From: Souptick Joarder <jrdr.linux@gmail.com>
To: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>,
Russell King - ARM Linux <linux@armlinux.org.uk>,
robin@protonic.nl, stefanr@s5r6.in-berlin.de, hjc@rock-chips.com,
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airlied@linux.ie, robin.murphy@arm.com, iamjoonsoo.kim@lge.com,
Andrew Morton <akpm@linux-foundation.org>,
Marek Szyprowski <m.szyprowski@samsung.com>,
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treding@nvidia.com, Michal Hocko <mhocko@suse.com>,
Dan Williams <dan.j.williams@intel.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
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Joe Perches <joe@perches.com>,
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Subject: Re: [PATCH v2] mm: Introduce new function vm_insert_kmem_page
Date: Fri, 5 Oct 2018 17:41:39 +0530 [thread overview]
Message-ID: <CAFqt6zYH4Aczu8AYke8AfGuMS70SJXCMn-n8X8C_Tz03gTjn8g@mail.gmail.com> (raw)
In-Reply-To: <CANiq72m9u1PL9X+dPNLxgkhvttj=4ijLyM2sFex=Kws7wswKzw@mail.gmail.com>
On Fri, Oct 5, 2018 at 4:19 PM Miguel Ojeda
<miguel.ojeda.sandonis@gmail.com> wrote:
>
> Hi Souptick,
>
> On Fri, Oct 5, 2018 at 12:01 PM Souptick Joarder <jrdr.linux@gmail.com> wrote:
> >
> > The final goal is to remove vm_insert_page by converting it to
> > vmf_insert_page. But to do that we have to first introduce the
> > new API which is similar to vm_insert_page (for non #PF). I tried this by
> > introducing vm_insert_kmem_page ( * identical as vm_insert_page
> > except API name *) in this patch. But this looks like a bad approach.
>
> We are going in circles here. That you want to convert vm_insert_page
> to vmf_insert_page for the PF case is fine and understood. However,
> you don't *need* to introduce a new name for the remaining non-PF
> cases if the function is going to be the exact same thing as before.
> You say "The final goal is to remove vm_insert_page", but you haven't
> justified *why* you need to remove that name.
>
> Now, if we want to rename the function for some reason (e.g. avoid
> confusion with vmf_insert_page), that is fine but is another topic. It
> may be or not a good idea, but it is orthogonal to the vmf_ work.
> Matthew, on this regard, told you that you shouldn't duplicate
> functions. If you want a rename, do so; but don't copy the code. In
> other words: nobody said introducing the vm_insert_kmem_page name is a
> bad idea -- what Matthew told you is that *duplicating* vm_insert_page
> just for that is bad.
>
> Further, you are copying the code (if I understand your thought
> process) because you want to change the callers of non-PF first, and
> then do the "full conversion from vm_* to vmf_*". However, that is
> confusing, because there is no need to change non-PF callers of
> vm_insert_page since they don't care about the new vmf_* functions.
>
> Instead, the proper way of doing this is:
>
> 1. Introduce the vmf_* API
> 2. Change all PF-users users to that (leaving all non-PF ones
> untouched!) -- if this is too big, you can split this patch into
> several patches, one per subsystem, etc.
We are done with step 2. All the PF-users are converted to use
vmf_insert_page. ( Ref - linux-next-20181005)
> 3. Remove the vm_* functions (except the ones that are still used in
> non-PF contexts, e.g. vm_insert_page)
Step 3 is part of step 2. Already done.
>
> Then, optionally, if you want to rename the function for the remaining
> non-PF users:
>
> 4. Rename vm_insert_page (justifying why the current name is
> confusing *on its own merits*).
>
> Otherwise, if you want to pursue Matthew's idea:
>
> 4. Introduce the vm_insert_range (possibly leveraging
> vm_insert_page, or not; you have to see what is best).
> 5. Replace those callers that can take advantage of vm_insert_range
> 6. Remove vm_insert_page and replace callers with vm_insert_range
> (only if it is not worth to keep vm_insert_range, again justifying it
> *on its own merits*)
Step 4 to 6, going to do it. It is part of plan now :-)
>
> As you see, these are all logical step-by-step improvements, without
> duplicating functions temporarily, leaving temporary changes or
> changing current callers to new APIs for unrelated reasons (i.e. no
> need to introduce vm_insert_kmem_page simply to do a "conversion" to
> vmf_).
>
> Cheers,
> Miguel
next prev parent reply other threads:[~2018-10-05 12:11 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-03 18:58 [PATCH v2] mm: Introduce new function vm_insert_kmem_page Souptick Joarder
2018-10-03 19:58 ` Miguel Ojeda
2018-10-04 11:56 ` Souptick Joarder
2018-10-03 20:00 ` Matthew Wilcox
2018-10-03 22:14 ` Russell King - ARM Linux
2018-10-04 0:39 ` Matthew Wilcox
2018-10-04 12:15 ` Souptick Joarder
2018-10-04 12:34 ` Russell King - ARM Linux
2018-10-04 18:12 ` Souptick Joarder
2018-10-04 18:17 ` Matthew Wilcox
2018-10-04 18:53 ` Souptick Joarder
2018-10-04 19:46 ` Miguel Ojeda
2018-10-05 5:50 ` Souptick Joarder
2018-10-05 8:52 ` Miguel Ojeda
2018-10-05 10:01 ` Souptick Joarder
2018-10-05 10:49 ` Miguel Ojeda
2018-10-05 12:11 ` Souptick Joarder [this message]
2018-10-05 18:09 ` Miguel Ojeda
2018-10-06 5:14 ` Souptick Joarder
2018-10-06 10:49 ` Miguel Ojeda
2018-10-23 12:14 ` Souptick Joarder
2018-10-23 12:24 ` Matthew Wilcox
2018-10-23 12:33 ` Souptick Joarder
2018-10-23 12:59 ` Matthew Wilcox
2018-10-23 13:15 ` Souptick Joarder
2018-10-04 18:21 ` Souptick Joarder
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