From: Nicholas Piggin <npiggin@gmail.com>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [RFC REBASED 5/5] powerpc/mm/slice: use the dynamic high slice size to limit bitmap operations
Date: Tue, 27 Feb 2018 19:11:25 +1000 [thread overview]
Message-ID: <20180227191125.659d5cbe@roar.ozlabs.ibm.com> (raw)
In-Reply-To: <87bmga7qng.fsf@linux.vnet.ibm.com>
On Tue, 27 Feb 2018 14:31:07 +0530
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote:
> Christophe Leroy <christophe.leroy@c-s.fr> writes:
>
> > The number of high slices a process might use now depends on its
> > address space size, and what allocation address it has requested.
> >
> > This patch uses that limit throughout call chains where possible,
> > rather than use the fixed SLICE_NUM_HIGH for bitmap operations.
> > This saves some cost for processes that don't use very large address
> > spaces.
>
> I haven't really looked at the final code. One of the issue we had was
> with the below scenario.
>
> mmap(addr, len) where addr < 128TB and addr+len > 128TB We want to make
> sure we build the mask such that we don't find the addr available.
We should run it through the mmap regression tests. I *think* we moved
all of that logic from the slice code to get_ummapped_area before going
in to slices. I may have missed something though, it would be good to
have more eyes on it.
Thanks,
Nick
next prev parent reply other threads:[~2018-02-27 9:11 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-12 18:12 [RFC REBASED 1/5] powerpc/mm/slice: pass pointers to struct slice_mask where possible Christophe Leroy
2018-02-12 18:12 ` [RFC REBASED 2/5] powerpc/mm/slice: implement a slice mask cache Christophe Leroy
2018-02-12 18:12 ` [RFC REBASED 3/5] powerpc/mm/slice: implement slice_check_range_fits Christophe Leroy
2018-02-27 7:20 ` Aneesh Kumar K.V
2018-02-27 9:04 ` Nicholas Piggin
2018-02-12 18:12 ` [RFC REBASED 4/5] powerpc/mm/slice: Use const pointers to cached slice masks where possible Christophe Leroy
2018-02-27 7:29 ` Aneesh Kumar K.V
2018-02-27 9:08 ` Nicholas Piggin
2018-02-12 18:12 ` [RFC REBASED 5/5] powerpc/mm/slice: use the dynamic high slice size to limit bitmap operations Christophe Leroy
2018-02-27 9:01 ` Aneesh Kumar K.V
2018-02-27 9:11 ` Nicholas Piggin [this message]
2018-02-27 12:41 ` Aneesh Kumar K.V
2018-02-28 6:53 ` Nicholas Piggin
2018-02-28 6:59 ` Aneesh Kumar K.V
2018-03-01 7:09 ` Christophe LEROY
2018-03-01 9:22 ` Nicholas Piggin
2018-02-28 7:07 ` Aneesh Kumar K.V
[not found] ` <87muzu7w58.fsf@linux.vnet.ibm.com>
2018-02-27 7:04 ` [RFC REBASED 1/5] powerpc/mm/slice: pass pointers to struct slice_mask where possible Christophe LEROY
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