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Thu, 07 May 2020 00:42:39 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0470bmCE131715; Thu, 7 May 2020 00:42:38 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3030.oracle.com with ESMTP id 30t1r957v3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 07 May 2020 00:42:38 +0000 Received: from abhmp0014.oracle.com (abhmp0014.oracle.com [141.146.116.20]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 0470gZvx025355; Thu, 7 May 2020 00:42:35 GMT Received: from ayz-linux.localdomain (/68.7.158.207) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 06 May 2020 17:42:35 -0700 From: Anthony Yznaga To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: willy@infradead.org, corbet@lwn.net, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, rppt@linux.ibm.com, akpm@linux-foundation.org, hughd@google.com, ebiederm@xmission.com, masahiroy@kernel.org, ardb@kernel.org, ndesaulniers@google.com, dima@golovin.in, daniel.kiper@oracle.com, nivedita@alum.mit.edu, rafael.j.wysocki@intel.com, dan.j.williams@intel.com, zhenzhong.duan@oracle.com, jroedel@suse.de, bhe@redhat.com, guro@fb.com, Thomas.Lendacky@amd.com, andriy.shevchenko@linux.intel.com, keescook@chromium.org, hannes@cmpxchg.org, minchan@kernel.org, mhocko@kernel.org, ying.huang@intel.com, yang.shi@linux.alibaba.com, gustavo@embeddedor.com, ziqian.lzq@antfin.com, vdavydov.dev@gmail.com, jason.zeng@intel.com, kevin.tian@intel.com, zhiyuan.lv@intel.com, lei.l.li@intel.com, paul.c.lai@intel.com, ashok.raj@intel.com, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, kexec@lists.infradead.org Subject: [RFC 05/43] mm: PKRAM: support preserving transparent hugepages Date: Wed, 6 May 2020 17:41:31 -0700 Message-Id: <1588812129-8596-6-git-send-email-anthony.yznaga@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1588812129-8596-1-git-send-email-anthony.yznaga@oracle.com> References: <1588812129-8596-1-git-send-email-anthony.yznaga@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9613 signatures=668687 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 adultscore=0 suspectscore=2 spamscore=0 mlxlogscore=999 malwarescore=0 phishscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2005070001 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9613 signatures=668687 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 impostorscore=0 mlxscore=0 priorityscore=1501 lowpriorityscore=0 malwarescore=0 clxscore=1015 mlxlogscore=999 spamscore=0 adultscore=0 bulkscore=0 phishscore=0 suspectscore=2 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2005070001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Support preserving a transparent hugepage by recording the page order and a flag indicating it is a THP. Use these values when the page is restored to reconstruct the THP. Signed-off-by: Anthony Yznaga --- include/linux/pkram.h | 2 ++ mm/pkram.c | 20 ++++++++++++++++---- 2 files changed, 18 insertions(+), 4 deletions(-) diff --git a/include/linux/pkram.h b/include/linux/pkram.h index f338d1c2aeb6..584cadb662b4 100644 --- a/include/linux/pkram.h +++ b/include/linux/pkram.h @@ -33,6 +33,8 @@ int pkram_prepare_load_obj(struct pkram_stream *ps); void pkram_finish_load(struct pkram_stream *ps); void pkram_finish_load_obj(struct pkram_stream *ps); +#define PKRAM_PAGE_TRANS_HUGE 0x1 /* page is a transparent hugepage */ + int pkram_save_page(struct pkram_stream *ps, struct page *page, short flags); struct page *pkram_load_page(struct pkram_stream *ps, unsigned long *index, short *flags); diff --git a/mm/pkram.c b/mm/pkram.c index ab3053ca3539..9164060e36f5 100644 --- a/mm/pkram.c +++ b/mm/pkram.c @@ -21,6 +21,7 @@ typedef __u64 pkram_entry_t; #define PKRAM_ENTRY_FLAGS_SHIFT 0x5 #define PKRAM_ENTRY_FLAGS_MASK 0x7f +#define PKRAM_ENTRY_ORDER_MASK 0x1f /* * Keeps references to data pages saved to PKRAM. @@ -434,6 +435,7 @@ static int __pkram_save_page(struct pkram_stream *ps, struct pkram_link *link = ps->link; struct pkram_obj *obj = ps->obj; pkram_entry_t p; + int order; if (!link || ps->entry_idx >= PKRAM_LINK_ENTRIES_MAX || index != ps->next_index) { @@ -452,10 +454,15 @@ static int __pkram_save_page(struct pkram_stream *ps, ps->next_index = link->index = index; } - ps->next_index++; + if (PageTransHuge(page)) + flags |= PKRAM_PAGE_TRANS_HUGE; + + order = compound_order(page); + ps->next_index += (1 << order); get_page(page); p = page_to_phys(page); + p |= order; p |= ((flags & PKRAM_ENTRY_FLAGS_MASK) << PKRAM_ENTRY_FLAGS_SHIFT); link->entry[ps->entry_idx] = p; ps->entry_idx++; @@ -485,8 +492,6 @@ int pkram_save_page(struct pkram_stream *ps, struct page *page, short flags) BUG_ON((node->flags & PKRAM_ACCMODE_MASK) != PKRAM_SAVE); - BUG_ON(PageCompound(page)); - return __pkram_save_page(ps, page, flags, page->index); } @@ -499,6 +504,7 @@ static struct page *__pkram_load_page(struct pkram_stream *ps, unsigned long *in struct pkram_link *link = ps->link; struct page *page; pkram_entry_t p; + int order; short flgs; if (!link) { @@ -517,14 +523,20 @@ static struct page *__pkram_load_page(struct pkram_stream *ps, unsigned long *in BUG_ON(!p); flgs = (p >> PKRAM_ENTRY_FLAGS_SHIFT) & PKRAM_ENTRY_FLAGS_MASK; + order = p & PKRAM_ENTRY_ORDER_MASK; page = pfn_to_page(PHYS_PFN(p)); + if (flgs & PKRAM_PAGE_TRANS_HUGE) { + prep_compound_page(page, order); + prep_transhuge_page(page); + } + if (flags) *flags = flgs; if (index) *index = ps->next_index; - ps->next_index++; + ps->next_index += (1 << order); /* clear to avoid double free (see pkram_truncate_link()) */ link->entry[ps->entry_idx] = 0; -- 2.13.3