Re: [patch] reiserfs support for laptop_mode

[Nikita Danilov <Nikita@Namesys.COM>]

Micha Feigin writes:
 > I've been using this since 2.4.22 and since laptop_mode is in the
 > kernel since 2.4.23-pre<something> and I haven't seen that anyone else
 > has implemented this so I decided to post it on the list in case anyone
 > is interested.
 > It a patch to modify the journal flush time of reiserfs to support
 > laptop_mode (same functionality as ext3 has already).
 > The times are taken from bdflush.

Support for reiserfs laptop mode is in 2.6 now. It is done by adding new
mount option "commit=N" that sets commit interval in seconds.

It doesn't look right to just plainly set reiserfs commit interval to be
the same as the ext3 commit interval.

 > 
 > --- kernel-source-2.4.25-pre6/fs/reiserfs/journal.c	2003-08-25 14:44:43.000000000 +0300
 > +++ kernel-source-2.4.25-pre6.new/fs/reiserfs/journal.c	2003-10-20 03:35:58.000000000 +0200
 > @@ -58,6 +58,7 @@
 >  #include <linux/stat.h>
 >  #include <linux/string.h>
 >  #include <linux/smp_lock.h>
 > +#include <linux/fs.h>
 >  
 >  /* the number of mounted filesystems.  This is used to decide when to
 >  ** start and kill the commit thread
 > @@ -2659,8 +2660,12 @@
 >    /* starting with oldest, loop until we get to the start */
 >    i = (SB_JOURNAL_LIST_INDEX(p_s_sb) + 1) % JOURNAL_LIST_COUNT ;
 >    while(i != start) {
 > -    if (SB_JOURNAL_LIST(p_s_sb)[i].j_len > 0 && ((now - SB_JOURNAL_LIST(p_s_sb)[i].j_timestamp) > SB_JOURNAL_MAX_COMMIT_AGE(p_s_sb) ||
 > -       immediate)) {
 > +    /* get_buffer_age() / HZ is used since the time returned by
 > +     * get_buffer_age is in sec * HZ and the journal time is taken in seconds.
 > +     */
 > +    if (SB_JOURNAL_LIST(p_s_sb)[i].j_len > 0 &&
 > +	((now - SB_JOURNAL_LIST(p_s_sb)[i].j_timestamp) > get_buffer_age() / HZ
 > +	 || immediate)) {

Nikita.