From: Anthony Yznaga <anthony.yznaga@oracle.com> To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: 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@kernel.org, akpm@linux-foundation.org, ebiederm@xmission.com, keescook@chromium.org, graf@amazon.com, jason.zeng@intel.com, lei.l.li@intel.com, steven.sistare@oracle.com, fam.zheng@bytedance.com, mgalaxy@akamai.com, kexec@lists.infradead.org Subject: [RFC v3 18/21] mm: PKRAM: allow preserved memory to be freed from userspace Date: Wed, 26 Apr 2023 17:08:54 -0700 [thread overview] Message-ID: <1682554137-13938-19-git-send-email-anthony.yznaga@oracle.com> (raw) In-Reply-To: <1682554137-13938-1-git-send-email-anthony.yznaga@oracle.com> To free all space utilized for preserved memory, one can write 0 to /sys/kernel/pkram. This will destroy all PKRAM nodes that are not currently being read or written. Originally-by: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com> --- mm/pkram.c | 39 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 38 insertions(+), 1 deletion(-) diff --git a/mm/pkram.c b/mm/pkram.c index 474fb6fc8355..d404e415f3cb 100644 --- a/mm/pkram.c +++ b/mm/pkram.c @@ -493,6 +493,32 @@ static void pkram_truncate_node(struct pkram_node *node) node->obj_pfn = 0; } +/* + * Free all nodes that are not under operation. + */ +static void pkram_truncate(void) +{ + struct page *page, *tmp; + struct pkram_node *node; + LIST_HEAD(dispose); + + mutex_lock(&pkram_mutex); + list_for_each_entry_safe(page, tmp, &pkram_nodes, lru) { + node = page_address(page); + if (!(node->flags & PKRAM_ACCMODE_MASK)) + list_move(&page->lru, &dispose); + } + mutex_unlock(&pkram_mutex); + + while (!list_empty(&dispose)) { + page = list_first_entry(&dispose, struct page, lru); + list_del(&page->lru); + node = page_address(page); + pkram_truncate_node(node); + pkram_free_page(node); + } +} + static void pkram_add_link(struct pkram_link *link, struct pkram_data_stream *pds) { __u64 link_pfn = page_to_pfn(virt_to_page(link)); @@ -1252,8 +1278,19 @@ static ssize_t show_pkram_sb_pfn(struct kobject *kobj, return sprintf(buf, "%lx\n", pfn); } +static ssize_t store_pkram_sb_pfn(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, size_t count) +{ + int val; + + if (kstrtoint(buf, 0, &val) || val) + return -EINVAL; + pkram_truncate(); + return count; +} + static struct kobj_attribute pkram_sb_pfn_attr = - __ATTR(pkram, 0444, show_pkram_sb_pfn, NULL); + __ATTR(pkram, 0644, show_pkram_sb_pfn, store_pkram_sb_pfn); static struct attribute *pkram_attrs[] = { &pkram_sb_pfn_attr.attr, -- 1.9.4 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
WARNING: multiple messages have this Message-ID (diff)
From: Anthony Yznaga <anthony.yznaga@oracle.com> To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: 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@kernel.org, akpm@linux-foundation.org, ebiederm@xmission.com, keescook@chromium.org, graf@amazon.com, jason.zeng@intel.com, lei.l.li@intel.com, steven.sistare@oracle.com, fam.zheng@bytedance.com, mgalaxy@akamai.com, kexec@lists.infradead.org Subject: [RFC v3 18/21] mm: PKRAM: allow preserved memory to be freed from userspace Date: Wed, 26 Apr 2023 17:08:54 -0700 [thread overview] Message-ID: <1682554137-13938-19-git-send-email-anthony.yznaga@oracle.com> (raw) In-Reply-To: <1682554137-13938-1-git-send-email-anthony.yznaga@oracle.com> To free all space utilized for preserved memory, one can write 0 to /sys/kernel/pkram. This will destroy all PKRAM nodes that are not currently being read or written. Originally-by: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com> --- mm/pkram.c | 39 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 38 insertions(+), 1 deletion(-) diff --git a/mm/pkram.c b/mm/pkram.c index 474fb6fc8355..d404e415f3cb 100644 --- a/mm/pkram.c +++ b/mm/pkram.c @@ -493,6 +493,32 @@ static void pkram_truncate_node(struct pkram_node *node) node->obj_pfn = 0; } +/* + * Free all nodes that are not under operation. + */ +static void pkram_truncate(void) +{ + struct page *page, *tmp; + struct pkram_node *node; + LIST_HEAD(dispose); + + mutex_lock(&pkram_mutex); + list_for_each_entry_safe(page, tmp, &pkram_nodes, lru) { + node = page_address(page); + if (!(node->flags & PKRAM_ACCMODE_MASK)) + list_move(&page->lru, &dispose); + } + mutex_unlock(&pkram_mutex); + + while (!list_empty(&dispose)) { + page = list_first_entry(&dispose, struct page, lru); + list_del(&page->lru); + node = page_address(page); + pkram_truncate_node(node); + pkram_free_page(node); + } +} + static void pkram_add_link(struct pkram_link *link, struct pkram_data_stream *pds) { __u64 link_pfn = page_to_pfn(virt_to_page(link)); @@ -1252,8 +1278,19 @@ static ssize_t show_pkram_sb_pfn(struct kobject *kobj, return sprintf(buf, "%lx\n", pfn); } +static ssize_t store_pkram_sb_pfn(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, size_t count) +{ + int val; + + if (kstrtoint(buf, 0, &val) || val) + return -EINVAL; + pkram_truncate(); + return count; +} + static struct kobj_attribute pkram_sb_pfn_attr = - __ATTR(pkram, 0444, show_pkram_sb_pfn, NULL); + __ATTR(pkram, 0644, show_pkram_sb_pfn, store_pkram_sb_pfn); static struct attribute *pkram_attrs[] = { &pkram_sb_pfn_attr.attr, -- 1.9.4
next prev parent reply other threads:[~2023-04-27 0:10 UTC|newest] Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-04-27 0:08 [RFC v3 00/21] Preserved-over-Kexec RAM Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 01/21] mm: add PKRAM API stubs and Kconfig Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 02/21] mm: PKRAM: implement node load and save functions Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 03/21] mm: PKRAM: implement object " Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 04/21] mm: PKRAM: implement folio stream operations Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 05/21] mm: PKRAM: implement byte " Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 06/21] mm: PKRAM: link nodes by pfn before reboot Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 07/21] mm: PKRAM: introduce super block Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-06-05 2:40 ` Coiby Xu 2023-06-05 2:40 ` Coiby Xu 2023-06-06 2:01 ` Anthony Yznaga 2023-06-06 2:01 ` Anthony Yznaga 2023-06-06 2:55 ` Coiby Xu 2023-06-06 2:55 ` Coiby Xu 2023-06-06 3:12 ` Anthony Yznaga 2023-06-06 3:12 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 08/21] PKRAM: track preserved pages in a physical mapping pagetable Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 09/21] PKRAM: pass a list of preserved ranges to the next kernel Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 10/21] PKRAM: prepare for adding preserved ranges to memblock reserved Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 11/21] mm: PKRAM: reserve preserved memory at boot Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 12/21] PKRAM: free the preserved ranges list Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 13/21] PKRAM: prevent inadvertent use of a stale superblock Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 14/21] PKRAM: provide a way to ban pages from use by PKRAM Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 15/21] kexec: PKRAM: prevent kexec clobbering preserved pages in some cases Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 16/21] PKRAM: provide a way to check if a memory range has preserved pages Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 17/21] kexec: PKRAM: avoid clobbering already " Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga [this message] 2023-04-27 0:08 ` [RFC v3 18/21] mm: PKRAM: allow preserved memory to be freed from userspace Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 19/21] PKRAM: disable feature when running the kdump kernel Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 20/21] x86/KASLR: PKRAM: support physical kaslr Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 0:08 ` [RFC v3 21/21] x86/boot/compressed/64: use 1GB pages for mappings Anthony Yznaga 2023-04-27 0:08 ` Anthony Yznaga 2023-04-27 18:40 ` H. Peter Anvin 2023-04-27 18:40 ` H. Peter Anvin 2023-04-27 22:38 ` Anthony Yznaga 2023-04-27 22:38 ` Anthony Yznaga 2023-05-26 13:57 ` [RFC v3 00/21] Preserved-over-Kexec RAM Gowans, James 2023-05-26 13:57 ` Gowans, James 2023-05-31 23:14 ` Anthony Yznaga 2023-05-31 23:14 ` Anthony Yznaga 2023-06-01 2:15 ` Baoquan He 2023-06-01 2:15 ` Baoquan He 2023-06-01 23:58 ` Anthony Yznaga 2023-06-01 23:58 ` Anthony Yznaga
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