On Wed, Mar 08, 2023 at 11:23:45AM +0100, Vlastimil Babka wrote: > > > On 3/6/23 07:05, ye.xingchen@xxxxxxxxxx wrote: > > From: Minghao Chi <chi.minghao@xxxxxxxxxx> > > > > Available only when CONFIG_COMPACTION is set. When 1 is written to > > the file, all zones are compacted such that free memory is available > > in contiguous blocks where possible. > > But echo others-parameter > compact_memory, this function will be > > triggered by writing parameters to the interface. > > > > Applied this patch, > > sh/$ echo 1.1 > /proc/sys/vm/compact_memory > > sh/$ sh: write error: Invalid argument > > The start and end time of printing triggering compact_memory. > > > > Link: https://lore.kernel.org/all/ZAJwoXJCzfk1WIBx@xxxxxxxxxxxxxxxxxxxxxx/ > > Signed-off-by: Minghao Chi <chi.minghao@xxxxxxxxxx> > > Signed-off-by: Ye Xingchen <ye.xingchen@xxxxxxxxxx> > > --- > > mm/compaction.c | 12 +++++++++++- > > 1 file changed, 11 insertions(+), 1 deletion(-) > > > > diff --git a/mm/compaction.c b/mm/compaction.c > > index 5a9501e0ae01..2c9ecc4b9d23 100644 > > --- a/mm/compaction.c > > +++ b/mm/compaction.c > > @@ -2763,6 +2763,8 @@ int compaction_proactiveness_sysctl_handler(struct ctl_table *table, int write, > > return 0; > > } > > > > +/* The written value is actually unused, all memory is compacted */ > > +int sysctl_compact_memory; > > /* > > * This is the entry point for compacting all nodes via > > * /proc/sys/vm/compact_memory > > @@ -2770,8 +2772,16 @@ int compaction_proactiveness_sysctl_handler(struct ctl_table *table, int write, > > int sysctl_compaction_handler(struct ctl_table *table, int write, > > void *buffer, size_t *length, loff_t *ppos) > > { > > - if (write) > > + int ret; > > + > > + ret = proc_dointvec_minmax(table, write, buffer, length, ppos); > > + if (ret) > > + return ret; > > + if (write) { > > + pr_info("compact_nodes start\n"); > > compact_nodes(); > > + pr_info("compact_nodes end\n"); > > I'm not sure we want to start spamming the dmesg. This would make sense > if we wanted to deprecate the sysctl and start hunting for remaining > callers to be fixed. Otherwise ftrace can be used to capture e.g. the time. Without that print, I don't think a custom proc handler is needed too, right? So what would simplify the code. Luis
