From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Tue, 29 Jun 1999 22:08:52 +0200 (CEST)
From: Andrea Arcangeli <andrea@suse.de>
Subject: Re: filecache/swapcache questions [RFC] [RFT] [PATCH] kanoj-mm12-2.3.8
 Fix swapoff races
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To: Chuck Lever <cel@monkey.org>
Cc: "Stephen C. Tweedie" <sct@redhat.com>, Kanoj Sarcar <kanoj@google.engr.sgi.com>, torvalds@transmeta.com, linux-mm@kvack.org
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On Tue, 29 Jun 1999, Andrea Arcangeli wrote:

For the record: the snapshot wasn't SMP safe.

> 	/*
>+	 * We can release the big kernel lock here since
>+	 * kswapd will see the page locked. -Andrea
>+	 */
>+	unlock_kernel();

This was a bit too early (pefectly ok for kswapd but not ok for the swap
cache SMP safety). We must first take over the swap cache and run
swap_count before be allowed to release the big kernel lock. So this
should be moved a bit lower...

Andrea

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