Messages in this thread | | | From | "Hillf Danton" <> | Subject | Re: [patch] mm, oom: add comment for why oom_adj exists | Date | Fri, 06 Nov 2015 11:52:01 +0800 |
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> > /proc/pid/oom_adj exists solely to avoid breaking existing userspace > binaries that write to the tunable. > > Add a comment in the only possible location within the kernel tree to > describe the situation and motivation for keeping it around. > > Signed-off-by: David Rientjes <rientjes@google.com> > ---
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
> fs/proc/base.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/fs/proc/base.c b/fs/proc/base.c > --- a/fs/proc/base.c > +++ b/fs/proc/base.c > @@ -1032,6 +1032,16 @@ static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count, > return simple_read_from_buffer(buf, count, ppos, buffer, len); > } > > +/* > + * /proc/pid/oom_adj exists solely for backwards compatibility with previous > + * kernels. The effective policy is defined by oom_score_adj, which has a > + * different scale: oom_adj grew exponentially and oom_score_adj grows linearly. > + * Values written to oom_adj are simply mapped linearly to oom_score_adj. > + * Processes that become oom disabled via oom_adj will still be oom disabled > + * with this implementation. > + * > + * oom_adj cannot be removed since existing userspace binaries use it. > + */ > static ssize_t oom_adj_write(struct file *file, const char __user *buf, > size_t count, loff_t *ppos) > { > --
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