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h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=BM48WV7hYmWiUmnDxQ3oRew/uliRrgx0D0KZyCHyPfwsttd7dkn2czRr/XktATdY2 DkRKudakyQe/pHVQAnqysUhYelbsKoNTuC+5yy+NCSgn85p6n6Y8rGFsA7/W9m97jd FOBKjpSZGGN10bSF/gAGt0+nT8zKt7skFxE/pgUI= Date: Tue, 22 Sep 2026 10:51:46 +0100 From: Catalin Marinas To: Breno Leitao Cc: Andrew Morton , 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: References: <20260921-b4-kmemleak-page-scan-v1-0-fb97d4801b3a@debian.org> <20260921-b4-kmemleak-page-scan-v1-2-fb97d4801b3a@debian.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260921-b4-kmemleak-page-scan-v1-2-fb97d4801b3a@debian.org> X-Rspam-User: X-Stat-Signature: 4g5e3fwezdwo3xfesk9f5dpse3mft6r5 X-Rspamd-Queue-Id: BDB1B140006 X-Rspamd-Server: rspam07 X-HE-Tag: 1790070710-628189 X-HE-Meta: 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 P9UwnESL 8JS4DxbYfVBEH9QkW7FQbmrs1l9FTie6XyBZ3RhCfZKd7hK5YQ6mu1JB1LFEJKP0uzm/dy8HsW+POPuyRWV1OOx3gHmWGxVQNjns+A46fioMP/bs7+AXdxlNuh+qwLMefXdgFmkJg6+sBfxN2EINygvEJOzuSgFHkvdNdr9ZHJmARKhxSIIO4aKK1uSVS9/EU2W1y7xqi2lQjbuUA5AXjRexdoOMdCFdNGDkljFCRStstg47fBsW87PcNIsgxFkhpYcplotBKPaE+vZdb3UeT59YYjigIfLBi5BR4N93y7qwR3ssEHbzaGCi/iZc+gjBMH5X1yQeNZI/qEX0= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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'. Also, MAX_SCAN_SIZE worth of bytes rather than words. Reviewed-by: Catalin Marinas