From: Matthew Wilcox <willy@infradead.org>
To: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
Andrew Morton <akpm@linux-foundation.org>,
linux-doc@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 7/7] docs/core-api: mm-api: add section about GFP flags
Date: Thu, 26 Jul 2018 08:36:05 -0700 [thread overview]
Message-ID: <20180726153605.GB27612@bombadil.infradead.org> (raw)
In-Reply-To: <20180726151852.GF8477@rapoport-lnx>
On Thu, Jul 26, 2018 at 06:18:53PM +0300, Mike Rapoport wrote:
> On Thu, Jul 26, 2018 at 04:20:39PM +0200, Michal Hocko wrote:
> > > Functions which need to allocate memory often use GFP flags to express
> > > how that memory should be allocated. The GFP acronym stands for "get
> > > free pages", the underlying memory allocation function.
> >
> > OK.
> >
> > > Not every GFP
> > > flag is allowed to every function which may allocate memory. Most
> > > users will want to use a plain ``GFP_KERNEL`` or ``GFP_ATOMIC``.
> >
> > Or rather than mentioning the two just use "Useful GFP flag
> > combinations" comment segment from gfp.h
>
> The comment there includes GFP_DMA, GFP_NOIO etc so I'd prefer Matthew's
> version and maybe even omit GFP_ATOMIC from it.
I'm totally OK with that.
> Some grepping shows that roughly 80% of allocations are GFP_KERNEL, 12% are
> GFP_ATOMIC and ... I didn't count the usage of other flags ;-)
;-) You'll find a lot of GFP_NOFS and GFP_NOIO in the filesystem/block
code ...
next prev parent reply other threads:[~2018-07-26 15:36 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-26 12:21 [PATCH v2 0/7] memory management documentation updates Mike Rapoport
2018-07-26 12:21 ` [PATCH v2 1/7] mm/util: make strndup_user description a kernel-doc comment Mike Rapoport
2018-07-26 12:21 ` [PATCH v2 2/7] mm/util: add kernel-doc for kvfree Mike Rapoport
2018-07-26 12:21 ` [PATCH v2 3/7] docs/core-api: kill trailing whitespace in kernel-api.rst Mike Rapoport
2018-07-26 12:21 ` [PATCH v2 4/7] docs/core-api: move *{str,mem}dup* to "String Manipulation" Mike Rapoport
2018-07-26 12:22 ` [PATCH v2 5/7] docs/core-api: split memory management API to a separate file Mike Rapoport
2018-07-26 12:22 ` [PATCH v2 6/7] docs/mm: make GFP flags descriptions usable as kernel-doc Mike Rapoport
2018-07-26 12:22 ` [PATCH v2 7/7] docs/core-api: mm-api: add section about GFP flags Mike Rapoport
2018-07-26 13:01 ` Matthew Wilcox
2018-07-26 14:20 ` Michal Hocko
2018-07-26 15:18 ` Mike Rapoport
2018-07-26 15:36 ` Matthew Wilcox [this message]
2018-07-26 16:41 ` Michal Hocko
2018-07-26 17:24 ` Mike Rapoport
2018-07-26 15:29 ` Mike Rapoport
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=20180726153605.GB27612@bombadil.infradead.org \
--to=willy@infradead.org \
--cc=akpm@linux-foundation.org \
--cc=corbet@lwn.net \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=rppt@linux.vnet.ibm.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).