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Shutemov" X-Mailer: Apple Mail (2.3608.80.23.2.2) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9591 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 suspectscore=0 bulkscore=0 malwarescore=0 phishscore=0 adultscore=0 mlxscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004150019 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9591 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 adultscore=0 lowpriorityscore=0 impostorscore=0 malwarescore=0 bulkscore=0 priorityscore=1501 spamscore=0 suspectscore=0 mlxscore=0 mlxlogscore=999 clxscore=1011 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004150018 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Quick comments, mostly nits: [PATCH 5/6] khugepaged: Allow to collapse a page shared across fork > +static bool is_refcount_suitable(struct page *page) > +{ > + int expected_refcount, refcount; > + > + refcount = page_count(page); > + expected_refcount = total_mapcount(page); > + if (PageSwapCache(page)) > + expected_refcount += compound_nr(page); > + > + if (IS_ENABLED(CONFIG_DEBUG_VM) && expected_refcount > refcount) { > + pr_err("expected_refcount: %d, refcount: %d\n", > + expected_refcount, refcount); I'd rather see this message reworded slightly as I prefer to know WHY a value was unexpected directly from the error message: pr_err("expected_refcount (%d) > refcount (%d)\n", [PATCHv3, RESEND 7/8] thp: Change CoW semantics for anon-THP I really like the simplifications here. [PATCHv3, RESEND 8/8] khugepaged: Introduce 'max_ptes_shared' tunable As above, I'd like to see a tiny extra bit of specificity in the printf()s: +static void collapse_max_ptes_shared() +{ [ ... ] + if (check_huge(p)) + success("OK"); + else + fail("Fail"); + + printf("Trigger CoW in %d of %d...", printf("Trigger CoW on page %d of %d...", + hpage_pmd_nr - max_ptes_shared - 1, hpage_pmd_nr); + fill_memory(p, 0, (hpage_pmd_nr - max_ptes_shared - 1) * page_size); + if (!check_huge(p)) + success("OK"); + else + fail("Fail"); + + if (wait_for_scan("Do not collapse with max_ptes_shared exeeded", p)) + fail("Timeout"); + else if (!check_huge(p)) + success("OK"); + else + fail("Fail"); + + printf("Trigger CoW in %d of %d...", printf("Trigger CoW on page %d of %d...", + hpage_pmd_nr - max_ptes_shared, hpage_pmd_nr); + fill_memory(p, 0, (hpage_pmd_nr - max_ptes_shared) * page_size); + if (!check_huge(p)) + success("OK"); + else + fail("Fail"); Otherwise, for the khugepaged/THP series: Reviewed-by: William Kucharski