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Shutemov" To: "Matthew Wilcox (Oracle)" Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 02/12] filemap: Use folio_put_refs() in filemap_free_folio() Message-ID: <20220117155641.u5ysambg72nq2p6y@box.shutemov.name> References: <20220116121822.1727633-1-willy@infradead.org> <20220116121822.1727633-3-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220116121822.1727633-3-willy@infradead.org> X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: A7B3A140004 X-Stat-Signature: 78oixpp46hykomhaqy77qz7b7kdnbn4e Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=shutemov-name.20210112.gappssmtp.com header.s=20210112 header.b=vWlPwu36; spf=none (imf26.hostedemail.com: domain of kirill@shutemov.name has no SPF policy when checking 209.85.167.53) smtp.mailfrom=kirill@shutemov.name; dmarc=none X-HE-Tag: 1642434975-281083 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sun, Jan 16, 2022 at 12:18:12PM +0000, Matthew Wilcox (Oracle) wrote: > This shrinks filemap_free_folio() by 55 bytes in my .config; 24 bytes > from removing the VM_BUG_ON_FOLIO() and 31 bytes from unifying the > small/large folio paths. > > We could just use folio_ref_sub() here since the caller should hold a > reference (as the VM_BUG_ON_FOLIO() was asserting), but that's fragile. > > Signed-off-by: Matthew Wilcox (Oracle) > --- > mm/filemap.c | 10 ++++------ > 1 file changed, 4 insertions(+), 6 deletions(-) > > diff --git a/mm/filemap.c b/mm/filemap.c > index 2fd9b2f24025..afc8f5ca85ac 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -231,17 +231,15 @@ void __filemap_remove_folio(struct folio *folio, void *shadow) > void filemap_free_folio(struct address_space *mapping, struct folio *folio) > { > void (*freepage)(struct page *); > + int refs = 1; > > freepage = mapping->a_ops->freepage; > if (freepage) > freepage(&folio->page); > > - if (folio_test_large(folio) && !folio_test_hugetlb(folio)) { > - folio_ref_sub(folio, folio_nr_pages(folio)); > - VM_BUG_ON_FOLIO(folio_ref_count(folio) <= 0, folio); > - } else { > - folio_put(folio); > - } > + if (folio_test_large(folio) && !folio_test_hugetlb(folio)) > + refs = folio_nr_pages(folio); Isn't folio_test_large() check redundant? folio_nr_pages() would return 1 for non-large folio, wouldn't it? > + folio_put_refs(folio, refs); > } > > /** > -- > 2.34.1 > -- Kirill A. Shutemov