From: toshi.kani@hpe.com (Kani, Toshi)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 2/2] x86/mm: implement free pmd/pte page interfaces
Date: Sat, 28 Apr 2018 20:54:42 +0000 [thread overview]
Message-ID: <1524948829.2693.547.camel@hpe.com> (raw)
In-Reply-To: <20180428090217.n2l3w4vobmtkvz6k@8bytes.org>
On Sat, 2018-04-28 at 11:02 +0200, joro at 8bytes.org wrote:
> On Fri, Apr 27, 2018 at 02:31:51PM +0000, Kani, Toshi wrote:
> > So, we can add the step 2 on top of this patch.
> > 1. Clear pud/pmd entry.
> > 2. System wide TLB flush <-- TO BE ADDED BY NEW PATCH
> > 3. Free its underlining pmd/pte page.
>
> This still lacks the page-table synchronization and will thus not fix
> the BUG_ON being triggered.
The BUG_ON issue is specific to PAE that it syncs at the pmd level.
x86/64 does not have this issue since it syncs at the pgd or p4d level.
> > We do not need to revert this patch. We can make the above change I
> > mentioned.
>
> Please note that we are not in the merge window anymore and that any fix
> needs to be simple and obviously correct.
Understood. Changing the x86/32 sync point is risky. So, I am going to
revert the free page handling for PAE.
Thanks,
-Toshi
WARNING: multiple messages have this Message-ID (diff)
From: "Kani, Toshi" <toshi.kani@hpe.com>
To: "joro@8bytes.org" <joro@8bytes.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"bp@suse.de" <bp@suse.de>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"guohanjun@huawei.com" <guohanjun@huawei.com>,
"wxf.wang@hisilicon.com" <wxf.wang@hisilicon.com>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"willy@infradead.org" <willy@infradead.org>,
"hpa@zytor.com" <hpa@zytor.com>,
"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
"mingo@redhat.com" <mingo@redhat.com>,
"will.deacon@arm.com" <will.deacon@arm.com>,
"Hocko, Michal" <MHocko@suse.com>,
"cpandya@codeaurora.org" <cpandya@codeaurora.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v2 2/2] x86/mm: implement free pmd/pte page interfaces
Date: Sat, 28 Apr 2018 20:54:42 +0000 [thread overview]
Message-ID: <1524948829.2693.547.camel@hpe.com> (raw)
In-Reply-To: <20180428090217.n2l3w4vobmtkvz6k@8bytes.org>
On Sat, 2018-04-28 at 11:02 +0200, joro@8bytes.org wrote:
> On Fri, Apr 27, 2018 at 02:31:51PM +0000, Kani, Toshi wrote:
> > So, we can add the step 2 on top of this patch.
> > 1. Clear pud/pmd entry.
> > 2. System wide TLB flush <-- TO BE ADDED BY NEW PATCH
> > 3. Free its underlining pmd/pte page.
>
> This still lacks the page-table synchronization and will thus not fix
> the BUG_ON being triggered.
The BUG_ON issue is specific to PAE that it syncs at the pmd level.
x86/64 does not have this issue since it syncs at the pgd or p4d level.
> > We do not need to revert this patch. We can make the above change I
> > mentioned.
>
> Please note that we are not in the merge window anymore and that any fix
> needs to be simple and obviously correct.
Understood. Changing the x86/32 sync point is risky. So, I am going to
revert the free page handling for PAE.
Thanks,
-Toshi
next prev parent reply other threads:[~2018-04-28 20:54 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-14 18:01 [PATCH v2 0/2] fix memory leak / panic in ioremap huge pages Toshi Kani
2018-03-14 18:01 ` Toshi Kani
2018-03-14 18:01 ` [PATCH v2 1/2] mm/vmalloc: Add interfaces to free unmapped page table Toshi Kani
2018-03-14 18:01 ` Toshi Kani
2018-03-14 22:38 ` Andrew Morton
2018-03-14 22:38 ` Andrew Morton
2018-03-15 14:27 ` Kani, Toshi
2018-03-15 14:27 ` Kani, Toshi
2018-03-14 18:01 ` [PATCH v2 2/2] x86/mm: implement free pmd/pte page interfaces Toshi Kani
2018-03-14 18:01 ` Toshi Kani
2018-03-15 7:39 ` Chintan Pandya
2018-03-15 7:39 ` Chintan Pandya
2018-03-15 14:51 ` Kani, Toshi
2018-03-15 14:51 ` Kani, Toshi
2018-04-26 14:19 ` Joerg Roedel
2018-04-26 14:19 ` Joerg Roedel
2018-04-26 16:21 ` Kani, Toshi
2018-04-26 16:21 ` Kani, Toshi
2018-04-26 17:23 ` joro at 8bytes.org
2018-04-26 17:23 ` joro
2018-04-26 17:49 ` Kani, Toshi
2018-04-26 17:49 ` Kani, Toshi
2018-04-26 20:07 ` joro at 8bytes.org
2018-04-26 20:07 ` joro
2018-04-26 22:30 ` Kani, Toshi
2018-04-26 22:30 ` Kani, Toshi
2018-04-27 7:37 ` joro at 8bytes.org
2018-04-27 7:37 ` joro
2018-04-27 11:39 ` Michal Hocko
2018-04-27 11:39 ` Michal Hocko
2018-04-27 11:46 ` joro at 8bytes.org
2018-04-27 11:46 ` joro
2018-04-27 11:52 ` Chintan Pandya
2018-04-27 11:52 ` Chintan Pandya
2018-04-27 12:48 ` joro at 8bytes.org
2018-04-27 12:48 ` joro
2018-04-27 13:42 ` Chintan Pandya
2018-04-27 13:42 ` Chintan Pandya
2018-04-27 14:31 ` Kani, Toshi
2018-04-27 14:31 ` Kani, Toshi
2018-04-28 9:02 ` joro at 8bytes.org
2018-04-28 9:02 ` joro
2018-04-28 20:54 ` Kani, Toshi [this message]
2018-04-28 20:54 ` Kani, Toshi
2018-04-30 7:30 ` Chintan Pandya
2018-04-30 7:30 ` Chintan Pandya
2018-04-30 13:43 ` Kani, Toshi
2018-04-30 13:43 ` Kani, Toshi
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