From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>,
"Huang, Ying" <ying.huang@intel.com>,
Dave Chinner <david@fromorbit.com>,
LKML <linux-kernel@vger.kernel.org>,
Bob Peterson <rpeterso@redhat.com>,
Wu Fengguang <fengguang.wu@intel.com>, LKP <lkp@01.org>
Subject: Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression
Date: Thu, 11 Aug 2016 23:16:35 +0100 [thread overview]
Message-ID: <20160811221634.GU2356@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CA+55aFwPqsxBquvAdgvEgE+stgvMi4ecw26zP7Q1Xi3N6fCRwQ@mail.gmail.com>
On Thu, Aug 11, 2016 at 01:35:00PM -0700, Linus Torvalds wrote:
> The thing is, iov_iter_copy_from_user_atomic() doesn't itself enforce
> non-blocking user accesses, it depends on the caller blocking page
> faults.
Huh? The very first thing it does is
char *kaddr = kmap_atomic(page), *p = kaddr + offset;
If _that_ does not disable pagefaults, we are very deep in shit. AFAICS,
all instances of that sucker do disable those, including the non-highmem
default (it's
static inline void *kmap_atomic(struct page *page)
{
preempt_disable();
pagefault_disable();
return page_address(page);
}
)
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@ZenIV.linux.org.uk>
To: lkp@lists.01.org
Subject: Re: [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression
Date: Thu, 11 Aug 2016 23:16:35 +0100 [thread overview]
Message-ID: <20160811221634.GU2356@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CA+55aFwPqsxBquvAdgvEgE+stgvMi4ecw26zP7Q1Xi3N6fCRwQ@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 646 bytes --]
On Thu, Aug 11, 2016 at 01:35:00PM -0700, Linus Torvalds wrote:
> The thing is, iov_iter_copy_from_user_atomic() doesn't itself enforce
> non-blocking user accesses, it depends on the caller blocking page
> faults.
Huh? The very first thing it does is
char *kaddr = kmap_atomic(page), *p = kaddr + offset;
If _that_ does not disable pagefaults, we are very deep in shit. AFAICS,
all instances of that sucker do disable those, including the non-highmem
default (it's
static inline void *kmap_atomic(struct page *page)
{
preempt_disable();
pagefault_disable();
return page_address(page);
}
)
next prev parent reply other threads:[~2016-08-11 22:16 UTC|newest]
Thread overview: 219+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-09 14:33 [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression kernel test robot
2016-08-09 14:33 ` kernel test robot
2016-08-10 18:24 ` [lkp] " Linus Torvalds
2016-08-10 18:24 ` Linus Torvalds
2016-08-10 23:08 ` [lkp] " Dave Chinner
2016-08-10 23:08 ` Dave Chinner
2016-08-10 23:51 ` [lkp] " Linus Torvalds
2016-08-10 23:51 ` Linus Torvalds
2016-08-10 23:58 ` [LKP] [lkp] " Huang, Ying
2016-08-10 23:58 ` Huang, Ying
2016-08-11 0:11 ` [LKP] [lkp] " Huang, Ying
2016-08-11 0:11 ` Huang, Ying
2016-08-11 0:23 ` [LKP] [lkp] " Linus Torvalds
2016-08-11 0:23 ` Linus Torvalds
2016-08-11 0:33 ` [LKP] [lkp] " Huang, Ying
2016-08-11 0:33 ` Huang, Ying
2016-08-11 1:00 ` [LKP] [lkp] " Linus Torvalds
2016-08-11 1:00 ` Linus Torvalds
2016-08-11 4:46 ` [LKP] [lkp] " Dave Chinner
2016-08-11 4:46 ` Dave Chinner
2016-08-15 17:22 ` [LKP] [lkp] " Huang, Ying
2016-08-15 17:22 ` Huang, Ying
2016-08-16 0:08 ` [LKP] [lkp] " Dave Chinner
2016-08-16 0:08 ` Dave Chinner
2016-08-11 15:57 ` [LKP] [lkp] " Christoph Hellwig
2016-08-11 15:57 ` Christoph Hellwig
2016-08-11 16:55 ` [LKP] [lkp] " Linus Torvalds
2016-08-11 16:55 ` Linus Torvalds
2016-08-11 17:51 ` [LKP] [lkp] " Huang, Ying
2016-08-11 17:51 ` Huang, Ying
2016-08-11 19:51 ` [LKP] [lkp] " Linus Torvalds
2016-08-11 19:51 ` Linus Torvalds
2016-08-11 20:00 ` [LKP] [lkp] " Christoph Hellwig
2016-08-11 20:00 ` Christoph Hellwig
2016-08-11 20:35 ` [LKP] [lkp] " Linus Torvalds
2016-08-11 20:35 ` Linus Torvalds
2016-08-11 22:16 ` Al Viro [this message]
2016-08-11 22:16 ` Al Viro
2016-08-11 22:30 ` [LKP] [lkp] " Linus Torvalds
2016-08-11 22:30 ` Linus Torvalds
2016-08-11 21:16 ` [LKP] [lkp] " Huang, Ying
2016-08-11 21:16 ` Huang, Ying
2016-08-11 21:40 ` [LKP] [lkp] " Linus Torvalds
2016-08-11 21:40 ` Linus Torvalds
2016-08-11 22:08 ` [LKP] [lkp] " Christoph Hellwig
2016-08-11 22:08 ` Christoph Hellwig
2016-08-12 0:54 ` [LKP] [lkp] " Dave Chinner
2016-08-12 0:54 ` Dave Chinner
2016-08-12 2:23 ` [LKP] [lkp] " Dave Chinner
2016-08-12 2:23 ` Dave Chinner
2016-08-12 2:32 ` [LKP] [lkp] " Linus Torvalds
2016-08-12 2:32 ` Linus Torvalds
2016-08-12 2:52 ` [LKP] [lkp] " Christoph Hellwig
2016-08-12 2:52 ` Christoph Hellwig
2016-08-12 3:20 ` [LKP] [lkp] " Linus Torvalds
2016-08-12 3:20 ` Linus Torvalds
2016-08-12 4:16 ` [LKP] [lkp] " Dave Chinner
2016-08-12 4:16 ` Dave Chinner
2016-08-12 5:02 ` [LKP] [lkp] " Linus Torvalds
2016-08-12 5:02 ` Linus Torvalds
2016-08-12 6:04 ` [LKP] [lkp] " Dave Chinner
2016-08-12 6:04 ` Dave Chinner
2016-08-12 6:29 ` [LKP] [lkp] " Ye Xiaolong
2016-08-12 6:29 ` Ye Xiaolong
2016-08-12 8:51 ` [LKP] [lkp] " Ye Xiaolong
2016-08-12 8:51 ` Ye Xiaolong
2016-08-12 10:02 ` [LKP] [lkp] " Dave Chinner
2016-08-12 10:02 ` Dave Chinner
2016-08-12 10:43 ` Fengguang Wu
2016-08-12 10:43 ` Fengguang Wu
2016-08-13 0:30 ` [LKP] [lkp] " Christoph Hellwig
2016-08-13 0:30 ` Christoph Hellwig
2016-08-13 21:48 ` [LKP] [lkp] " Christoph Hellwig
2016-08-13 21:48 ` Christoph Hellwig
2016-08-13 22:07 ` [LKP] [lkp] " Fengguang Wu
2016-08-13 22:07 ` Fengguang Wu
2016-08-13 22:15 ` [LKP] [lkp] " Christoph Hellwig
2016-08-13 22:15 ` Christoph Hellwig
2016-08-13 22:51 ` [LKP] [lkp] " Fengguang Wu
2016-08-13 22:51 ` Fengguang Wu
2016-08-14 14:50 ` [LKP] [lkp] " Fengguang Wu
2016-08-14 14:50 ` Fengguang Wu
2016-08-14 16:17 ` [LKP] [lkp] " Christoph Hellwig
2016-08-14 16:17 ` Christoph Hellwig
2016-08-14 23:46 ` [LKP] [lkp] " Dave Chinner
2016-08-14 23:46 ` Dave Chinner
2016-08-14 23:57 ` [LKP] [lkp] " Fengguang Wu
2016-08-14 23:57 ` Fengguang Wu
2016-08-15 14:14 ` [LKP] [lkp] " Fengguang Wu
2016-08-15 14:14 ` Fengguang Wu
2016-08-15 21:22 ` [LKP] [lkp] " Dave Chinner
2016-08-15 21:22 ` Dave Chinner
2016-08-16 12:20 ` [LKP] [lkp] " Fengguang Wu
2016-08-16 12:20 ` Fengguang Wu
2016-08-15 20:30 ` [LKP] [lkp] " Huang, Ying
2016-08-15 20:30 ` Huang, Ying
2016-08-22 22:09 ` [LKP] [lkp] " Huang, Ying
2016-08-22 22:09 ` Huang, Ying
2016-09-26 6:25 ` [LKP] [lkp] " Huang, Ying
2016-09-26 6:25 ` Huang, Ying
2016-09-26 14:55 ` [LKP] [lkp] " Christoph Hellwig
2016-09-26 14:55 ` Christoph Hellwig
2016-09-27 0:52 ` [LKP] [lkp] " Huang, Ying
2016-09-27 0:52 ` Huang, Ying
2016-08-16 13:25 ` [LKP] [lkp] " Fengguang Wu
2016-08-16 13:25 ` Fengguang Wu
2016-08-13 23:32 ` [LKP] [lkp] " Dave Chinner
2016-08-13 23:32 ` Dave Chinner
2016-08-12 2:27 ` [LKP] [lkp] " Linus Torvalds
2016-08-12 2:27 ` Linus Torvalds
2016-08-12 3:56 ` [LKP] [lkp] " Dave Chinner
2016-08-12 3:56 ` Dave Chinner
2016-08-12 18:03 ` [LKP] [lkp] " Linus Torvalds
2016-08-12 18:03 ` Linus Torvalds
2016-08-13 23:58 ` [LKP] [lkp] " Fengguang Wu
2016-08-13 23:58 ` Fengguang Wu
2016-08-15 0:48 ` [LKP] [lkp] " Dave Chinner
2016-08-15 0:48 ` Dave Chinner
2016-08-15 1:37 ` [LKP] [lkp] " Linus Torvalds
2016-08-15 1:37 ` Linus Torvalds
2016-08-15 2:28 ` [LKP] [lkp] " Dave Chinner
2016-08-15 2:28 ` Dave Chinner
2016-08-15 2:53 ` [LKP] [lkp] " Linus Torvalds
2016-08-15 2:53 ` Linus Torvalds
2016-08-15 5:00 ` [LKP] [lkp] " Dave Chinner
2016-08-15 5:00 ` Dave Chinner
[not found] ` <CA+55aFwva2Xffai+Eqv1Jn_NGryk3YJ2i5JoHOQnbQv6qVPAsw@mail.gmail.com>
[not found] ` <CA+55aFy14nUnJQ_GdF=j8Fa9xiH70c6fY2G3q5HQ01+8z1z3qQ@mail.gmail.com>
2016-08-15 5:12 ` Linus Torvalds
2016-08-15 22:22 ` [LKP] [lkp] " Dave Chinner
2016-08-15 22:22 ` Dave Chinner
2016-08-15 22:42 ` [LKP] [lkp] " Dave Chinner
2016-08-15 22:42 ` Dave Chinner
2016-08-15 23:20 ` [LKP] [lkp] " Linus Torvalds
2016-08-15 23:20 ` Linus Torvalds
2016-08-15 23:48 ` [LKP] [lkp] " Linus Torvalds
2016-08-15 23:48 ` Linus Torvalds
2016-08-16 0:44 ` [LKP] [lkp] " Dave Chinner
2016-08-16 0:44 ` Dave Chinner
2016-08-16 15:05 ` [LKP] [lkp] " Mel Gorman
2016-08-16 15:05 ` Mel Gorman
2016-08-16 17:47 ` [LKP] [lkp] " Linus Torvalds
2016-08-16 17:47 ` Linus Torvalds
2016-08-17 15:48 ` [LKP] [lkp] " Michal Hocko
2016-08-17 15:48 ` Michal Hocko
2016-08-17 16:42 ` [LKP] [lkp] " Michal Hocko
2016-08-17 16:42 ` Michal Hocko
2016-08-17 15:49 ` [LKP] [lkp] " Mel Gorman
2016-08-17 15:49 ` Mel Gorman
2016-08-18 0:45 ` [LKP] [lkp] " Mel Gorman
2016-08-18 0:45 ` Mel Gorman
2016-08-18 7:11 ` [LKP] [lkp] " Dave Chinner
2016-08-18 7:11 ` Dave Chinner
2016-08-18 13:24 ` [LKP] [lkp] " Mel Gorman
2016-08-18 13:24 ` Mel Gorman
2016-08-18 17:55 ` [LKP] [lkp] " Linus Torvalds
2016-08-18 17:55 ` Linus Torvalds
2016-08-18 21:19 ` [LKP] [lkp] " Dave Chinner
2016-08-18 21:19 ` Dave Chinner
2016-08-18 22:25 ` [LKP] [lkp] " Linus Torvalds
2016-08-18 22:25 ` Linus Torvalds
2016-08-19 9:00 ` [LKP] [lkp] " Michal Hocko
2016-08-19 9:00 ` Michal Hocko
2016-08-19 10:49 ` [LKP] [lkp] " Mel Gorman
2016-08-19 10:49 ` Mel Gorman
2016-08-19 23:48 ` [LKP] [lkp] " Dave Chinner
2016-08-19 23:48 ` Dave Chinner
2016-08-20 1:08 ` [LKP] [lkp] " Linus Torvalds
2016-08-20 1:08 ` Linus Torvalds
2016-08-20 12:16 ` [LKP] [lkp] " Mel Gorman
2016-08-20 12:16 ` Mel Gorman
2016-08-19 15:08 ` [LKP] [lkp] " Mel Gorman
2016-08-19 15:08 ` Mel Gorman
2016-09-01 23:32 ` [LKP] [lkp] " Dave Chinner
2016-09-01 23:32 ` Dave Chinner
2016-09-06 15:37 ` [LKP] [lkp] " Mel Gorman
2016-09-06 15:37 ` Mel Gorman
2016-09-06 15:52 ` [LKP] [lkp] " Huang, Ying
2016-09-06 15:52 ` Huang, Ying
2016-08-24 15:40 ` [LKP] [lkp] " Huang, Ying
2016-08-24 15:40 ` Huang, Ying
2016-08-25 9:37 ` [LKP] [lkp] " Mel Gorman
2016-08-25 9:37 ` Mel Gorman
2016-08-18 2:44 ` [LKP] [lkp] " Dave Chinner
2016-08-18 2:44 ` Dave Chinner
2016-08-16 0:15 ` [LKP] [lkp] " Linus Torvalds
2016-08-16 0:15 ` Linus Torvalds
2016-08-16 0:38 ` [LKP] [lkp] " Dave Chinner
2016-08-16 0:38 ` Dave Chinner
2016-08-16 0:50 ` [LKP] [lkp] " Linus Torvalds
2016-08-16 0:50 ` Linus Torvalds
2016-08-16 0:19 ` [LKP] [lkp] " Dave Chinner
2016-08-16 0:19 ` Dave Chinner
2016-08-16 1:51 ` [LKP] [lkp] " Linus Torvalds
2016-08-16 1:51 ` Linus Torvalds
2016-08-16 22:02 ` [LKP] [lkp] " Dave Chinner
2016-08-16 22:02 ` Dave Chinner
2016-08-16 23:23 ` [LKP] [lkp] " Linus Torvalds
2016-08-16 23:23 ` Linus Torvalds
2016-08-15 23:01 ` [LKP] [lkp] " Linus Torvalds
2016-08-15 23:01 ` Linus Torvalds
2016-08-16 0:17 ` [LKP] [lkp] " Dave Chinner
2016-08-16 0:17 ` Dave Chinner
2016-08-16 0:45 ` [LKP] [lkp] " Linus Torvalds
2016-08-16 0:45 ` Linus Torvalds
2016-08-15 5:03 ` [LKP] [lkp] " Ingo Molnar
2016-08-15 5:03 ` Ingo Molnar
2016-08-17 16:24 ` [LKP] [lkp] " Peter Zijlstra
2016-08-17 16:24 ` Peter Zijlstra
2016-08-15 12:58 ` [LKP] [lkp] " Fengguang Wu
2016-08-15 12:58 ` Fengguang Wu
2016-08-11 1:16 ` [LKP] [lkp] " Dave Chinner
2016-08-11 1:16 ` Dave Chinner
2016-08-11 1:32 ` [LKP] [lkp] " Dave Chinner
2016-08-11 1:32 ` Dave Chinner
2016-08-11 2:36 ` [LKP] [lkp] " Ye Xiaolong
2016-08-11 2:36 ` Ye Xiaolong
2016-08-11 3:05 ` [LKP] [lkp] " Dave Chinner
2016-08-11 3:05 ` Dave Chinner
2016-08-12 1:26 ` [LKP] [lkp] " Dave Chinner
2016-08-12 1:26 ` Dave Chinner
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