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Open Source and information security mailing list archives
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Date: Wed, 25 Oct 2006 11:10:22 +0200 From: Pavel Machek <pavel@....cz> To: Nigel Cunningham <ncunningham@...uxmail.org> Cc: "Rafael J. Wysocki" <rjw@...k.pl>, Andrew Morton <akpm@...l.org>, LKML <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] Use extents for recording what swap is allocated. Hi! > > > > And now, can you do same computation assuming the swap allocator goes > > > > completely crazy, and free space is in 1-page chunks? > > > > > > The worst case is 3 * sizeof(unsigned long) * > > > number_of_swap_extents_allocated bytes. > > > > Okay, so if we got 4GB of swap space, thats 1MB swap pages, worst case > > is you have one extent per page, on x86-64 that's 24MB. +kmalloc > > overhead, I assume? > > Sounds right. Ok, 24-50MB per 4GB of swap space is not _that_ bad... > > And you do linear walks over those extents, leading to O(n^2) > > algorithm, no? That has bitten us before... > > We start from where we last added an extent on the chain by default. ...but linear search through 24MB _is_ going to hurt. > You're not going to respond to the other bit of my reply? I was > beginning to think you were being more reasonable this time. Oh well. Rafael likes your code, and that's a big plus, but do you have to insult me?! Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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