From: Joel Fernandes <joel@joelfernandes.org>
To: David Miller <davem@davemloft.net>
Cc: kirill@shutemov.name, linux-kernel@vger.kernel.org,
kernel-team@android.com, minchan@kernel.org, pantin@google.com,
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richard@nod.at
Subject: Re: [PATCH v2 2/2] mm: speed up mremap by 500x on large regions
Date: Fri, 12 Oct 2018 18:35:40 -0700 [thread overview]
Message-ID: <20181013013540.GA207108@joelaf.mtv.corp.google.com> (raw)
In-Reply-To: <20181012.111836.1569129998592378186.davem@davemloft.net>
On Fri, Oct 12, 2018 at 11:18:36AM -0700, David Miller wrote:
> From: Joel Fernandes <joel@joelfernandes.org>
[...]
> > Also, do we not flush the caches from any path when we munmap
> > address space? We do call do_munmap on the old mapping from mremap
> > after moving to the new one.
>
> Sparc makes sure that shared mapping have consistent colors. Therefore
> all that's left are private mappings and those will be initialized by
> block stores to clear the page out or similar.
>
> Also, when creating new mappings, we flush the D-cache when necessary
> in update_mmu_cache().
>
> We also maintain a bit in the page struct to track when a page which
> was potentially written to on one cpu ends up mapped into another
> address space and flush as necessary.
>
> The cache is write-through, which simplifies the preconditions we have
> to maintain.
Makes sense, thanks. For the moment I sent patches to enable this on arm64
and x86. We can enable it on sparc as well at a later time as it sounds it
could be a safe optimization to apply to that architecture as well.
thanks,
- Joel
next prev parent reply other threads:[~2018-10-13 1:35 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-12 1:37 [PATCH v2 1/2] treewide: remove unused address argument from pte_alloc functions Joel Fernandes (Google)
2018-10-12 1:37 ` [PATCH v2 2/2] mm: speed up mremap by 500x on large regions Joel Fernandes (Google)
2018-10-12 11:30 ` Kirill A. Shutemov
2018-10-12 11:36 ` Kirill A. Shutemov
2018-10-12 12:50 ` Joel Fernandes
2018-10-12 13:19 ` Kirill A. Shutemov
2018-10-12 16:57 ` Joel Fernandes
2018-10-12 21:33 ` Kirill A. Shutemov
2018-10-12 18:18 ` David Miller
2018-10-13 1:35 ` Joel Fernandes [this message]
2018-10-13 1:39 ` Daniel Colascione
2018-10-13 1:44 ` Joel Fernandes
2018-10-13 1:54 ` Daniel Colascione
2018-10-13 2:10 ` Joel Fernandes
2018-10-13 2:25 ` Daniel Colascione
2018-10-13 17:50 ` Joel Fernandes
2018-10-12 18:02 ` David Miller
2018-10-12 14:09 ` Anton Ivanov
2018-10-12 14:37 ` Kirill A. Shutemov
2018-10-12 14:48 ` Anton Ivanov
2018-10-12 16:42 ` Anton Ivanov
2018-10-12 16:50 ` Joel Fernandes
2018-10-12 16:58 ` Anton Ivanov
2018-10-12 17:06 ` Joel Fernandes
2018-10-12 21:40 ` Kirill A. Shutemov
2018-10-13 6:10 ` Anton Ivanov
2018-10-15 7:10 ` Christian Borntraeger
2018-10-15 8:18 ` Martin Schwidefsky
2018-10-16 2:08 ` Joel Fernandes
2018-10-12 11:09 ` [PATCH v2 1/2] treewide: remove unused address argument from pte_alloc functions Kirill A. Shutemov
2018-10-12 16:37 ` Joel Fernandes
2018-10-12 13:56 ` Anton Ivanov
2018-10-12 16:34 ` Joel Fernandes
2018-10-12 16:38 ` Julia Lawall
2018-10-12 16:46 ` Joel Fernandes
2018-10-12 18:51 ` SF Markus Elfring
2018-10-12 19:42 ` Joel Fernandes
2018-10-13 9:22 ` SF Markus Elfring
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