Messages in this thread | | | Subject | Re: [PATCH 3/5] pagemap: Make pagemap_read enforce reading in multiples of 8 | From | Matt Mackall <> | Date | Thu, 05 Jun 2008 11:09:35 -0500 |
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On Thu, 2008-06-05 at 12:05 -0400, Thomas Tuttle wrote: > On Thu, Jun 5, 2008 at 12:03 PM, Matt Mackall <mpm@selenic.com> wrote: > > > > On Thu, 2008-06-05 at 11:06 -0400, Thomas Tuttle wrote: > >> Since kpagecount and kpageflags require reads in multiples of 8, and > >> it simplifies add_to_pagemap significantly, I added the same > >> requirement to /proc/pid/pagemap. > > > > I'm generally fine with this. Another approach that's perhaps more > > friendly is when someone tries to do a 24-byte read, do a 16-byte read, > > leaving the file pointer aligned. Not sure if that's completely kosher > > though. > > This doesn't require that they read exactly 8 bytes, just that they > read some multiple of 8 bytes. (They can read 8, 16, 24, etc..., just > not something like 12.)
Yes, I got that, I'm just mathematically impaired this morning. Read that as "when someone tries to do a *20* byte read, do a 16-byte read.." In other words, round down to the nearest multiple of 8.
-- Mathematics is the supreme nostalgia of our time.
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