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Shutemov" To: Song Liu Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, oleg@redhat.com, rostedt@goodmis.org, mhiramat@kernel.org, matthew.wilcox@oracle.com, kirill.shutemov@linux.intel.com, kernel-team@fb.com Subject: Re: [PATCH v4 3/5] mm, thp: introduce FOLL_SPLIT_PMD Message-ID: <20190621124402.z4l67ck4vr5g7xe3@box> References: <20190613175747.1964753-1-songliubraving@fb.com> <20190613175747.1964753-4-songliubraving@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190613175747.1964753-4-songliubraving@fb.com> User-Agent: NeoMutt/20180716 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 Thu, Jun 13, 2019 at 10:57:45AM -0700, Song Liu wrote: > @@ -419,6 +419,11 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma, > put_page(page); > if (pmd_none(*pmd)) > return no_page_table(vma, flags); > + } else { /* flags & FOLL_SPLIT_PMD */ > + spin_unlock(ptl); > + ret = 0; > + split_huge_pmd(vma, pmd, address); > + pte_alloc(mm, pmd); pte_alloc() can fail and the failure should be propogated to the caller. -- Kirill A. Shutemov