
>> Maybe folio_pte_batch() does what you want?
> 
> folio_pte_batch() is a good choice. Appreciate it!

Agreed, folio_pte_batch() is likely to be widely useful for this change and
others, so suggest exporting it from memory.c and reusing as is if possible.

> 
> Best,
> Lance
> 
>>
>> --
>> Cheers,
>>
>> David / dhildenb
>>