From: David Miller <davem@davemloft.net>
To: joel@joelfernandes.org
Cc: linux-mips@linux-mips.org, linux-ia64@vger.kernel.org,
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linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 2/2] mm: speed up mremap by 500x on large regions
Date: Fri, 12 Oct 2018 11:18:36 -0700 (PDT) [thread overview]
Message-ID: <20181012.111836.1569129998592378186.davem@davemloft.net> (raw)
In-Reply-To: <20181012125046.GA170912@joelaf.mtv.corp.google.com>
From: Joel Fernandes <joel@joelfernandes.org>
Date: Fri, 12 Oct 2018 05:50:46 -0700
> If its an issue, then how do transparent huge pages work on Sparc? I don't
> see the huge page code (move_huge_pages) during mremap doing anything special
> for Sparc architecture when moving PMDs..
This is because all huge pages are larger than SHMLBA. So no cache flushing
necessary.
> 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.
next prev parent reply other threads:[~2018-10-12 18:20 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 [this message]
2018-10-13 1:35 ` Joel Fernandes
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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