From: Suren Baghdasaryan <surenb@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: michel@lespinasse.org, jglisse@google.com, mhocko@suse.com,
vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net,
dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com,
peterz@infradead.org, ldufour@linux.ibm.com, paulmck@kernel.org,
mingo@redhat.com, will@kernel.org, luto@kernel.org,
songliubraving@fb.com, peterx@redhat.com, david@redhat.com,
dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de,
kent.overstreet@linux.dev, punit.agrawal@bytedance.com,
lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com,
axelrasmussen@google.com, joelaf@google.com, minchan@google.com,
jannh@google.com, shakeelb@google.com, tatashin@google.com,
edumazet@google.com, gthelen@google.com, gurua@google.com,
arjunroy@google.com, soheil@google.com, hughlynch@google.com,
leewalsh@google.com, posk@google.com, linux-mm@kvack.org,
linux-arm-kernel@lists.infradead.org,
linuxppc-dev@lists.ozlabs.org, x86@kernel.org,
linux-kernel@vger.kernel.org, kernel-team@android.com
Subject: Re: [PATCH v3 2/7] mm: introduce vma->vm_flags wrapper functions
Date: Wed, 25 Jan 2023 16:56:17 -0800 [thread overview]
Message-ID: <CAJuCfpFWTNpz7LB+931Gc+yYwBq3-y+_doH2WdtjhTGnxLxvig@mail.gmail.com> (raw)
In-Reply-To: <20230125162810.ec222773d13cd26c55991fde@linux-foundation.org>
On Wed, Jan 25, 2023 at 4:28 PM Andrew Morton <akpm@linux-foundation.org> wrote:
>
> On Wed, 25 Jan 2023 15:35:49 -0800 Suren Baghdasaryan <surenb@google.com> wrote:
>
> > --- a/include/linux/mm_types.h
> > +++ b/include/linux/mm_types.h
> > @@ -491,7 +491,15 @@ struct vm_area_struct {
> > * See vmf_insert_mixed_prot() for discussion.
> > */
> > pgprot_t vm_page_prot;
> > - unsigned long vm_flags; /* Flags, see mm.h. */
> > +
> > + /*
> > + * Flags, see mm.h.
> > + * To modify use {init|reset|set|clear|mod}_vm_flags() functions.
> > + */
> > + union {
> > + const vm_flags_t vm_flags;
> > + vm_flags_t __private __vm_flags;
> > + };
>
> Typically when making a change like this we'll rename the affected
> field/variable/function/etc. This will reliably and deliberately break
> unconverted usage sites.
>
> This const trick will get us partway there, by breaking setters. But
> renaming it will break both setters and getters.
My intent here is to break setters but to allow getters to keep
reading vma->vm_flags directly. We could provide get_vm_flags() and
convert all getters as well but it would introduce a huge additional
churn (800+ hits) with no obvious benefits, I think. Does that clarify
the intent of this trick?
>
> --
> To unsubscribe from this group and stop receiving emails from it, send an email to kernel-team+unsubscribe@android.com.
>
next prev parent reply other threads:[~2023-01-26 0:56 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-25 23:35 [PATCH v3 0/7] introduce vm_flags modifier functions Suren Baghdasaryan
2023-01-25 23:35 ` [PATCH v3 1/7] kernel/fork: convert vma assignment to a memcpy Suren Baghdasaryan
2023-01-26 0:21 ` Andrew Morton
2023-01-26 0:50 ` Suren Baghdasaryan
2023-01-26 1:34 ` Andrew Morton
2023-01-26 11:52 ` Mel Gorman
2023-01-26 15:59 ` Suren Baghdasaryan
2023-01-26 17:27 ` Paul E. McKenney
2023-02-07 17:16 ` Marco Elver
2023-02-07 17:23 ` Suren Baghdasaryan
2023-02-07 17:51 ` Marco Elver
2023-01-25 23:35 ` [PATCH v3 2/7] mm: introduce vma->vm_flags wrapper functions Suren Baghdasaryan
2023-01-26 0:24 ` Andrew Morton
2023-01-26 0:51 ` Suren Baghdasaryan
2023-01-26 17:48 ` Davidlohr Bueso
2023-01-26 0:28 ` Andrew Morton
2023-01-26 0:56 ` Suren Baghdasaryan [this message]
2023-01-26 7:59 ` Michal Hocko
2023-01-26 8:33 ` Michal Hocko
2023-01-26 13:58 ` Mel Gorman
2023-01-26 16:01 ` Suren Baghdasaryan
2023-01-25 23:35 ` [PATCH v3 3/7] mm: replace VM_LOCKED_CLEAR_MASK with VM_LOCKED_MASK Suren Baghdasaryan
2023-01-26 13:59 ` Mel Gorman
2023-01-26 14:16 ` Mel Gorman
2023-01-25 23:35 ` [PATCH v3 4/7] mm: replace vma->vm_flags direct modifications with modifier calls Suren Baghdasaryan
2023-01-26 15:10 ` Mel Gorman
2023-01-26 16:10 ` Suren Baghdasaryan
2023-01-26 17:26 ` Mel Gorman
2023-01-26 17:28 ` Suren Baghdasaryan
2023-01-25 23:35 ` [PATCH v3 5/7] mm: replace vma->vm_flags indirect modification in ksm_madvise Suren Baghdasaryan
2023-01-26 15:19 ` Mel Gorman
2023-01-26 16:11 ` Suren Baghdasaryan
2023-01-25 23:35 ` [PATCH v3 6/7] mm: introduce mod_vm_flags_nolock and use it in untrack_pfn Suren Baghdasaryan
2023-01-26 8:34 ` Michal Hocko
2023-01-26 15:47 ` Mel Gorman
2023-01-26 16:18 ` Suren Baghdasaryan
2023-01-26 17:32 ` Mel Gorman
2023-01-26 17:34 ` Suren Baghdasaryan
2023-01-25 23:35 ` [PATCH v3 7/7] mm: export dump_mm() Suren Baghdasaryan
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