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Date: Sun, 14 Dec 2014 22:38:45 -0800 From: "Darrick J. Wong" <darrick.wong@...cle.com> To: "Theodore Ts'o" <tytso@....edu> Cc: linux-ext4@...r.kernel.org Subject: Re: [PATCH 13/47] libext2fs: add a way to check the theoretical maximum extent tree depth On Sun, Dec 14, 2014 at 10:48:22PM -0500, Theodore Ts'o wrote: > On Sat, Dec 13, 2014 at 07:11:11PM -0800, Darrick J. Wong wrote: > > > But if you look at the above code, there is nothing which is inode or > > > handle specific. The value is only dependent on fs->blocksize. But > > > to calculate this value the function calls ul_log2 three times, which > > > is implemented using a looping construct. So we will be recalculating > > > what is effectively a constant value every single inode in an ext4 > > > file system, which seems very unfortunate. > > > > How about I save the last fs->blocksize and the last result, and return the > > cached last result if fs->blocksize == lastblocksize? > > That sounds like a plan. BTW, it looks like I had accidentally > included this in the next branch, but adding a cache won't disturb the > API, so that's fine. Ok, I'll send the patch that adds the cache. --D > > - Ted > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@...r.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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