From: Alice Ryhl <aliceryhl@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: 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 08:05:44 +0000 [thread overview]
Message-ID: <acou2CsZOUQPx5nW@google.com> (raw)
In-Reply-To: <20260327113758.75f04588310a707b4d4b1aac@linux-foundation.org>
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
next prev parent reply other threads:[~2026-03-30 8:05 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 [this message]
2026-03-30 12:27 ` Uladzislau Rezki
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