On Fri, Apr 8, 2022 at 6:43 AM Dan Schatzberg schatzberg.dan@gmail.com wrote:
On Fri, Apr 08, 2022 at 04:57:40AM +0000, Yosry Ahmed wrote:
+static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf,
size_t nbytes, loff_t off)+{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));unsigned int nr_retries = MAX_RECLAIM_RETRIES;unsigned long nr_to_reclaim, nr_reclaimed = 0;int err;buf = strstrip(buf);err = page_counter_memparse(buf, "", &nr_to_reclaim);Is there a reason not to support "max"? Empty string seems odd to me here.
We can certainly support "max" to reclaim as much as we can with MAX_RECLAIM_RETRIES, if there are no objections from the maintainers.
if (err)return err;while (nr_reclaimed < nr_to_reclaim) {unsigned long reclaimed;if (signal_pending(current))break;I think this should be `return -EINTR;`
Yes this makes more sense. I think this was modeled after the if block in memory_high_write(), but maybe it makes sense there to just report success as the new high limit was set anyway. Will change it in the next version.
reclaimed = try_to_free_mem_cgroup_pages(memcg,nr_to_reclaim - nr_reclaimed,GFP_KERNEL, true);if (!reclaimed && !nr_retries--)break;Here you can just `return -EAGAIN;`
Will do.
nr_reclaimed += reclaimed;}return nr_reclaimed < nr_to_reclaim ? -EAGAIN : nbytes;Then this can just be `return nbytes;`
Will do.
I'm very much in favor of this new interface. Thanks for working on it!
Thanks so much for reviewing it!