From: Zlatko Calusic <Zlatko.Calusic@CARNet.hr>
To: "Eric W. Biederman" <ebiederm+eric@ccr.net>
Cc: Linux-MM List <linux-mm@kvack.org>,
Linux Kernel List <linux-kernel@vger.rutgers.edu>
Subject: Re: Removing swap lockmap...
Date: 19 Jan 1999 02:37:49 +0100 [thread overview]
Message-ID: <871zksqbyq.fsf@atlas.CARNet.hr> (raw)
In-Reply-To: ebiederm+eric@ccr.net's message of "18 Jan 1999 18:34:50 -0600"
ebiederm+eric@ccr.net (Eric W. Biederman) writes:
> >>>>> "ZC" == Zlatko Calusic <Zlatko.Calusic@CARNet.hr> writes:
>
>
> ZC> I removed swap lockmap all together and, to my surprise, I can't
> ZC> produce any ill behaviour on my system, not even under very heavy
> ZC> swapping (in low memory condition).
>
> ZC> I remember there were some issues when swap lockmap was removed in
> ZC> 2.1.89, so it was reintroduced later (processes were dying randomly).
>
>
> ZC> Question is, why is everything running so smoothly now, even without
> ZC> swap lockmap?
>
> For this patch to be safe we need to
> A) Fix sysv shm to use the swap cache.
Yes, this case probably doesn't get enough testing with my current
setup, so it is quite hard (for me) to prove removing lockmap is
no-no. Problem is that I don't understand shm swapping very well, it
is piggybacked on "regular" MM as a special case, and I didn't had
time to go through it, yet.
> B) garantee that shrink_mmap is the only place that
> removes a page from the swap cache, and that it never removes
> a page while I/O is in progress, (as Stephen said).
>
> This means a lot of the current cases like delete_from_swap_cache,
> and free_page_and_swap_cache need to be removed.
Yes, I believe you on this one.
>
> And we need to be very carefull when we break down the swap cache,
> and make it an unshared page.
>
> The change to normally remove pages with shrink_mmap is what makes it
> mostly safe now.
>
> For 2.3 it should go. For 2.2 it should stay.
>
I'll still be testing it, nevertheless. Maybe after some time I get in
some trouble, and then at least I'll know what to do. :-)
Regards,
--
Zlatko
--
This is a majordomo managed list. To unsubscribe, send a message with
the body 'unsubscribe linux-mm me@address' to: majordomo@kvack.org
next prev parent reply other threads:[~1999-01-19 1:38 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-01-18 15:12 Removing swap lockmap Zlatko Calusic
1999-01-18 20:26 ` Andrea Arcangeli
1999-01-18 22:24 ` BUG: deadlock in swap lockmap handling Alan Cox
1999-01-18 21:46 ` Removing swap lockmap Stephen C. Tweedie
1999-01-19 1:33 ` Zlatko Calusic
1999-01-19 0:34 ` Eric W. Biederman
1999-01-19 1:37 ` Zlatko Calusic [this message]
1999-01-19 18:15 ` Andrea Arcangeli
1999-01-20 17:09 ` Stephen C. Tweedie
1999-01-20 18:14 ` Zlatko Calusic
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=871zksqbyq.fsf@atlas.CARNet.hr \
--to=zlatko.calusic@carnet.hr \
--cc=ebiederm+eric@ccr.net \
--cc=linux-kernel@vger.rutgers.edu \
--cc=linux-mm@kvack.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.