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Shutemov" To: Song Liu Cc: "linux-mm@kvack.org" , "linux-fsdevel@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "matthew.wilcox@oracle.com" , "kirill.shutemov@linux.intel.com" , Kernel Team , "william.kucharski@oracle.com" , "akpm@linux-foundation.org" , "hdanton@sina.com" Subject: Re: [PATCH v7 5/6] mm,thp: add read-only THP support for (non-shmem) FS Message-ID: <20190624142747.chy5s3nendxktm3l@box> References: <20190623054749.4016638-1-songliubraving@fb.com> <20190623054749.4016638-6-songliubraving@fb.com> <20190624124746.7evd2hmbn3qg3tfs@box> <52BDA50B-7CBF-4333-9D15-0C17FD04F6ED@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52BDA50B-7CBF-4333-9D15-0C17FD04F6ED@fb.com> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 24, 2019 at 02:01:05PM +0000, Song Liu wrote: > >> @@ -1392,6 +1403,23 @@ static void collapse_file(struct mm_struct *mm, > >> result = SCAN_FAIL; > >> goto xa_unlocked; > >> } > >> + } else if (!page || xa_is_value(page)) { > >> + xas_unlock_irq(&xas); > >> + page_cache_sync_readahead(mapping, &file->f_ra, file, > >> + index, PAGE_SIZE); > >> + lru_add_drain(); > > > > Why? > > isolate_lru_page() is likely to fail if we don't drain the pagevecs. Please add a comment. > >> + page = find_lock_page(mapping, index); > >> + if (unlikely(page == NULL)) { > >> + result = SCAN_FAIL; > >> + goto xa_unlocked; > >> + } > >> + } else if (!PageUptodate(page)) { > > > > Maybe we should try wait_on_page_locked() here before give up? > > Are you referring to the "if (!PageUptodate(page))" case? Yes. -- Kirill A. Shutemov