* [PATCH] Increase limit of max_user_watches from 1/25 to 1/16
@ 2021-01-20 13:02 Eric Curtin
2021-01-20 13:39 ` Eric Curtin
0 siblings, 1 reply; 2+ messages in thread
From: Eric Curtin @ 2021-01-20 13:02 UTC (permalink / raw)
Cc: ericcurtin17, Jonathan Corbet, Alexander Viro,
Alexander A. Klimov, open list:DOCUMENTATION, open list,
open list:FILESYSTEMS (VFS and infrastructure)
The current default value for max_user_watches is the 1/16 (6.25%) of
the available low memory, divided for the "watch" cost in bytes.
Tools like inotify-tools and visual studio code, seem to hit these
limits a little to easy.
Also amending the documentation, it referred to an old value for this.
Signed-off-by: Eric Curtin <ericcurtin17@gmail.com>
---
Documentation/admin-guide/sysctl/fs.rst | 4 ++--
fs/eventpoll.c | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/Documentation/admin-guide/sysctl/fs.rst b/Documentation/admin-guide/sysctl/fs.rst
index f48277a0a850..f7fe45e69c41 100644
--- a/Documentation/admin-guide/sysctl/fs.rst
+++ b/Documentation/admin-guide/sysctl/fs.rst
@@ -380,5 +380,5 @@ This configuration option sets the maximum number of "watches" that are
allowed for each user.
Each "watch" costs roughly 90 bytes on a 32bit kernel, and roughly 160 bytes
on a 64bit one.
-The current default value for max_user_watches is the 1/32 of the available
-low memory, divided for the "watch" cost in bytes.
+The current default value for max_user_watches is the 1/16 (6.25%) of the
+available low memory, divided for the "watch" cost in bytes.
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index a829af074eb5..de9ef8f6d0b2 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -2352,9 +2352,9 @@ static int __init eventpoll_init(void)
si_meminfo(&si);
/*
- * Allows top 4% of lomem to be allocated for epoll watches (per user).
+ * Allows top 6.25% of lomem to be allocated for epoll watches (per user).
*/
- max_user_watches = (((si.totalram - si.totalhigh) / 25) << PAGE_SHIFT) /
+ max_user_watches = (((si.totalram - si.totalhigh) / 16) << PAGE_SHIFT) /
EP_ITEM_COST;
BUG_ON(max_user_watches < 0);
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] Increase limit of max_user_watches from 1/25 to 1/16
2021-01-20 13:02 [PATCH] Increase limit of max_user_watches from 1/25 to 1/16 Eric Curtin
@ 2021-01-20 13:39 ` Eric Curtin
0 siblings, 0 replies; 2+ messages in thread
From: Eric Curtin @ 2021-01-20 13:39 UTC (permalink / raw)
Cc: Jonathan Corbet, Alexander Viro, Alexander A. Klimov,
open list:DOCUMENTATION, open list,
open list:FILESYSTEMS (VFS and infrastructure)
On Wed, 20 Jan 2021 at 13:02, Eric Curtin <ericcurtin17@gmail.com> wrote:
>
> The current default value for max_user_watches is the 1/16 (6.25%) of
> the available low memory, divided for the "watch" cost in bytes.
>
> Tools like inotify-tools and visual studio code, seem to hit these
> limits a little to easy.
>
> Also amending the documentation, it referred to an old value for this.
>
> Signed-off-by: Eric Curtin <ericcurtin17@gmail.com>
> ---
> Documentation/admin-guide/sysctl/fs.rst | 4 ++--
> fs/eventpoll.c | 4 ++--
> 2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/admin-guide/sysctl/fs.rst b/Documentation/admin-guide/sysctl/fs.rst
> index f48277a0a850..f7fe45e69c41 100644
> --- a/Documentation/admin-guide/sysctl/fs.rst
> +++ b/Documentation/admin-guide/sysctl/fs.rst
> @@ -380,5 +380,5 @@ This configuration option sets the maximum number of "watches" that are
> allowed for each user.
> Each "watch" costs roughly 90 bytes on a 32bit kernel, and roughly 160 bytes
> on a 64bit one.
> -The current default value for max_user_watches is the 1/32 of the available
> -low memory, divided for the "watch" cost in bytes.
> +The current default value for max_user_watches is the 1/16 (6.25%) of the
> +available low memory, divided for the "watch" cost in bytes.
> diff --git a/fs/eventpoll.c b/fs/eventpoll.c
> index a829af074eb5..de9ef8f6d0b2 100644
> --- a/fs/eventpoll.c
> +++ b/fs/eventpoll.c
> @@ -2352,9 +2352,9 @@ static int __init eventpoll_init(void)
>
> si_meminfo(&si);
> /*
> - * Allows top 4% of lomem to be allocated for epoll watches (per user).
> + * Allows top 6.25% of lomem to be allocated for epoll watches (per user).
> */
> - max_user_watches = (((si.totalram - si.totalhigh) / 25) << PAGE_SHIFT) /
> + max_user_watches = (((si.totalram - si.totalhigh) / 16) << PAGE_SHIFT) /
> EP_ITEM_COST;
> BUG_ON(max_user_watches < 0);
>
> --
> 2.25.1
>
Please ignore this, this is the wrong limit (an epoll one), I sent
another patch just
to update the documentation to be correct. Weiman Long already kindly solved the
issue in 92890123749bafc317bbfacbe0a62ce08d78efb7
Separate patch is titled "[PATCH] Update
Documentation/admin-guide/sysctl/fs.rst"
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