From: sashiko-bot@kernel.org
To: "Tarun Sahu" <tarunsahu@google.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
dmatlack@google.com, "Pasha Tatashin" <pasha.tatashin@soleen.com>,
"Mike Rapoport" <rppt@kernel.org>
Cc: kexec@lists.infradead.org, linux-mm@kvack.org,
"Pratyush Yadav" <pratyush@kernel.org>,
dev.jain@arm.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] memblock: use binary search to locate candidate regions
Date: Fri, 18 Sep 2026 00:28:45 +0000 [thread overview]
Message-ID: <20260918002846.3F13C1F000FF@smtp.kernel.org> (raw)
In-Reply-To: <20260918002239.4024231-2-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 worst-case complexity to O(N log N)
> (and O(N) for sequential appends), 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/20260918002239.4024231-1-tarunsahu@google.com?part=2
next prev parent reply other threads:[~2026-09-18 0:28 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-18 0:22 [PATCH v2 1/2] memblock: drop for_each_memblock_type() and open code its users Tarun Sahu
2026-09-18 0:22 ` [PATCH v2 2/2] memblock: use binary search to locate candidate regions Tarun Sahu
2026-09-18 0:28 ` sashiko-bot [this message]
2026-09-18 0:28 ` [PATCH v2 1/2] memblock: drop for_each_memblock_type() and open code its users sashiko-bot
2026-09-18 0:38 ` Pratyush Yadav
2026-09-26 9:30 ` tarunsahu
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