linux-kernel - Re: [PATCH v2 0/2] khugepaged: collapse pmd for pte-mapped THP

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Message-ID: <20190801111945.t5jw3vivvfun4n27@box>
Date:   Thu, 1 Aug 2019 14:19:45 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Song Liu <songliubraving@...com>
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        akpm@...ux-foundation.org, matthew.wilcox@...cle.com,
        kirill.shutemov@...ux.intel.com, oleg@...hat.com,
        kernel-team@...com, william.kucharski@...cle.com,
        srikar@...ux.vnet.ibm.com
Subject: Re: [PATCH v2 0/2] khugepaged: collapse pmd for pte-mapped THP

On Wed, Jul 31, 2019 at 11:33:29AM -0700, Song Liu wrote:
> Changes v1 => v2:
> 1. Call collapse_pte_mapped_thp() directly from uprobe_write_opcode();
> 2. Add VM_BUG_ON() for addr alignment in khugepaged_add_pte_mapped_thp()
>    and collapse_pte_mapped_thp().
> 
> This set is the newer version of 5/6 and 6/6 of [1]. Newer version of
> 1-4 of the work [2] was recently picked by Andrew.
> 
> Patch 1 enables khugepaged to handle pte-mapped THP. These THPs are left
> in such state when khugepaged failed to get exclusive lock of mmap_sem.
> 
> Patch 2 leverages work in 1 for uprobe on THP. After [2], uprobe only
> splits the PMD. When the uprobe is disabled, we get pte-mapped THP.
> After this set, these pte-mapped THP will be collapsed as pmd-mapped.
> 
> [1] https://lkml.org/lkml/2019/6/23/23
> [2] https://www.spinics.net/lists/linux-mm/msg185889.html
> 
> Song Liu (2):
>   khugepaged: enable collapse pmd for pte-mapped THP
>   uprobe: collapse THP pmd after removing all uprobes

Looks good for the start.

Acked-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>

-- 
 Kirill A. Shutemov