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Date: Mon, 21 Jun 2010 10:56:25 +0200 From: Andi Kleen <andi@...stfloor.org> To: Aleksandr Koltsoff <aleksandr.koltsoff@...s.fi> Cc: linux-kernel@...r.kernel.org Subject: Re: RFC: Exporting NOCMTIME to userspace Aleksandr Koltsoff <aleksandr.koltsoff@...s.fi> writes: > > On the other hand, if someone can suggest a way to avoid timestamp > updates/causing inode writes, I'm all ears and eyes. (using the > block-layer directly or writing a custom fs is not really an elegant > solution, IMO). I recently looked at this for some other reason. One of the reasons c/m time became a problem recently are sub second time stamps in newer file systems, which can be a performance problem on some extreme loads (updating the time stamp requires taking locks and takes CPU time) I think what would be better would be to have flush intervals that specify that m/c time are only flushed with longer intervals (similar to the deferred atime that's now in there) This would still cause the inode to be written if it gets flushed from memory on low memory and occasionally depending on the interval, but most of the writes would be gone. All still with the same semantics. I think doing it this way would be preferable over just disabling it. -Andi -- ak@...ux.intel.com -- Speaking for myself only. -- 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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