From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: The long, long life of an inactive_dirty page From: Arjan van de Ven Reply-To: arjanv@redhat.com In-Reply-To: <200405121411.i4CEBt6b011774@newsguy.com> References: <200405121411.i4CEBt6b011774@newsguy.com> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-+eYCnoufQcAqnlSaSSHv" Message-Id: <1084373509.2778.9.camel@laptop.fenrus.com> Mime-Version: 1.0 Date: Wed, 12 May 2004 16:51:50 +0200 Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Crawford Cc: linux-mm@kvack.org List-ID: --=-+eYCnoufQcAqnlSaSSHv Content-Type: text/plain Content-Transfer-Encoding: quoted-printable > It is my understanding that the next thing that should happen is that > page_launder(), which is invoked when memory gets low, should come along = and > get those pages written, and then, on its next pass mark them inactive_cl= ean. >=20 > But in thise case, we have plenty of memory available and absolutely noth= ing > using it. So there's never any memory pressure, page_launder is never cal= led, > and the data is never written to disk. This is arguably a bad thing; an > entirely idle system should not be sitting for hours or days with uncommi= tted > data in RAM for the obvious reason. bdflush and co WILL commit the data to disk after like 30 seconds. They will not move it to inactive_clean; that will happen at the first sight of memory pressure. The code that does that notices that the data isn't dirty and won't do a write-out just a move. > > grep Inact_dirty /proc/meminfo > Inact_dirty: 492240 kB >=20 > [ ~5 minutes later ] >=20 > > grep Inact_dirty /proc/meminfo > Inact_dirty: 463680 kB Inact_dirty isn't guaranteed to be dirty, it's the list of pages that CAN be dirty. > That's 460MB of uncommitted data hanging around on a completely idle mach= ine. >=20 it's not uncommitted, as I said there are other methods that make sure that doesn't happen. --=-+eYCnoufQcAqnlSaSSHv Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) iD8DBQBAojoFxULwo51rQBIRAhClAKCUybZHP7z6XbO7okOP+BaiAloS2gCfQUYb EkH0wIlify3ZwrpkiMQs2Lc= =+Tmw -----END PGP SIGNATURE----- --=-+eYCnoufQcAqnlSaSSHv-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org