From: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com> To: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com>, linux-arm-kernel <linux-arm-kernel@lists.infradead.org>, linux-kernel <linux-kernel@vger.kernel.org>, Xinwei Hu <huxinwei@huawei.com>, Zefan Li <lizefan@huawei.com>, Hanjun Guo <guohanjun@huawei.com>, Tianhong Ding <dingtianhong@huawei.com>, Steve Capper <Steve.Capper@arm.com>, David Woods <dwoods@ezchip.com> Subject: Re: [PATCH 1/1] arm64/hugetlb: clear PG_dcache_clean if the page is dirty when munmap Date: Fri, 8 Jul 2016 11:36:57 +0800 [thread overview] Message-ID: <577F1FD9.1040205@huawei.com> (raw) In-Reply-To: <20160707153741.GC27180@e104818-lin.cambridge.arm.com> On 2016/7/7 23:37, Catalin Marinas wrote: > On Thu, Jul 07, 2016 at 08:09:04PM +0800, Zhen Lei wrote: >> At present, PG_dcache_clean is only cleared when the related huge page >> is about to be freed. But sometimes, there maybe a process is in charge >> to copy binary codes into a shared memory, and notifies other processes >> to execute base on that. For the first time, there is no problem, because >> the default value of page->flags is PG_dcache_clean cleared. So the cache >> will be maintained at the time of set_pte_at for other processes. But if >> the content of the shared memory have been updated again, there is no >> cache operations, because the PG_dcache_clean is still set. >> >> For example: >> Process A >> open a hugetlbfs file >> mmap it as a shared memory >> copy some binary codes into it >> munmap >> >> Process B >> open the hugetlbfs file >> mmap it as a shared memory, executable >> invoke the functions in the shared memory >> munmap >> >> repeat the above steps. > > Does this work as you would expect with small pages (and for example > shared file mmap)? I don't want to have a different behaviour between > small and huge pages. The small pages also have this problem, I will try to fix it too. >
WARNING: multiple messages have this Message-ID (diff)
From: thunder.leizhen@huawei.com (Leizhen (ThunderTown)) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 1/1] arm64/hugetlb: clear PG_dcache_clean if the page is dirty when munmap Date: Fri, 8 Jul 2016 11:36:57 +0800 [thread overview] Message-ID: <577F1FD9.1040205@huawei.com> (raw) In-Reply-To: <20160707153741.GC27180@e104818-lin.cambridge.arm.com> On 2016/7/7 23:37, Catalin Marinas wrote: > On Thu, Jul 07, 2016 at 08:09:04PM +0800, Zhen Lei wrote: >> At present, PG_dcache_clean is only cleared when the related huge page >> is about to be freed. But sometimes, there maybe a process is in charge >> to copy binary codes into a shared memory, and notifies other processes >> to execute base on that. For the first time, there is no problem, because >> the default value of page->flags is PG_dcache_clean cleared. So the cache >> will be maintained at the time of set_pte_at for other processes. But if >> the content of the shared memory have been updated again, there is no >> cache operations, because the PG_dcache_clean is still set. >> >> For example: >> Process A >> open a hugetlbfs file >> mmap it as a shared memory >> copy some binary codes into it >> munmap >> >> Process B >> open the hugetlbfs file >> mmap it as a shared memory, executable >> invoke the functions in the shared memory >> munmap >> >> repeat the above steps. > > Does this work as you would expect with small pages (and for example > shared file mmap)? I don't want to have a different behaviour between > small and huge pages. The small pages also have this problem, I will try to fix it too. >
next prev parent reply other threads:[~2016-07-08 3:38 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-07-07 12:09 [PATCH 1/1] arm64/hugetlb: clear PG_dcache_clean if the page is dirty when munmap Zhen Lei 2016-07-07 12:09 ` Zhen Lei 2016-07-07 15:37 ` Catalin Marinas 2016-07-07 15:37 ` Catalin Marinas 2016-07-08 3:36 ` Leizhen (ThunderTown) [this message] 2016-07-08 3:36 ` Leizhen (ThunderTown) 2016-07-08 13:54 ` Catalin Marinas 2016-07-08 13:54 ` Catalin Marinas 2016-07-08 15:24 ` Leizhen (ThunderTown) 2016-07-08 15:24 ` Leizhen (ThunderTown) 2016-07-08 16:13 ` Catalin Marinas 2016-07-08 16:13 ` Catalin Marinas 2016-07-11 12:43 ` Leizhen (ThunderTown) 2016-07-11 12:43 ` Leizhen (ThunderTown) 2016-07-12 15:35 ` Catalin Marinas 2016-07-12 15:35 ` Catalin Marinas 2016-07-20 2:46 ` Leizhen (ThunderTown) 2016-07-20 2:46 ` Leizhen (ThunderTown) 2016-07-20 9:19 ` Catalin Marinas 2016-07-20 9:19 ` Catalin Marinas 2016-08-22 4:19 ` Leizhen (ThunderTown) 2016-08-22 4:19 ` Leizhen (ThunderTown) 2016-08-23 17:28 ` Catalin Marinas 2016-08-23 17:28 ` Catalin Marinas 2016-08-24 1:30 ` Leizhen (ThunderTown) 2016-08-24 1:30 ` Leizhen (ThunderTown) 2016-08-24 9:00 ` Leizhen (ThunderTown) 2016-08-24 9:00 ` Leizhen (ThunderTown) 2016-08-24 10:30 ` Catalin Marinas 2016-08-24 10:30 ` Catalin Marinas 2016-08-25 1:42 ` Leizhen (ThunderTown) 2016-08-25 1:42 ` Leizhen (ThunderTown) 2016-08-25 9:30 ` Catalin Marinas 2016-08-25 9:30 ` Catalin Marinas 2016-08-25 11:27 ` Leizhen (ThunderTown) 2016-08-25 11:27 ` Leizhen (ThunderTown)
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