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([2620:10d:c092:500::5:89fc]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a68f2d64203sm367906666b.212.2024.06.04.05.42.26 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 04 Jun 2024 05:42:26 -0700 (PDT) Message-ID: <7253d276-1bbc-47a8-a5c3-c7c8ec43bab0@gmail.com> Date: Tue, 4 Jun 2024 13:42:25 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/2] mm: clear pte for folios that are zero filled To: Matthew Wilcox Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, yosryahmed@google.com, nphamcs@gmail.com, chengming.zhou@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com References: <20240604105950.1134192-1-usamaarif642@gmail.com> <20240604105950.1134192-2-usamaarif642@gmail.com> Content-Language: en-US From: Usama Arif In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 04/06/2024 13:18, Matthew Wilcox wrote: > On Tue, Jun 04, 2024 at 11:58:24AM +0100, Usama Arif wrote: >> +++ b/mm/rmap.c >> @@ -1819,96 +1819,101 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, >> */ >> dec_mm_counter(mm, mm_counter(folio)); >> } else if (folio_test_anon(folio)) { >> - swp_entry_t entry = page_swap_entry(subpage); >> - pte_t swp_pte; >> - /* >> - * Store the swap location in the pte. >> - * See handle_pte_fault() ... >> - */ >> - if (unlikely(folio_test_swapbacked(folio) != >> - folio_test_swapcache(folio))) { >> + if (flags & TTU_ZERO_FOLIO) { >> + pte_clear(mm, address, pvmw.pte); >> + dec_mm_counter(mm, MM_ANONPAGES); >> + } else { > This is very hard to review. Is what you've done the same as: > > if (flags & TTU_ZERO_FOLIO) { > pte_clear(mm, address, pvmw.pte); > dec_mm_counter(mm, MM_ANONPAGES); > goto discard; > } > > ? I genuinely can't tell. > Yes, thats what I am doing, will switch to above in next revision, Thanks!