[PATCH 1/3] epoll: increase default max_user_instances to 1024

Bron Gondwana
2009-01-28T03:47:21Z

Both Postfix and Apache use an epoll instance per child, which
leads to significant scalability issues with max_user_instances
set so low. Bump the default to 1024 so medium sized sites are
not impacted.

Signed-off-by: Bron Gondwana <brong@fastmail.fm>
---
Documentation/filesystems/proc.txt | 6 +++++-
fs/eventpoll.c | 2 +-
2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index bbebc3a..4677abf 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -2237,9 +2237,13 @@ max_user_instances
------------------

This is the maximum number of epoll file descriptors that a single user can
-have open at a given time. The default value is 128, and should be enough
+have open at a given time. The default value is 1024, and should be enough
for normal users.

+If you are running a heavily loaded Postfix or Apache server, you may need
+to set this higher. Both these servers run an epoll instance per child
+process.
+
max_user_watches
----------------

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index ba2f9ec..16eb817 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1366,7 +1366,7 @@ static int __init eventpoll_init(void)
struct sysinfo si;

si_meminfo(&si);
- max_user_instances = 128;
+ max_user_instances = 1024;
max_user_watches = (((si.totalram - si.totalhigh) / 32) << PAGE_SHIFT) /
EP_ITEM_COST;

--
1.5.6.3