Date: Tue, 16 Oct 2007 19:42:34 +1000 From: Peter Jeremy <peterjeremy@optushome.com.au> To: William LeFebvre <bill@lefebvre.org> Cc: freebsd-stable@freebsd.org Subject: Re: Question about 'top' values on memory usage, now threads Message-ID: <20071016094234.GM1184@turion.vk2pj.dyndns.org> In-Reply-To: <471398BB.30405@lefebvre.org> References: <008801c80e66$7be49490$0c00a8c0@Artem> <471367F2.7050303@lefebvre.org> <037501c80f3d$69120730$0c00a8c0@Artem> <471398BB.30405@lefebvre.org>
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--Km1U/tdNT/EmXiR1 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2007-Oct-15 12:43:39 -0400, William LeFebvre <bill@lefebvre.org> wrote: >Whether there is actual swapping going on or not, processes will still nee= d=20 >swap space. There needs to be a backing store for every page that's in=20 >physical memory. This isn't true for FreeBSD. You can even totally disable paging/swapping with the config option "NO_SWAPPING" if you want. FreeBSD allocates swap space on an "as needed" basis, rather than pre-allocating swap. The advantage is that a process can request virtually unlimited amounts of memory via sbrk(2), mmap(2) or malloc(3). The downside is that a process may be killed without notice when it writes to some previously allocated but unused part of its address space. See the archives for the full bikeshed. --=20 Peter Jeremy --Km1U/tdNT/EmXiR1 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (FreeBSD) iD8DBQFHFIeK/opHv/APuIcRAoE2AKCoLsAOgaudTZDIVIgl9L9NNpMx6QCdHf1+ ygC73MLtgKilxCdi2Z2+57c= =eHd/ -----END PGP SIGNATURE----- --Km1U/tdNT/EmXiR1--
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