lkml.org 
[lkml]   [2011]   [Jul]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2] staging: zcache: support multiple clients, prep for KVM and RAMster
On Thu, Jun 30, 2011 at 04:28:14PM -0700, Dan Magenheimer wrote:
> Hi Dan --
>
> Thanks for the careful review. You're right... some
> of this was leftover from debugging an off-by-one error,
> though the code as is still works.
>
> OTOH, there's a good chance that much of this sysfs
> code will disappear before zcache would get promoted
> out of staging, since it is to help those experimenting
> with zcache to get more insight into what the underlying
> compression/accept-reject algorithms are doing.
>
> So I hope you (and GregKH) are OK that another version is
> not necessary at this time to fix these.

Off by one errors are kind of insidious. People cut and paste them
and they spread. If someone adds a new list of chunks then there
are now two examples that are correct and two which have an extra
element, so it's 50/50 that he'll copy the right one.

Btw, looking at it again, this seems like maybe a similar issue in
zbud_evict_zbpg():

515 /* now try freeing unbuddied pages, starting with least space avail */
516 for (i = 0; i < MAX_CHUNK; i++) {
517 retry_unbud_list_i:


MAX_CHUNKS is NCHUNKS - 1. Shouldn't that be i < NCHUNKS so that we
reach the last element in the list?

regards,
dan carpenter



\
 
 \ /
  Last update: 2011-07-01 10:41    [W:0.077 / U:0.404 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site