Date: Sun, 03 Feb 2013 12:10:54 +0200 From: Andriy Gapon <avg@FreeBSD.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: freebsd-arch@FreeBSD.org Subject: Re: axe vm.max_wired Message-ID: <510E37AE.8060206@FreeBSD.org> In-Reply-To: <20130202162509.GZ2522@kib.kiev.ua> References: <CAF6rxgmDW21aPJ5Mp6Tbk1z02ivw4UPhSaNEX%2BWiu7O0v13skA@mail.gmail.com> <20120517055425.GA802@infradead.org> <4FC762DD.90101@FreeBSD.org> <4FC81D9C.2080801@FreeBSD.org> <4FC8E29F.2010806@shatow.net> <4FC95A10.7000806@freebsd.org> <4FC9F94B.8060708@FreeBSD.org> <51098977.4000603@FreeBSD.org> <20130131091853.GI2522@kib.kiev.ua> <510B7B92.4030804@FreeBSD.org> <20130202162509.GZ2522@kib.kiev.ua>
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on 02/02/2013 18:25 Konstantin Belousov said the following: > On Fri, Feb 01, 2013 at 10:23:46AM +0200, Andriy Gapon wrote: >> So, I still think that vm.max_wired as it is used now is too arbitrary and too >> indiscriminate to be useful. > It is sized well to the default size of the buffer map, which takes 10% > of the physical RAM of the machine. Since buffers wiring the pages, be > it VMIO or malloc buffer, this leaves 20% for other things, like mbufs, > page tables and user wires. That's the attitude that I don't agree with. "We leave 20% for user wirings, that should be enough for everyone." If it's not enough then you must tune. I rather prefer an approach where we say this is the least amount of memory that should stay unwired. The rest is up to a user. >> There are other tools to limit page wiring by userland e.g. memlocked limit. > The memlock limit is per-process. It is completely useless as the safety > measure. There is also a limit on number of processes, etc. >> But, as I've said in the original email, I can agree with vm.max_wired >> usefulness if it is set to something more reasonable by default. >> IMO, it should not be a fixed percentage of available memory, it should be >> derived from other VM thresholds related to paging. > > Might be. Please provide a suggestion or better, a change. On my to do list. -- Andriy Gapon
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