From: "Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com>
To: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Shakeel Butt <shakeelb@google.com>,
Minchan Kim <minchan@kernel.org>,
"Mike Galbraith" <efault@gmx.de>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
NitinGupta <ngupta@vflare.org>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
"tiantao (H)" <tiantao6@hisilicon.com>
Subject: RE: [PATCH] zsmalloc: do not use bit_spin_lock
Date: Tue, 22 Dec 2020 02:10:42 +0000 [thread overview]
Message-ID: <08cbef1e43634c4099709be8e99e5d27@hisilicon.com> (raw)
In-Reply-To: CAM4kBBK=5eBdCjWc5VJXcdr=Z4PV1=ZQ2n8fZmJ6ahJbpUyv2A@mail.gmail.com
> -----Original Message-----
> From: Song Bao Hua (Barry Song)
> Sent: Tuesday, December 22, 2020 3:03 PM
> To: 'Vitaly Wool' <vitaly.wool@konsulko.com>
> Cc: Shakeel Butt <shakeelb@google.com>; Minchan Kim <minchan@kernel.org>; Mike
> Galbraith <efault@gmx.de>; LKML <linux-kernel@vger.kernel.org>; linux-mm
> <linux-mm@kvack.org>; Sebastian Andrzej Siewior <bigeasy@linutronix.de>;
> NitinGupta <ngupta@vflare.org>; Sergey Senozhatsky
> <sergey.senozhatsky.work@gmail.com>; Andrew Morton
> <akpm@linux-foundation.org>; tiantao (H) <tiantao6@hisilicon.com>
> Subject: RE: [PATCH] zsmalloc: do not use bit_spin_lock
>
>
> > I'm still not convinced. Will kmap what, src? At this point src might become
> just a bogus pointer.
>
> As long as the memory is still there, we can kmap it by its page struct. But
> if
> it is not there anymore, we have no way.
>
> > Why couldn't the object have been moved somewhere else (due to the compaction
> mechanism for instance)
> > at the time DMA kicks in?
>
> So zs_map_object() will guarantee the src won't be moved by holding those
> preemption-disabled lock?
> If so, it seems we have to drop the MOVABLE gfp in zswap for zsmalloc case?
>
Or we can do get_page() to avoid the movement of the page.
> >
> > >
> > > ~Vitaly
> >
>
> Thanks
> Barry
next prev parent reply other threads:[~2020-12-22 2:11 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-19 10:04 [patch] zswap: fix zswap_frontswap_load() vs zsmalloc::map/unmap() might_sleep() splat Mike Galbraith
2020-12-19 10:04 ` Mike Galbraith
2020-12-19 10:12 ` Mike Galbraith
2020-12-19 10:12 ` Mike Galbraith
2020-12-19 10:20 ` Vitaly Wool
2020-12-19 10:20 ` Vitaly Wool
2020-12-19 10:27 ` Mike Galbraith
2020-12-19 10:27 ` Mike Galbraith
2020-12-19 10:46 ` Vitaly Wool
2020-12-19 10:46 ` Vitaly Wool
2020-12-19 10:59 ` Mike Galbraith
2020-12-19 10:59 ` Mike Galbraith
2020-12-19 11:03 ` Mike Galbraith
2020-12-19 11:03 ` Mike Galbraith
2020-12-20 0:22 ` [PATCH] zsmalloc: do not use bit_spin_lock Vitaly Wool
2020-12-20 1:18 ` Matthew Wilcox
2020-12-20 7:21 ` Vitaly Wool
2020-12-20 7:21 ` Vitaly Wool
2021-01-14 16:17 ` Sebastian Andrzej Siewior
2020-12-20 1:23 ` Mike Galbraith
2020-12-20 1:23 ` Mike Galbraith
2020-12-20 4:11 ` Mike Galbraith
2020-12-20 4:11 ` Mike Galbraith
2020-12-20 7:47 ` Mike Galbraith
2020-12-20 7:47 ` Mike Galbraith
2020-12-20 21:20 ` Song Bao Hua (Barry Song)
2020-12-20 22:10 ` Mike Galbraith
2020-12-20 1:56 ` Mike Galbraith
2020-12-20 1:56 ` Mike Galbraith
2020-12-21 17:24 ` Minchan Kim
2020-12-21 19:20 ` Vitaly Wool
2020-12-21 19:20 ` Vitaly Wool
2020-12-21 19:50 ` Shakeel Butt
2020-12-21 19:50 ` Shakeel Butt
2020-12-21 20:05 ` Song Bao Hua (Barry Song)
2020-12-21 21:02 ` Shakeel Butt
2020-12-21 21:02 ` Shakeel Butt
2020-12-21 21:25 ` Song Bao Hua (Barry Song)
2020-12-21 22:11 ` Vitaly Wool
2020-12-21 22:11 ` Vitaly Wool
2020-12-21 22:42 ` Song Bao Hua (Barry Song)
2020-12-21 23:35 ` Song Bao Hua (Barry Song)
2020-12-22 0:59 ` Vitaly Wool
2020-12-22 0:59 ` Vitaly Wool
2020-12-22 1:10 ` Song Bao Hua (Barry Song)
2020-12-22 1:42 ` Song Bao Hua (Barry Song)
2020-12-22 1:57 ` Vitaly Wool
2020-12-22 2:07 ` Song Bao Hua (Barry Song)
2020-12-22 2:10 ` Song Bao Hua (Barry Song) [this message]
2020-12-22 9:44 ` Vitaly Wool
2020-12-22 9:44 ` Vitaly Wool
2020-12-22 21:06 ` Song Bao Hua (Barry Song)
2020-12-23 0:11 ` Vitaly Wool
2020-12-23 0:11 ` Vitaly Wool
2020-12-23 12:44 ` tiantao (H)
2020-12-23 18:25 ` Vitaly Wool
2020-12-23 18:25 ` Vitaly Wool
2021-01-14 16:18 ` Sebastian Andrzej Siewior
2021-01-14 16:29 ` Vitaly Wool
2021-01-14 16:29 ` Vitaly Wool
2021-01-14 16:56 ` Sebastian Andrzej Siewior
2021-01-14 17:15 ` Vitaly Wool
2021-01-14 17:15 ` Vitaly Wool
2021-01-14 17:18 ` Sebastian Andrzej Siewior
2020-12-21 22:46 ` Shakeel Butt
2020-12-21 22:46 ` Shakeel Butt
2020-12-21 23:02 ` Song Bao Hua (Barry Song)
2020-12-22 9:20 ` David Laight
2020-12-22 9:32 ` Vitaly Wool
2020-12-21 20:22 ` Minchan Kim
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