On Wed, 20 Oct 2021 07:21:21 +0000 SeongJae Park <sj@xxxxxxxxxx> wrote: > On Wed, 20 Oct 2021 09:42:33 +0800 Xin Hao <xhao@xxxxxxxxxxxxxxxxx> wrote: > > > When the ctx->adaptive_targets list is empty, > > I did some test on monitor_on interface like this. > > > > # echo > /sys/kernel/debug/damon/target_ids > > Thanks for the change, but you missed writing 'on' to 'monitor_on' in the above > example. > > > > > Though the ctx->adaptive_targets list is empty, but the > > kthread_run still be called, and the kdamond.x thread still > > be created, this is meaningless. > > > > So there adds a judgment in 'dbgfs_monitor_on_write', > > if the ctx->adaptive_targets list is empty, return -EINVAL. > > > > Signed-off-by: Xin Hao <xhao@xxxxxxxxxxxxxxxxx> > > Other parts looks good to me. However, seems this commit conflicts with a > patch[1] which already merged in -mm tree. Could you please rebase this on it? > FYI, all DAMON patches that merged in -mm tree are also applied on DAMON > development tree. So, you could get the patch applied tree by: > > $ git remote add sj git://git.kernel.org/pub/scm/linux/kernel/git/sj/linux.git > $ git fetch sj > $ git checkout 0fa378d04b12 > > [1] https://lore.kernel.org/linux-mm/20211014073014.35754-1-sj@xxxxxxxxxx/ > > > Thanks, > SJ > > > --- > > include/linux/damon.h | 1 + > > mm/damon/core.c | 5 +++++ > > mm/damon/dbgfs.c | 13 ++++++++++--- > > 3 files changed, 16 insertions(+), 3 deletions(-) > > > > diff --git a/include/linux/damon.h b/include/linux/damon.h > > index 715dadd21f7c..4fce5f1f6dad 100644 > > --- a/include/linux/damon.h > > +++ b/include/linux/damon.h > > @@ -316,6 +316,7 @@ void damon_destroy_scheme(struct damos *s); > > > > struct damon_target *damon_new_target(unsigned long id); > > void damon_add_target(struct damon_ctx *ctx, struct damon_target *t); > > +bool damon_targets_empty(struct damon_ctx *ctx); > > void damon_free_target(struct damon_target *t); > > void damon_destroy_target(struct damon_target *t); > > unsigned int damon_nr_regions(struct damon_target *t); > > diff --git a/mm/damon/core.c b/mm/damon/core.c > > index 2f6785737902..c3a1374dbe0b 100644 > > --- a/mm/damon/core.c > > +++ b/mm/damon/core.c > > @@ -156,6 +156,11 @@ void damon_add_target(struct damon_ctx *ctx, struct damon_target *t) > > list_add_tail(&t->list, &ctx->adaptive_targets); > > } > > > > +bool damon_targets_empty(struct damon_ctx *ctx) > > +{ > > + return list_empty(&ctx->adaptive_targets); > > +} > > + > > static void damon_del_target(struct damon_target *t) > > { > > list_del(&t->list); > > diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c > > index 38188347d8ab..9dee29f7d103 100644 > > --- a/mm/damon/dbgfs.c > > +++ b/mm/damon/dbgfs.c > > @@ -865,12 +865,19 @@ static ssize_t dbgfs_monitor_on_write(struct file *file, > > return -EINVAL; > > } > > > > - if (!strncmp(kbuf, "on", count)) > > + if (!strncmp(kbuf, "on", count)) { > > + int i; > > + > > + for (i = 0; i < dbgfs_nr_ctxs; i++) { > > + if (damon_targets_empty(dbgfs_ctxs[i])) > > + return -EINVAL; Oops, I forgot that you should 'kfree(kbuf)' before returning here. Please do that. Thanks, SJ > > + } > > err = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs); > > - else if (!strncmp(kbuf, "off", count)) > > + } else if (!strncmp(kbuf, "off", count)) { > > err = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs); > > - else > > + } else { > > err = -EINVAL; > > + } > > > > if (err) > > ret = err; > > -- > > 2.31.0 > >
