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Date: Tue, 22 Sep 2026 18:39:21 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Breno Leitao <leitao@debian.org>, linux-mm@kvack.org,
 linux-kernel@vger.kernel.org, kernel-team@meta.com
Subject: Re: [PATCH 2/2] mm: kmemleak: scan the struct page array in
 MAX_SCAN_SIZE batches
Message-Id: <20260922183921.b30bc1c3ba9443e021910851@linux-foundation.org>
In-Reply-To: <arJPsqUSHGiitXQR@arm.com>
References: <20260921-b4-kmemleak-page-scan-v1-0-fb97d4801b3a@debian.org>
	<20260921-b4-kmemleak-page-scan-v1-2-fb97d4801b3a@debian.org>
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On Tue, 22 Sep 2026 10:51:46 +0100 Catalin Marinas <catalin.marinas@arm.com> wrote:

> On Mon, Sep 21, 2026 at 05:30:27AM -0700, Breno Leitao wrote:
> > scan_zone_pages() scans the struct page array one page per scan_block()
> > call:
> > 
> > 	if (scan_block(page, page + 1, NULL))
> > 
> > scan_block() takes kmemleak_lock with interrupts disabled for the
> > duration of the call, so this acquires the lock once per online PFN to
> > scan a single struct page.
> > 
> > Gather runs of adjacent eligible struct pages and pass each run to
> > scan_block() in one call, capped at MAX_SCAN_SIZE.
> > 
> > The longest kmemleak_lock is now held is MAX_SCAN_SIZE worth of words,
> 
> Remove an 'is'.

That was actually correct, but it doesn't read well.

> Also, MAX_SCAN_SIZE worth of bytes rather than words.

edited, thanks.

How's this?

: The longest kmemleak_lock hold duration is now MAX_SCAN_SIZE worth of
: bytes.  The same bound scan_large_block() already applies to the data
: sections and the per-CPU areas.