Date: Fri, 23 Mar 2007 00:55:05 +0100 From: "Michael Schuh" <michael.schuh@gmail.com> To: "Chuck Swiger" <cswiger@mac.com> Cc: FreeBSD Stable <freebsd-stable@freebsd.org> Subject: Re: another error with md malloc based fs Message-ID: <1dbad3150703221655w62284ed7o8a5c7440aca45891@mail.gmail.com> In-Reply-To: <9363AFA5-0DEF-428A-A6D4-E04A4A414F0B@mac.com> References: <1dbad3150703221504u71e3db44sbefeed758ed253db@mail.gmail.com> <20070322230314.257D445047@ptavv.es.net> <1dbad3150703221617g488c3e96t20e552fc41c265a5@mail.gmail.com> <9363AFA5-0DEF-428A-A6D4-E04A4A414F0B@mac.com>
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Hi Chuck, 2007/3/23, Chuck Swiger <cswiger@mac.com>: > > On Mar 22, 2007, at 4:17 PM, Michael Schuh wrote: > > i can't understand how malloc can eat all available > > memory, i have 2Gigs of it ;-) > > so it seems to me i know what i doing, if > > i have 1,6 Gigs free Memory, and i say ok get me 750Megs from > > my 1,6 Gigs of free Memory, what was faulty on that???? > > The two choices involve a swap-based RAMdisk, which can use all of > the available physical RAM it needs to, since this memory is > swappable, or a kernel-memory-based RAMdisk, which uses wired-down > memory from within the kernel. Ok, so that is it harder to understand for me in the first time, if i understand it now right the swap or file based memory backend is also in the ram, but it get another way managed from kernels vm. the malloc based ramdisk get's not reallly managed by the kvm, but it underlays under the paging and swapping, and also ba the "thread-killer" there shot's thread down it it get's to much work for the system.... i hope i understand this right, it is important for me... You shouldn't or can't create huge kernel-based RAMdisks without > expanding the amount of KVM available to the kernel...it's not > reasonable to wire down hundreds of MB or RAM in almost all situations. > > > i hope it gave another way to use such ram-disk without using > > swap or other harddisk based backend....otoh my ram is not fully > > useful > > for me and i must, after twelve years of using freebsd, looking > > back to > > linux, and that i never would, only for using ramdisks.... > > If you wanted to create a 10MB RAMdisk, using kernel-based memory > would be fine. > > For things which are much larger than that, the kernel's global VM > management is using techniques like page-fault frequency heuristics > and will do a better job of keeping active stuff cached in RAM > (regardless of whether the stuff is part of a running process or part > of your RAMdisk filesystem), if you let the kernel manage the > situation than if you try to configure hundreds of MB which can only > be used for a RAMdisk. > > Anyway, if you want to use Linux instead, nobody here is going to try > to persuade you to do otherwise. Have fun, nop, i don't runaway, i don't disappear to run over to "dead rats" :-D i will stick to FreeBSD, than i believe it gave no better OS for me :-D i have many fun with my "lovely" BSD..... at this time it gave only one situation in that i use linux and i hope this changes i the near future (VMWare....:-( ) thanks for helping to see things a little bit more clear.... regards michael > -- > -Chuck > > --=20 =3D=3D=3D michael-schuh.net =3D=3D=3D Michael Schuh Preu=DFenstr. 13 66111 Saarbr=FCcken phone: 0681/8319664 mobil: 0177/9738644 @: michael.schuh@gmail.com =3D=3D=3D Ust-ID: DE251072318 =3D=3D=3D
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