Messages in this thread | | | From | Albert Vaca Cintora <> | Date | Thu, 25 Apr 2019 23:39:58 +0200 | Subject | Re: [PATCH v2] kernel/ucounts: expose count of inotify watches in use |
| |
On Thu, Apr 25, 2019 at 10:07 PM Andrew Morton <akpm@linux-foundation.org> wrote: > > On Fri, 1 Feb 2019 21:39:59 +0100 Albert Vaca Cintora <albertvaka@gmail.com> wrote: > > > Adds a readonly 'current_inotify_watches' entry to the user sysctl table. > > The handler for this entry is a custom function that ends up calling > > proc_dointvec. Said sysctl table already contains 'max_inotify_watches' > > and it gets mounted under /proc/sys/user/. > > > > Inotify watches are a finite resource, in a similar way to available file > > descriptors. The motivation for this patch is to be able to set up > > monitoring and alerting before an application starts failing because > > it runs out of inotify watches. > > Matthias said "Albert found this problem while working on montitoring > software, so it fixes a real problem out there", so please include full > details of the problem which you encountered so that we are better able > to understand the value of the patch. >
This is an important metric to track as a sysadmin. Currently, monitoring software have to workaround the lack of a single metric by iterating all the file descriptors for all processes and checking which ones are inotify watches [1].
If this seems enough justification to you, please say so and I will submit a patch v3 with the requested implementation changes.
[1] https://github.com/prometheus/node_exporter/blob/master/text_collector_examples/inotify-instances
Albert
| |