From: kanoj@google.engr.sgi.com (Kanoj Sarcar)
To: Kanoj Sarcar <kanoj@google.engr.sgi.com>
Cc: Andrea Arcangeli <andrea@suse.de>, Ben LaHaise <bcrl@redhat.com>,
riel@nl.linux.org, Linus Torvalds <torvalds@transmeta.com>,
linux-mm@kvack.org
Subject: Re: [patch] take 2 Re: PG_swap_entry bug in recent kernels
Date: Fri, 7 Apr 2000 17:37:30 -0700 (PDT) [thread overview]
Message-ID: <200004080037.RAA32924@google.engr.sgi.com> (raw)
In-Reply-To: <200004080011.RAA21305@google.engr.sgi.com> from "Kanoj Sarcar" at Apr 07, 2000 05:11:15 PM
> >
> > >Also, did you have a good reason to want to make lookup_swap_cache()
> > >invoke find_get_page(), and not find_lock_page()? I coded some of the
> >
> > Using find_lock_page and then unlocking the page is meaningless. If you
> > are going to unconditionally unlock the page then you shouldn't lock it in
> > first place.
>
> I will have to think a little bit about why the code does what it does
> currently. I will let you know ...
>
Okay, I think I found at least one reason why the lockpage was being done
in lookup_swap_cache(). It was effectively to check the PageSwapCache bit,
since shrink_mmap:__delete_from_swap_cache could race with a
lookup_swap_cache.
Yes, I did notice the recent shrink_mmap SMP race fixes that you posted,
now it _*might*_ be unneccesary to do a find_lock_page() in
lookup_swap_cache() (just for this race). I will have to look at the
latest prepatch to confirm that. In any case, there are still races with
swapspace deletion and swapcache lookup, so unless you had a good reason
to want to replace the find_lock_page with lookup_swap_cache, I would much
rather see it the way it is currently ...
Kanoj
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next prev parent reply other threads:[~2000-04-08 0:37 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-04-03 22:22 PG_swap_entry bug in recent kernels Ben LaHaise
2000-04-04 15:06 ` Andrea Arcangeli
2000-04-04 15:46 ` Rik van Riel
2000-04-04 16:50 ` Andrea Arcangeli
2000-04-04 17:06 ` Ben LaHaise
2000-04-04 18:03 ` Andrea Arcangeli
2000-04-06 22:11 ` [patch] take 2 " Ben LaHaise
2000-04-07 10:45 ` Andrea Arcangeli
2000-04-07 11:29 ` Rik van Riel
2000-04-07 12:00 ` Andrea Arcangeli
2000-04-07 12:54 ` Rik van Riel
2000-04-07 13:14 ` Andrea Arcangeli
2000-04-07 20:12 ` Kanoj Sarcar
2000-04-07 23:26 ` Andrea Arcangeli
2000-04-08 0:11 ` Kanoj Sarcar
2000-04-08 0:37 ` Kanoj Sarcar [this message]
2000-04-08 13:20 ` Andrea Arcangeli
2000-04-08 21:39 ` Kanoj Sarcar
2000-04-08 23:02 ` Andrea Arcangeli
2000-04-08 23:18 ` Kanoj Sarcar
2000-04-08 23:58 ` Andrea Arcangeli
2000-04-08 13:30 ` Andrea Arcangeli
2000-04-08 17:39 ` Andrea Arcangeli
2000-04-07 23:54 ` Andrea Arcangeli
2000-04-08 0:15 ` Kanoj Sarcar
2000-04-08 13:14 ` Andrea Arcangeli
2000-04-08 21:47 ` Kanoj Sarcar
2000-04-08 23:10 ` Andrea Arcangeli
2000-04-08 23:21 ` Kanoj Sarcar
2000-04-08 23:39 ` Andrea Arcangeli
2000-04-09 0:40 ` Kanoj Sarcar
2000-04-10 8:55 ` andrea
2000-04-11 2:45 ` Kanoj Sarcar
2000-04-11 16:22 ` Andrea Arcangeli
2000-04-11 17:40 ` Rik van Riel
2000-04-11 18:20 ` Kanoj Sarcar
2000-04-21 18:23 ` Andrea Arcangeli
2000-04-21 21:00 ` Rik van Riel
2000-04-22 1:12 ` Andrea Arcangeli
2000-04-22 1:51 ` Linus Torvalds
2000-04-22 18:29 ` Rik van Riel
2000-04-22 19:58 ` Linus Torvalds
2000-04-11 18:26 ` Kanoj Sarcar
2000-04-10 19:10 ` Stephen C. Tweedie
2000-04-08 0:04 ` Andrea Arcangeli
[not found] <yttem7xstk2.fsf@vexeta.dc.fi.udc.es>
2000-04-23 0:52 ` Andrea Arcangeli
[not found] <yttk8ho26s8.fsf@vexeta.dc.fi.udc.es>
2000-04-23 16:07 ` Andrea Arcangeli
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