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From: Joel Fernandes <joel@joelfernandes.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Borislav Petkov <bp@alien8.de>,
	Brendan Gregg <bgregg@netflix.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Christian Hansen <chansen3@cisco.com>,
	dancol@google.com, fmayer@google.com,
	"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Kees Cook <keescook@chromium.org>,
	kernel-team@android.com, linux-api@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, Michal Hocko <mhocko@suse.com>,
	Mike Rapoport <rppt@linux.ibm.com>,
	minchan@kernel.org, namhyung@google.com, paulmck@linux.ibm.com,
	Robin Murphy <robin.murphy@arm.com>, Roman Gushchin <guro@fb.com>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	surenb@google.com, Thomas Gleixner <tglx@linutronix.de>,
	tkjos@google.com, Vladimir Davydov <vdavydov.dev@gmail.com>,
	Vlastimil Babka <vbabka@suse.cz>, Will Deacon <will@kernel.org>
Subject: Re: [PATCH v5 1/6] mm/page_idle: Add per-pid idle page tracking using virtual index
Date: Wed, 7 Aug 2019 16:45:30 -0400	[thread overview]
Message-ID: <20190807204530.GB90900@google.com> (raw)
In-Reply-To: <20190807130402.49c9ea8bf144d2f83bfeb353@linux-foundation.org>

On Wed, Aug 07, 2019 at 01:04:02PM -0700, Andrew Morton wrote:
> On Wed,  7 Aug 2019 13:15:54 -0400 "Joel Fernandes (Google)" <joel@joelfernandes.org> wrote:
> 
> > In Android, we are using this for the heap profiler (heapprofd) which
> > profiles and pin points code paths which allocates and leaves memory
> > idle for long periods of time. This method solves the security issue
> > with userspace learning the PFN, and while at it is also shown to yield
> > better results than the pagemap lookup, the theory being that the window
> > where the address space can change is reduced by eliminating the
> > intermediate pagemap look up stage. In virtual address indexing, the
> > process's mmap_sem is held for the duration of the access.
> 
> So is heapprofd a developer-only thing?  Is heapprofd included in
> end-user android loads?  If not then, again, wouldn't it be better to
> make the feature Kconfigurable so that Android developers can enable it
> during development then disable it for production kernels?

Almost all of this code is already configurable with
CONFIG_IDLE_PAGE_TRACKING. If you disable it, then all of this code gets
disabled.

Or are you referring to something else that needs to be made configurable?

thanks,

 - Joel


  reply	other threads:[~2019-08-07 20:45 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-07 17:15 [PATCH v5 1/6] mm/page_idle: Add per-pid idle page tracking using virtual index Joel Fernandes (Google)
2019-08-07 17:15 ` [PATCH v5 2/6] mm/page_idle: Add support for handling swapped PG_Idle pages Joel Fernandes (Google)
2019-08-13 15:04   ` Michal Hocko
2019-08-13 15:36     ` Joel Fernandes
2019-08-13 19:24       ` Konstantin Khlebnikov
2019-08-14  8:05       ` Michal Hocko
2019-08-14 16:32         ` Joel Fernandes
2019-08-14 18:36           ` Michal Hocko
2019-08-07 17:15 ` [PATCH v5 3/6] [RFC] x86: Add support for idle bit in swap PTE Joel Fernandes (Google)
2019-08-07 17:15 ` [PATCH v5 4/6] [RFC] arm64: " Joel Fernandes (Google)
2019-08-07 17:15 ` [PATCH v5 5/6] page_idle: Drain all LRU pagevec before idle tracking Joel Fernandes (Google)
2019-08-07 17:15 ` [PATCH v5 6/6] doc: Update documentation for page_idle virtual address indexing Joel Fernandes (Google)
2019-08-07 20:04 ` [PATCH v5 1/6] mm/page_idle: Add per-pid idle page tracking using virtual index Andrew Morton
2019-08-07 20:45   ` Joel Fernandes [this message]
2019-08-07 20:58     ` Andrew Morton
2019-08-07 21:31       ` Joel Fernandes
2019-08-07 21:55         ` Joel Fernandes
2019-08-08  8:00         ` Michal Hocko
2019-08-12 14:56           ` Joel Fernandes
2019-08-13  9:14             ` Michal Hocko
2019-08-13 13:51               ` Joel Fernandes
2019-08-13 14:14                 ` Michal Hocko
2019-08-13 14:45                   ` Joel Fernandes
2019-08-13 14:57                     ` Michal Hocko
2019-08-12 18:14 ` Jann Horn
2019-08-13 10:08   ` Michal Hocko
2019-08-13 14:25     ` Joel Fernandes
2019-08-13 15:19       ` Jann Horn
2019-08-13 15:29     ` Jann Horn
2019-08-13 15:34       ` Daniel Gruss
2019-08-13 19:18         ` Joel Fernandes
2019-08-14  7:56       ` Michal Hocko
2019-08-19 21:52         ` Joel Fernandes
2019-08-13 15:30   ` Joel Fernandes
2019-08-13 15:40     ` Jann Horn

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