linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Guenter Roeck <linux@roeck-us.net>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	Anton Blanchard <anton@ozlabs.org>
Subject: Re: [PATCH v1] fs/epoll: use a per-cpu counter for user's watches count
Date: Wed, 4 Aug 2021 08:22:22 -0700	[thread overview]
Message-ID: <20210804152222.GA3717568@roeck-us.net> (raw)
In-Reply-To: <20210802032013.2751916-1-npiggin@gmail.com>

On Mon, Aug 02, 2021 at 01:20:13PM +1000, Nicholas Piggin wrote:
> This counter tracks the number of watches a user has, to compare against
> the 'max_user_watches' limit. This causes a scalability bottleneck on
> SPECjbb2015 on large systems as there is only one user. Changing to a
> per-cpu counter increases throughput of the benchmark by about 30% on a
> 16-socket, > 1000 thread system.
> 
> Reported-by: Anton Blanchard <anton@ozlabs.org>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

With all tinyconfig builds (and all other builds with CONFIG_EPOLL=n),
this patch results in:

kernel/user.c: In function 'free_user':
kernel/user.c:141:35: error: 'struct user_struct' has no member named 'epoll_watches'
  141 |         percpu_counter_destroy(&up->epoll_watches);
      |                                   ^~
kernel/user.c: In function 'alloc_uid':
kernel/user.c:189:45: error: 'struct user_struct' has no member named 'epoll_watches'
  189 |                 if (percpu_counter_init(&new->epoll_watches, 0, GFP_KERNEL)) {
      |                                             ^~
kernel/user.c:203:52: error: 'struct user_struct' has no member named 'epoll_watches'
  203 |                         percpu_counter_destroy(&new->epoll_watches);
      |                                                    ^~
kernel/user.c: In function 'uid_cache_init':
kernel/user.c:225:43: error: 'struct user_struct' has no member named 'epoll_watches'
  225 |         if (percpu_counter_init(&root_user.epoll_watches, 0, GFP_KERNEL))
      |                                           ^

Guenter

  reply	other threads:[~2021-08-04 15:22 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02  3:20 Nicholas Piggin
2021-08-04 15:22 ` Guenter Roeck [this message]
2021-08-04 19:06   ` Randy Dunlap

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210804152222.GA3717568@roeck-us.net \
    --to=linux@roeck-us.net \
    --cc=akpm@linux-foundation.org \
    --cc=anton@ozlabs.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=npiggin@gmail.com \
    --cc=viro@zeniv.linux.org.uk \
    --subject='Re: [PATCH v1] fs/epoll: use a per-cpu counter for user'\''s watches count' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).