linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Zhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	 Tyler Hicks <tyhicks@linux.microsoft.com>,
	linux-mm <linux-mm@kvack.org>,
	 LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] mm: KSM: fix ksm_run data type
Date: Thu, 15 Jul 2021 15:06:15 -0400	[thread overview]
Message-ID: <CA+CK2bD8b9S7PZ8TS+vWTCwBY1h_51wQ5PrvCNNkGKO4r6E2cw@mail.gmail.com> (raw)
In-Reply-To: <CA+CK2bBqFr+_jxr2KU4DWv7GmOztfP8Lc+dKjy=YeUDvotyoBQ@mail.gmail.com>

> > > /sys/kernel/mm/ksm/run
> > >
> > > run: write 0 to disable ksm, read 0 while ksm is disabled.
> > >
> > > - write 1 to run ksm, read 1 while ksm is running.
> > > - write 2 to disable ksm and unmerge all its pages.
> >
> > The document is out of date then as it does not mention 'offline'.
>
> The offline mode cannot be set externally.
>
> In run_store()
>    if (flags > KSM_RUN_UNMERGE)
>       return -EINVAL;

However, I see that KSM_RUN_OFFLINE is visible via run_show(), so yes
doc should be updated. And, yes it becomes a bitfield from the user
perspective.

>
> >
> > Also, why does the call to kstrtouint() specify base 10?  If it is a
> > bitmap, then permitting 0x [1] is more natural.  I would expect to see
> > base 0 there.
>
> Users can only write 0, 1, or 2, it is not a bitmap from the user's
> perspective as the user cannot write: '3' . But, I think it is
> somewhat weird that ksm_run is used as a bitmap internally with
> KSM_RUN_OFFLINE = 4.
>
> Imo, KSM_RUN_OFFLINE should be placed in a separate boolean from "ksm_run".
>
> >
> > [1] or even 0b, although I see that _parse_integer_fixup_radix does not
> > support the 0b notation.


  reply	other threads:[~2021-07-15 19:06 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-15 18:00 [PATCH 0/2] mm: KSM: fix data types Zhansaya Bagdauletkyzy
2021-07-15 18:01 ` [PATCH 1/2] mm: KSM: fix ksm_run data type Zhansaya Bagdauletkyzy
2021-07-15 18:10   ` Pavel Tatashin
2021-07-15 18:17   ` Matthew Wilcox
2021-07-15 18:21     ` Pavel Tatashin
2021-07-15 18:30       ` Matthew Wilcox
2021-07-15 18:57         ` Pavel Tatashin
2021-07-15 19:06           ` Pavel Tatashin [this message]
2021-07-15 18:01 ` [PATCH 2/2] mm: KSM: fix " Zhansaya Bagdauletkyzy
2021-07-15 18:10   ` Pavel Tatashin
2021-07-16  4:42     ` Zhansaya Bagdauletkyzy

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=CA+CK2bD8b9S7PZ8TS+vWTCwBY1h_51wQ5PrvCNNkGKO4r6E2cw@mail.gmail.com \
    --to=pasha.tatashin@soleen.com \
    --cc=akpm@linux-foundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=tyhicks@linux.microsoft.com \
    --cc=willy@infradead.org \
    --cc=zhansayabagdaulet@gmail.com \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
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).