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From: Baoquan He <bhe@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	gopakumarr@vmware.com, rppt@kernel.org, david@redhat.com
Subject: Re: [PATCH v2 0/5] Fix the incorrect memmep defer init handling and do some cleanup
Date: Wed, 23 Dec 2020 10:05:34 +0800	[thread overview]
Message-ID: <20201223020534.GA2205@MiWiFi-R3L-srv> (raw)
In-Reply-To: <20201222174658.a2d08ca723a20587467792d9@linux-foundation.org>

On 12/22/20 at 05:46pm, Andrew Morton wrote:
> On Sun, 20 Dec 2020 16:27:49 +0800 Baoquan He <bhe@redhat.com> wrote:
> 
> > VMware reported the performance regression during memmap_init() invocation.
> > And they bisected to commit 73a6e474cb376 ("mm: memmap_init: iterate over
> > memblock regions rather that check each PFN") causing it.
> > 
> > https://lore.kernel.org/linux-mm/DM6PR05MB52921FF90FA01CC337DD23A1A4080@DM6PR05MB5292.namprd05.prod.outlook.com/
> > 
> > After investigation, it's caused by incorrect memmap init defer handling
> > in memmap_init_zone() after commit 73a6e474cb376. The current
> > memmap_init_zone() only handle one memory region of one zone, while
> > memmap_init() iterates over all its memory regions and pass them one by
> > one into memmap_init_zone() to handle.
> > 
> > So in this patchset, patch 1/5 fixes the bug observed by VMware. Patch
> > 2~5/5 clean up codes.
> > accordingly.
> 
> This series doesn't apply well to current mainline (plus, perhaps,
> material which I sent to Linus today).
> 
> So please check all that against mainline in a day or so, refresh,
> retest and resend.
> 
> Please separate the fix for the performance regression (1/5) into a
> single standalone patch, ready for -stable backporting.  And then a
> separate 4-patch series with the cleanups for a 5.11 merge.

Sure, doing now. 

By the way, when sending patches to linux-mm ML, which branch should I
rebase them on? I usually take your akpm/master as base, thought this
will make your patch picking easier. Seems my understanding is not true,
akpm/master is changed very soon, we should always base patch on linus's
master branch, whether patch is sending to linux-mm or not, right?

Thanks
Baoquan



  reply	other threads:[~2020-12-23  2:05 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-20  8:27 [PATCH v2 0/5] Fix the incorrect memmep defer init handling and do some cleanup Baoquan He
2020-12-20  8:27 ` [PATCH v2 1/5] mm: memmap defer init dosn't work as expected Baoquan He
2020-12-21  6:32   ` Mike Rapoport
2020-12-20  8:27 ` [PATCH v2 2/5] mm: rename memmap_init() and memmap_init_zone() Baoquan He
2020-12-21  6:33   ` Mike Rapoport
2020-12-20  8:27 ` [PATCH v2 3/5] mm: simplify parater of function memmap_init_zone() Baoquan He
2020-12-21  6:34   ` Mike Rapoport
2020-12-20  8:27 ` [PATCH v2 4/5] mm: simplify parameter of setup_usemap() Baoquan He
2020-12-21  6:34   ` Mike Rapoport
2020-12-20  8:27 ` [PATCH v2 5/5] mm: remove unneeded local variable in free_area_init_core Baoquan He
2020-12-21  6:35   ` Mike Rapoport
2020-12-23  1:46 ` [PATCH v2 0/5] Fix the incorrect memmep defer init handling and do some cleanup Andrew Morton
2020-12-23  2:05   ` Baoquan He [this message]
2020-12-23  8:12     ` Baoquan He

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