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Date: Thu, 2 Oct 2008 20:56:04 -0700 From: Andrew Morton <akpm@...ux-foundation.org> To: Nick Piggin <nickpiggin@...oo.com.au> Cc: Mikulas Patocka <mpatocka@...hat.com>, linux-kernel@...r.kernel.org, linux-mm@...r.kernel.org, agk@...hat.com, mbroz@...hat.com, chris@...chsys.com Subject: Re: [PATCH] Memory management livelock On Fri, 3 Oct 2008 13:47:21 +1000 Nick Piggin <nickpiggin@...oo.com.au> wrote: > > I expect there's no solution which avoids blocking the writers at some > > stage. > > See my other email. Something roughly like this would do the trick > (hey, it actually boots and runs and does fix the problem too). It needs exclusion to protect all those temp tags. Is do_fsync()'s i_mutex sufficient? It's qute unobvious (and unmaintainable?) that all the callers of this stuff are running under that lock. > It's ugly because we don't have quite the right radix tree operations > yet (eg. lookup multiple tags, set tag X if tag Y was set, proper range > lookups). But the theory is to up-front tag the pages that we need to > get to disk. Perhaps some callback-calling radix tree walker. > Completely no impact or slowdown to any writers (although it does add > 8 bytes of tags to the radix tree node... but doesn't increase memory > footprint as such due to slab). Can we reduce the amount of copy-n-pasting here? -- 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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