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From: Uladzislau Rezki <urezki@gmail.com>
To: Alice Ryhl <aliceryhl@google.com>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	shivamkalra98@zohomail.in,
	Shivam Kalra via B4 Relay
	<devnull+shivamkalra98.zohomail.in@kernel.org>,
	Uladzislau Rezki <urezki@gmail.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Danilo Krummrich <dakr@kernel.org>
Subject: Re: [PATCH v8 0/6] mm/vmalloc: free unused pages on vrealloc() shrink
Date: Mon, 30 Mar 2026 14:27:22 +0200	[thread overview]
Message-ID: <acpsKv-GmaYj2Bmx@milan> (raw)
In-Reply-To: <acou2CsZOUQPx5nW@google.com>

On Mon, Mar 30, 2026 at 08:05:44AM +0000, Alice Ryhl wrote:
> On Fri, Mar 27, 2026 at 11:37:58AM -0700, Andrew Morton wrote:
> > On Fri, 27 Mar 2026 15:18:36 +0530 Shivam Kalra via B4 Relay <devnull+shivamkalra98.zohomail.in@kernel.org> wrote:
> > 
> > > This series implements the TODO in vrealloc() to unmap and free unused
> > > pages when shrinking across a page boundary.
> > 
> > Thanks.  I'd prefer to defer this until the next -rc cycle
> > (https://lkml.kernel.org/r/20260323202941.08ddf2b0411501cae801ab4c@linux-foundation.org).
> > If Ulad would prefer that we push ahead then OK.
> 
> That's fine. No rush from my side.
> 
> > Are we able to describe how much memory this change might save under
> > various scenarios?  If the savings are impressively large then that
> > would get attention.
> 
> The primary purpose of this is to ensure that this scenario is not
> possible:
> 
> * There is a global list in the Binder driver. It's an array allocated
>   using kvmalloc and resized on demand using kvrealloc.
> * A process decides to add a bajillion elements to that global list.
> * The process exits, taking its entries with it.
> * The global list now remains extremely large for no good reason.
> 
> I don't know if it would save a significant amount of memory for
> well-behaved programs.
> 
> Alice
Agree, let's postpone this, so i have a chance to check it one more
time even though it seems ready.

--
Uladzislau Rezki


      reply	other threads:[~2026-03-30 12:27 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-27  9:48 [PATCH v8 0/6] mm/vmalloc: free unused pages on vrealloc() shrink Shivam Kalra via B4 Relay
2026-03-27  9:48 ` [PATCH v8 1/6] mm/vmalloc: extract vm_area_free_pages() helper from vfree() Shivam Kalra via B4 Relay
2026-03-27  9:48 ` [PATCH v8 2/6] mm/vmalloc: fix vrealloc() grow-in-place check Shivam Kalra via B4 Relay
2026-03-27  9:48 ` [PATCH v8 3/6] mm/vmalloc: zero newly exposed memory on vrealloc() grow Shivam Kalra via B4 Relay
2026-03-27  9:48 ` [PATCH v8 4/6] mm/vmalloc: use READ_ONCE() for vmalloc nr_pages status readers Shivam Kalra via B4 Relay
2026-03-27  9:48 ` [PATCH v8 5/6] mm/vmalloc: free unused pages on vrealloc() shrink Shivam Kalra via B4 Relay
2026-03-27  9:48 ` [PATCH v8 6/6] lib/test_vmalloc: add vrealloc test case Shivam Kalra via B4 Relay
2026-03-27 18:37 ` [PATCH v8 0/6] mm/vmalloc: free unused pages on vrealloc() shrink Andrew Morton
2026-03-27 19:31   ` Danilo Krummrich
2026-03-30  8:05   ` Alice Ryhl
2026-03-30 12:27     ` Uladzislau Rezki [this message]

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