From: Peter Zijlstra <peterz@infradead.org>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Steve Capper <steve.capper@linaro.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux@arm.linux.org.uk" <linux@arm.linux.org.uk>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
"gary.robertson@linaro.org" <gary.robertson@linaro.org>,
"anders.roxell@linaro.org" <anders.roxell@linaro.org>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>
Subject: Re: [RFC PATCH V4 6/7] arm64: mm: Enable HAVE_RCU_TABLE_FREE logic
Date: Thu, 1 May 2014 11:57:39 +0200 [thread overview]
Message-ID: <20140501095739.GO11096@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20140501095246.GB22316@arm.com>
On Thu, May 01, 2014 at 10:52:47AM +0100, Catalin Marinas wrote:
> Does gup_fast walking increment the mm_users? Or is it a requirement of
> the calling code? I can't seem to find where this happens.
No, its not required at all. One should only walk current->mm with
gup_fast, any other usage is broken.
And by delaying TLB shootdown, either through disabling IRQs and
stalling IPIs or by using RCU freeing, you're guaranteed your own page
tables won't disappear underneath your feet.
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next prev parent reply other threads:[~2014-05-01 9:57 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-28 15:01 [RFC PATCH V4 0/7] get_user_pages_fast for ARM and ARM64 Steve Capper
2014-03-28 15:01 ` [RFC PATCH V4 1/7] mm: Introduce a general RCU get_user_pages_fast Steve Capper
2014-03-28 15:01 ` [RFC PATCH V4 2/7] arm: mm: Introduce special ptes for LPAE Steve Capper
2014-03-28 15:01 ` [RFC PATCH V4 3/7] arm: mm: Enable HAVE_RCU_TABLE_FREE logic Steve Capper
2014-05-01 11:11 ` Catalin Marinas
2014-05-01 11:44 ` Steve Capper
2014-03-28 15:01 ` [RFC PATCH V4 4/7] arm: mm: Enable RCU fast_gup Steve Capper
2014-03-28 15:01 ` [RFC PATCH V4 5/7] arm64: Convert asm/tlb.h to generic mmu_gather Steve Capper
2014-03-28 15:01 ` [RFC PATCH V4 6/7] arm64: mm: Enable HAVE_RCU_TABLE_FREE logic Steve Capper
2014-04-30 15:20 ` Catalin Marinas
2014-04-30 15:33 ` Catalin Marinas
2014-04-30 15:38 ` Steve Capper
2014-04-30 17:21 ` Catalin Marinas
2014-05-01 7:34 ` Steve Capper
2014-05-01 9:52 ` Catalin Marinas
2014-05-01 9:57 ` Peter Zijlstra [this message]
2014-05-01 10:04 ` Catalin Marinas
2014-05-01 10:15 ` Steve Capper
2014-03-28 15:01 ` [RFC PATCH V4 7/7] arm64: mm: Enable RCU fast_gup Steve Capper
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