From: Jason Gunthorpe <jgg@nvidia.com>
To: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: akpm@linux-foundation.org, tglx@linutronix.de,
kirill.shutemov@linux.intel.com, mika.penttila@nextfour.com,
david@redhat.com, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
songmuchun@bytedance.com, zhouchengming@bytedance.com
Subject: Re: [PATCH v3 02/15] mm: introduce is_huge_pmd() helper
Date: Wed, 10 Nov 2021 08:59:36 -0400 [thread overview]
Message-ID: <20211110125936.GR1740502@nvidia.com> (raw)
In-Reply-To: <18fa08bf-847b-1c47-10ee-01c92caeb0cc@bytedance.com>
On Wed, Nov 10, 2021 at 08:58:35PM +0800, Qi Zheng wrote:
>
> On 11/10/21 8:29 PM, Jason Gunthorpe wrote:
> > On Wed, Nov 10, 2021 at 04:40:44PM +0800, Qi Zheng wrote:
> > > Currently we have some times the following judgments repeated in the
> > > code:
> > >
> > > is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)
> > >
> > > which is to determine whether the *pmd is a huge pmd, so introduce
> > > is_huge_pmd() helper to deduplicate them.
> >
> > Isn't this pmd_leaf() ?
>
> Currently, the implementation of pmd_leaf() does not include
> pmd_devmap() checks.
Are you sure? I thought x86 did via the tricky bit checks?
> But considering the semantics of pmd_leaf(), the "devmap" pmd should
> also belong to "leaf" pmd. Maybe we should modify pmd_leaf() to make
> it more semantically consistent?
I would prefer that..
Jason
next prev parent reply other threads:[~2021-11-10 12:59 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-10 8:40 [PATCH v3 00/15] Free user PTE page table pages Qi Zheng
2021-11-10 8:40 ` [PATCH v3 01/15] mm: do code cleanups to filemap_map_pmd() Qi Zheng
2021-11-10 8:40 ` [PATCH v3 02/15] mm: introduce is_huge_pmd() helper Qi Zheng
2021-11-10 12:29 ` Jason Gunthorpe
2021-11-10 12:58 ` Qi Zheng
2021-11-10 12:59 ` Jason Gunthorpe [this message]
2021-11-10 8:40 ` [PATCH v3 03/15] mm: move pte_offset_map_lock() to pgtable.h Qi Zheng
2021-11-10 8:40 ` [PATCH v3 04/15] mm: rework the parameter of lock_page_or_retry() Qi Zheng
2021-11-10 8:40 ` [PATCH v3 05/15] mm: add pmd_installed_type return for __pte_alloc() and other friends Qi Zheng
2021-11-10 8:40 ` [PATCH v3 06/15] mm: introduce refcount for user PTE page table page Qi Zheng
2021-11-10 8:40 ` [PATCH v3 07/15] mm/pte_ref: add support for user PTE page table page allocation Qi Zheng
2021-11-10 8:40 ` [PATCH v3 08/15] mm/pte_ref: initialize the refcount of the withdrawn PTE page table page Qi Zheng
2021-11-10 8:40 ` [PATCH v3 09/15] mm/pte_ref: add support for the map/unmap of user " Qi Zheng
2021-11-10 8:52 ` [PATCH v3 00/15] Free user PTE page table pages Qi Zheng
2021-11-10 10:54 Qi Zheng
2021-11-10 10:54 ` [PATCH v3 02/15] mm: introduce is_huge_pmd() helper Qi Zheng
2021-11-11 13:46 ` kernel test robot
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