From: Lorenzo Stoakes <lstoakes@gmail.com>
To: linux-mm@kvack.org
Cc: "Linus Torvalds" <torvalds@linux-foundation.org>,
"Michal Hocko" <mhocko@kernel.org>, "Jan Kara" <jack@suse.cz>,
"Hugh Dickins" <hughd@google.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Rik van Riel" <riel@redhat.com>,
"Mel Gorman" <mgorman@techsingularity.net>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: remove unnecessary __get_user_pages_unlocked() calls
Date: Wed, 26 Oct 2016 08:59:52 +0100 [thread overview]
Message-ID: <20161026075952.GA30977@lucifer> (raw)
In-Reply-To: <20161025233609.5601-1-lstoakes@gmail.com>
On Wed, Oct 26, 2016 at 12:36:09AM +0100, Lorenzo Stoakes wrote:
> In hva_to_pfn_slow() we are able to replace __get_user_pages_unlocked() with
> get_user_pages_unlocked() since we can now pass gup_flags.
>
> In async_pf_execute() we need to pass different tsk, mm arguments so
> get_user_pages_remote() is the sane replacement here (having added manual
> acquisition and release of mmap_sem.)
>
> Since we pass a NULL pages parameter the subsequent call to
> __get_user_pages_locked() will have previously bailed any attempt at
> VM_FAULT_RETRY, so we do not change this behaviour by using
> get_user_pages_remote() which does not invoke VM_FAULT_RETRY logic at all.
>
> Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Note that the use of get_user_pages_remote() in async_pf_execute() reintroduces
the use of the FOLL_TOUCH flag - I don't think this is a problem as this flag
was dropped by 1e987790 ("mm/gup: Introduce get_user_pages_remote()") which
states 'Without protection keys, this patch should not change any behavior', so
I don't think this was intentional.
WARNING: multiple messages have this Message-ID (diff)
From: Lorenzo Stoakes <lstoakes@gmail.com>
To: linux-mm@kvack.org
Cc: "Linus Torvalds" <torvalds@linux-foundation.org>,
"Michal Hocko" <mhocko@kernel.org>, "Jan Kara" <jack@suse.cz>,
"Hugh Dickins" <hughd@google.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Rik van Riel" <riel@redhat.com>,
"Mel Gorman" <mgorman@techsingularity.net>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: remove unnecessary __get_user_pages_unlocked() calls
Date: Wed, 26 Oct 2016 08:59:52 +0100 [thread overview]
Message-ID: <20161026075952.GA30977@lucifer> (raw)
In-Reply-To: <20161025233609.5601-1-lstoakes@gmail.com>
On Wed, Oct 26, 2016 at 12:36:09AM +0100, Lorenzo Stoakes wrote:
> In hva_to_pfn_slow() we are able to replace __get_user_pages_unlocked() with
> get_user_pages_unlocked() since we can now pass gup_flags.
>
> In async_pf_execute() we need to pass different tsk, mm arguments so
> get_user_pages_remote() is the sane replacement here (having added manual
> acquisition and release of mmap_sem.)
>
> Since we pass a NULL pages parameter the subsequent call to
> __get_user_pages_locked() will have previously bailed any attempt at
> VM_FAULT_RETRY, so we do not change this behaviour by using
> get_user_pages_remote() which does not invoke VM_FAULT_RETRY logic at all.
>
> Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Note that the use of get_user_pages_remote() in async_pf_execute() reintroduces
the use of the FOLL_TOUCH flag - I don't think this is a problem as this flag
was dropped by 1e987790 ("mm/gup: Introduce get_user_pages_remote()") which
states 'Without protection keys, this patch should not change any behavior', so
I don't think this was intentional.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-10-26 7:59 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-25 23:36 [PATCH] mm: remove unnecessary __get_user_pages_unlocked() calls Lorenzo Stoakes
2016-10-25 23:36 ` Lorenzo Stoakes
2016-10-25 23:46 ` Lorenzo Stoakes
2016-10-25 23:46 ` Lorenzo Stoakes
2016-10-26 9:15 ` Michal Hocko
2016-10-26 9:15 ` Michal Hocko
2016-10-26 9:39 ` Lorenzo Stoakes
2016-10-26 9:39 ` Lorenzo Stoakes
2016-10-26 9:54 ` Michal Hocko
2016-10-26 9:54 ` Michal Hocko
2016-10-26 7:59 ` Lorenzo Stoakes [this message]
2016-10-26 7:59 ` Lorenzo Stoakes
2016-10-26 9:07 ` Michal Hocko
2016-10-26 9:07 ` Michal Hocko
2016-10-26 9:12 ` Michal Hocko
2016-10-26 9:12 ` Michal Hocko
2016-10-26 9:25 ` [PATCH v2] " Lorenzo Stoakes
2016-10-26 9:25 ` Lorenzo Stoakes
2016-10-27 0:12 ` Andrew Morton
2016-10-27 0:12 ` Andrew Morton
2016-10-27 7:06 ` Lorenzo Stoakes
2016-10-27 7:06 ` Lorenzo Stoakes
2016-10-27 9:27 ` Paolo Bonzini
2016-10-27 9:27 ` Paolo Bonzini
2016-10-27 9:32 ` Lorenzo Stoakes
2016-10-27 9:32 ` Lorenzo Stoakes
2016-10-27 9:35 ` Paolo Bonzini
2016-10-27 9:35 ` Paolo Bonzini
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=20161026075952.GA30977@lucifer \
--to=lstoakes@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=dave.hansen@linux.intel.com \
--cc=hughd@google.com \
--cc=jack@suse.cz \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@techsingularity.net \
--cc=mhocko@kernel.org \
--cc=pbonzini@redhat.com \
--cc=riel@redhat.com \
--cc=rkrcmar@redhat.com \
--cc=torvalds@linux-foundation.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.