From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from aserp2120.oracle.com ([141.146.126.78]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jWUf6-0002nx-BY for kexec@lists.infradead.org; Thu, 07 May 2020 00:45:27 +0000 From: Anthony Yznaga Subject: [RFC 03/43] mm: PKRAM: implement object load and save functions Date: Wed, 6 May 2020 17:41:29 -0700 Message-Id: <1588812129-8596-4-git-send-email-anthony.yznaga@oracle.com> In-Reply-To: <1588812129-8596-1-git-send-email-anthony.yznaga@oracle.com> References: <1588812129-8596-1-git-send-email-anthony.yznaga@oracle.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: x86@kernel.org, linux-doc@vger.kernel.org, gustavo@embeddedor.com, peterz@infradead.org, kexec@lists.infradead.org, paul.c.lai@intel.com, dave.hansen@linux.intel.com, mhocko@kernel.org, lei.l.li@intel.com, nivedita@alum.mit.edu, ziqian.lzq@antfin.com, hpa@zytor.com, ardb@kernel.org, ashok.raj@intel.com, bhe@redhat.com, corbet@lwn.net, masahiroy@kernel.org, rafael.j.wysocki@intel.com, hughd@google.com, willy@infradead.org, rppt@linux.ibm.com, mingo@redhat.com, vdavydov.dev@gmail.com, ying.huang@intel.com, Thomas.Lendacky@amd.com, kevin.tian@intel.com, jroedel@suse.de, keescook@chromium.org, dan.j.williams@intel.com, bp@alien8.de, zhiyuan.lv@intel.com, luto@kernel.org, tglx@linutronix.de, andriy.shevchenko@linux.intel.com, dima@golovin.in, yang.shi@linux.alibaba.com, ndesaulniers@google.com, zhenzhong.duan@oracle.com, guro@fb.com, minchan@kernel.org, ebiederm@xmission.com, jason.zeng@intel.com, hannes@cmpxchg.org, linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org, daniel.kiper@oracle.com PKRAM nodes are further divided into a list of objects. After a save operation has been initiated for a node, a save operation for an object associated with the node is initiated by calling pkram_prepare_save_obj(). A new object is created and linked to the node. The save operation for the object is committed by calling pkram_finish_save_obj(). After a load operation has been initiated, pkram_prepare_load_obj() is called to delete the next object from the node and prepare the corresponding stream for loading data from it. After the load of object has been finished, pkram_finish_load_obj() is called to free the object. Objects are also deleted when a save operation is discarded. Signed-off-by: Anthony Yznaga --- include/linux/pkram.h | 1 + mm/pkram.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 74 insertions(+), 4 deletions(-) diff --git a/include/linux/pkram.h b/include/linux/pkram.h index 83a0579e4c1c..fabde2cd8203 100644 --- a/include/linux/pkram.h +++ b/include/linux/pkram.h @@ -11,6 +11,7 @@ struct pkram_node; struct pkram_stream { gfp_t gfp_mask; struct pkram_node *node; + struct pkram_obj *obj; }; #define PKRAM_NAME_MAX 256 /* including nul */ diff --git a/mm/pkram.c b/mm/pkram.c index 5c57126353ff..4934ffd8b019 100644 --- a/mm/pkram.c +++ b/mm/pkram.c @@ -6,9 +6,14 @@ #include #include #include +#include #include #include +struct pkram_obj { + __u64 obj_pfn; /* points to the next object in the list */ +}; + /* * Preserved memory is divided into nodes that can be saved or loaded * independently of each other. The nodes are identified by unique name @@ -18,6 +23,7 @@ */ struct pkram_node { __u32 flags; + __u64 obj_pfn; /* points to the first obj of the node */ __u8 name[PKRAM_NAME_MAX]; }; @@ -62,6 +68,21 @@ static struct pkram_node *pkram_find_node(const char *name) return NULL; } +static void pkram_truncate_node(struct pkram_node *node) +{ + unsigned long obj_pfn; + struct pkram_obj *obj; + + obj_pfn = node->obj_pfn; + while (obj_pfn) { + obj = pfn_to_kaddr(obj_pfn); + obj_pfn = obj->obj_pfn; + pkram_free_page(obj); + cond_resched(); + } + node->obj_pfn = 0; +} + static void pkram_stream_init(struct pkram_stream *ps, struct pkram_node *node, gfp_t gfp_mask) { @@ -70,6 +91,11 @@ static void pkram_stream_init(struct pkram_stream *ps, ps->node = node; } +static void pkram_stream_init_obj(struct pkram_stream *ps, struct pkram_obj *obj) +{ + ps->obj = obj; +} + /** * Create a preserved memory node with name @name and initialize stream @ps * for saving data to it. @@ -124,12 +150,31 @@ int pkram_prepare_save(struct pkram_stream *ps, const char *name, gfp_t gfp_mask * * Returns 0 on success, -errno on failure. * + * Error values: + * %ENOMEM: insufficient memory available + * * After the save has finished, pkram_finish_save_obj() (or pkram_discard_save() * in case of failure) is to be called. */ int pkram_prepare_save_obj(struct pkram_stream *ps) { - return -ENOSYS; + struct pkram_node *node = ps->node; + struct pkram_obj *obj; + struct page *page; + + BUG_ON((node->flags & PKRAM_ACCMODE_MASK) != PKRAM_SAVE); + + page = pkram_alloc_page(GFP_KERNEL | __GFP_ZERO); + if (!page) + return -ENOMEM; + obj = page_address(page); + + if (node->obj_pfn) + obj->obj_pfn = node->obj_pfn; + node->obj_pfn = page_to_pfn(page); + + pkram_stream_init_obj(ps, obj); + return 0; } /** @@ -137,7 +182,9 @@ int pkram_prepare_save_obj(struct pkram_stream *ps) */ void pkram_finish_save_obj(struct pkram_stream *ps) { - BUG(); + struct pkram_node *node = ps->node; + + BUG_ON((node->flags & PKRAM_ACCMODE_MASK) != PKRAM_SAVE); } /** @@ -169,6 +216,7 @@ void pkram_discard_save(struct pkram_stream *ps) pkram_delete_node(node); mutex_unlock(&pkram_mutex); + pkram_truncate_node(node); pkram_free_page(node); } @@ -216,11 +264,26 @@ int pkram_prepare_load(struct pkram_stream *ps, const char *name) * * Returns 0 on success, -errno on failure. * + * Error values: + * %ENODATA: Stream @ps has no preserved memory objects + * * After the load has finished, pkram_finish_load_obj() is to be called. */ int pkram_prepare_load_obj(struct pkram_stream *ps) { - return -ENOSYS; + struct pkram_node *node = ps->node; + struct pkram_obj *obj; + + BUG_ON((node->flags & PKRAM_ACCMODE_MASK) != PKRAM_LOAD); + + if (!node->obj_pfn) + return -ENODATA; + + obj = pfn_to_kaddr(node->obj_pfn); + node->obj_pfn = obj->obj_pfn; + + pkram_stream_init_obj(ps, obj); + return 0; } /** @@ -230,7 +293,12 @@ int pkram_prepare_load_obj(struct pkram_stream *ps) */ void pkram_finish_load_obj(struct pkram_stream *ps) { - BUG(); + struct pkram_node *node = ps->node; + struct pkram_obj *obj = ps->obj; + + BUG_ON((node->flags & PKRAM_ACCMODE_MASK) != PKRAM_LOAD); + + pkram_free_page(obj); } /** @@ -244,6 +312,7 @@ void pkram_finish_load(struct pkram_stream *ps) BUG_ON((node->flags & PKRAM_ACCMODE_MASK) != PKRAM_LOAD); + pkram_truncate_node(node); pkram_free_page(node); } -- 2.13.3 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec