From: sashiko-bot@kernel.org
To: "Andrew Morton" <akpm@linux-foundation.org>,
"Pratyush Yadav" <pratyush@kernel.org>,
"Mike Rapoport" <rppt@kernel.org>,
"Tarun Sahu" <tarunsahu@google.com>,
dmatlack@google.com, "Pasha Tatashin" <pasha.tatashin@soleen.com>
Cc: kexec@lists.infradead.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 2/2] memblock: use binary search to locate candidate regions
Date: Thu, 08 Oct 2026 19:14:50 +0000 [thread overview]
Message-ID: <sashiko-outbox-164506@kernel.org> (raw)
In-Reply-To: <20261008190828.3221718-2-tarunsahu@google.com>
> Use binary search (memblock_bsearch_start) in memblock_add_range() and
> memblock_isolate_range() to locate candidate regions instead of linearly
> scanning from index 0.
>
> Under heavy memory fragmentation (such as KHO page preservation registering
> hundreds of thousands of disjoint folios), scanning from index 0 on every
> insertion and isolation results in O(N^2) complexity, causing boot-time
> memory retrieval to take several minutes (~268s for 393k pages).
>
> Using binary search reduces the candidate search complexity to O(log N)
> (from O(N)), cutting KHO memory retrieval time from ~268s to ~50ms.
>
> memblock_search() open codes the same binary search, so reimplement it on
> top of the new helper.
>
> Signed-off-by: Tarun Sahu <tarunsahu@google.com>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261008190828.3221718-1-tarunsahu@google.com?part=2
next prev parent reply other threads:[~2026-10-08 19:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-08 19:08 [PATCH v4 1/2] memblock: drop for_each_memblock_type() and open code its users Tarun Sahu
2026-10-08 19:08 ` [PATCH v4 2/2] memblock: use binary search to locate candidate regions Tarun Sahu
2026-10-08 19:14 ` sashiko-bot [this message]
2026-10-09 17:00 ` Mike Rapoport
2026-10-08 19:12 ` [PATCH v4 1/2] memblock: drop for_each_memblock_type() and open code its users sashiko-bot
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