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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2016-03-15 23:40:28 +0300 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2016-03-31 23:33:23 +0300 |
| commit | 5413e24c943da33306047fc091fa34fa4f261b3b (patch) | |
| tree | 01abef5d3bf87b50b20bc581fb89bf955bfeed67 /Documentation/RCU | |
| parent | 6146f8df48cb52c46c256424bd03b567b889b7bb (diff) | |
| download | linux-5413e24c943da33306047fc091fa34fa4f261b3b.tar.xz | |
documentation: Sharpen up the no-readers quick quiz
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'Documentation/RCU')
| -rw-r--r-- | Documentation/RCU/Design/Requirements/Requirements.html | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/Documentation/RCU/Design/Requirements/Requirements.html b/Documentation/RCU/Design/Requirements/Requirements.html index acdad96f78e9..85cf2238fd08 100644 --- a/Documentation/RCU/Design/Requirements/Requirements.html +++ b/Documentation/RCU/Design/Requirements/Requirements.html @@ -1002,18 +1002,21 @@ obligation to wait for these new readers. <tr><th> </th></tr> <tr><th align="left">Quick Quiz:</th></tr> <tr><td> - Suppose that synchronize_rcu() did wait until all readers had completed. - Would the updater be able to rely on this? + Suppose that synchronize_rcu() did wait until <i>all</i> + readers had completed instead of waiting only on + pre-existing readers. + For how long would the updater be able to rely on there + being no readers? </td></tr> <tr><th align="left">Answer:</th></tr> <tr><td bgcolor="#ffffff"><font color="ffffff"> - No. + For no time at all. Even if <tt>synchronize_rcu()</tt> were to wait until all readers had completed, a new reader might start immediately after <tt>synchronize_rcu()</tt> completed. Therefore, the code following - <tt>synchronize_rcu()</tt> cannot rely on there being no readers - in any case. + <tt>synchronize_rcu()</tt> can <i>never</i> rely on there being + no readers. </font></td></tr> <tr><td> </td></tr> </table> |