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From: Matthew Wilcox <willy@infradead.org>
To: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>, Michal Hocko <mhocko@kernel.org>,
	Linux-MM <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Michal Hocko <mhocko@suse.com>,
	Greg KH <gregkh@linuxfoundation.org>
Subject: Re: [RFC PATCH] mm: silence soft lockups from unlock_page
Date: Fri, 7 Aug 2020 20:35:10 +0100	[thread overview]
Message-ID: <20200807193510.GG17456@casper.infradead.org> (raw)
In-Reply-To: <alpine.LSU.2.11.2008071047510.1239@eggly.anvils>

On Fri, Aug 07, 2020 at 11:41:09AM -0700, Hugh Dickins wrote:
> My home testing was, effectively, on top of c6fe44d96fc1 (v5.8 plus
> your two patches): I did not have in the io_uring changes from the
> current tree. In glancing there, I noticed one new and one previous
> instance of SetPageWaiters() *after* __add_wait_queue_entry_tail():
> are those correct?

By the way, don't do any performance testing on current Linus tree.
This commit:

commit 37f4a24c2469a10a4c16c641671bd766e276cf9f (refs/bisect/bad)
Author: Ming Lei <ming.lei@redhat.com>
Date:   Tue Jun 30 22:03:57 2020 +0800

    blk-mq: centralise related handling into blk_mq_get_driver_tag
    
    Move .nr_active update and request assignment into blk_mq_get_driver_tag(),
    all are good to do during getting driver tag.
    
    Meantime blk-flush related code is simplified and flush request needn't
    to update the request table manually any more.
    
    Signed-off-by: Ming Lei <ming.lei@redhat.com>
    Cc: Christoph Hellwig <hch@infradead.org>
    Signed-off-by: Jens Axboe <axboe@kernel.dk>

slows everything down, at least on my test qemu system.  Seems like it's
losing block queue tags.


  parent reply	other threads:[~2020-08-07 19:35 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-21  6:32 [RFC PATCH] mm: silence soft lockups from unlock_page Michal Hocko
     [not found] ` <FCC3EB2D-9F11-4E9E-88F4-40B2926B35CC@lca.pw>
2020-07-21 11:25   ` Michal Hocko
     [not found]     ` <664A07B6-DBCD-4520-84F1-241A4E7A339F@lca.pw>
2020-07-21 12:17       ` Michal Hocko
     [not found]         ` <20200721132343.GA4261@lca.pw>
2020-07-21 13:38           ` Michal Hocko
2020-07-21 14:17 ` Chris Down
2020-07-21 15:00   ` Michal Hocko
2020-07-21 15:33 ` Linus Torvalds
2020-07-21 15:49   ` Michal Hocko
2020-07-22 18:29   ` Linus Torvalds
2020-07-22 21:29     ` Hugh Dickins
2020-07-22 22:10       ` Linus Torvalds
2020-07-22 23:42         ` Linus Torvalds
2020-07-23  0:23           ` Linus Torvalds
2020-07-23 12:47           ` Oleg Nesterov
2020-07-23 17:32             ` Linus Torvalds
2020-07-23 18:01               ` Oleg Nesterov
2020-07-23 18:22                 ` Linus Torvalds
2020-07-23 19:03                   ` Linus Torvalds
2020-07-24 14:45                     ` Oleg Nesterov
2020-07-23 20:03               ` Linus Torvalds
2020-07-23 23:11                 ` Hugh Dickins
2020-07-23 23:43                   ` Linus Torvalds
2020-07-24  0:07                     ` Hugh Dickins
2020-07-24  0:46                       ` Linus Torvalds
2020-07-24  3:45                         ` Hugh Dickins
2020-07-24 15:24                     ` Oleg Nesterov
2020-07-24 17:32                       ` Linus Torvalds
2020-07-24 23:25                         ` Linus Torvalds
2020-07-25  2:08                           ` Hugh Dickins
2020-07-25  2:46                             ` Linus Torvalds
2020-07-25 10:14                           ` Oleg Nesterov
2020-07-25 18:48                             ` Linus Torvalds
2020-07-25 19:27                               ` Oleg Nesterov
2020-07-25 19:51                                 ` Linus Torvalds
2020-07-26 13:57                                   ` Oleg Nesterov
2020-07-25 21:19                               ` Hugh Dickins
2020-07-26  4:22                                 ` Hugh Dickins
2020-07-26 20:30                                   ` Hugh Dickins
2020-07-26 20:41                                     ` Linus Torvalds
2020-07-26 22:09                                       ` Hugh Dickins
2020-07-27 19:35                                     ` Greg KH
2020-08-06  5:46                                       ` Hugh Dickins
2020-08-18 13:50                                         ` Greg KH
2020-08-06  5:21                                     ` Hugh Dickins
2020-08-06 17:07                                       ` Linus Torvalds
2020-08-06 18:00                                         ` Matthew Wilcox
2020-08-06 18:32                                           ` Linus Torvalds
2020-08-07 18:41                                             ` Hugh Dickins
2020-08-07 19:07                                               ` Linus Torvalds
2020-08-07 19:35                                               ` Matthew Wilcox [this message]
2020-08-03 13:14                           ` Michal Hocko
2020-08-03 17:56                             ` Linus Torvalds
2020-07-25  9:39                         ` Oleg Nesterov
2020-07-23  8:03     ` Michal Hocko

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