Re: [PATCHv2] mm/page_owner: use kvmalloc instead of kmalloc
On Mon, Oct 29, 2018 at 10:16:43AM +0800, miles.c...@mediatek.com wrote: > The kbuf used by page owner is allocated by kmalloc(), which means it > can use only normal memory and there might be a "out of memory" > issue when we're out of normal memory. > > Use kvmalloc() so we can also allocate kbuf from > normal/hihghmem on 32bit kernel. That's a misconception: ret = kmalloc_node(size, kmalloc_flags, node); /* * It doesn't really make sense to fallback to vmalloc for sub page * requests */ if (ret || size <= PAGE_SIZE) return ret; Now, maybe this is an opportunity for us to improve kvmalloc. Maybe like this ... diff --git a/mm/util.c b/mm/util.c index 8bf08b5b5760..fdf5b34d2c28 100644 --- a/mm/util.c +++ b/mm/util.c @@ -416,10 +416,10 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node) ret = kmalloc_node(size, kmalloc_flags, node); /* -* It doesn't really make sense to fallback to vmalloc for sub page -* requests +* It only makes sense to fallback to vmalloc for sub page +* requests if we might be able to allocate highmem pages. */ - if (ret || size <= PAGE_SIZE) + if (ret || (!IS_ENABLED(CONFIG_HIGHMEM) && size <= PAGE_SIZE)) return ret; return __vmalloc_node_flags_caller(size, node, flags,
Re: [PATCHv2] mm/page_owner: use kvmalloc instead of kmalloc
On Mon, Oct 29, 2018 at 10:16:43AM +0800, miles.c...@mediatek.com wrote: > The kbuf used by page owner is allocated by kmalloc(), which means it > can use only normal memory and there might be a "out of memory" > issue when we're out of normal memory. > > Use kvmalloc() so we can also allocate kbuf from > normal/hihghmem on 32bit kernel. That's a misconception: ret = kmalloc_node(size, kmalloc_flags, node); /* * It doesn't really make sense to fallback to vmalloc for sub page * requests */ if (ret || size <= PAGE_SIZE) return ret; Now, maybe this is an opportunity for us to improve kvmalloc. Maybe like this ... diff --git a/mm/util.c b/mm/util.c index 8bf08b5b5760..fdf5b34d2c28 100644 --- a/mm/util.c +++ b/mm/util.c @@ -416,10 +416,10 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node) ret = kmalloc_node(size, kmalloc_flags, node); /* -* It doesn't really make sense to fallback to vmalloc for sub page -* requests +* It only makes sense to fallback to vmalloc for sub page +* requests if we might be able to allocate highmem pages. */ - if (ret || size <= PAGE_SIZE) + if (ret || (!IS_ENABLED(CONFIG_HIGHMEM) && size <= PAGE_SIZE)) return ret; return __vmalloc_node_flags_caller(size, node, flags,
[PATCHv2] mm/page_owner: use kvmalloc instead of kmalloc
From: Miles Chen The kbuf used by page owner is allocated by kmalloc(), which means it can use only normal memory and there might be a "out of memory" issue when we're out of normal memory. Use kvmalloc() so we can also allocate kbuf from normal/hihghmem on 32bit kernel. Clamp the kbuf size to PAGE_SIZE. Change since v1: - use kvmalloc() - clamp buffer size to PAGE_SIZE Signed-off-by: Miles Chen Cc: Joe Perches Cc: Matthew Wilcox Cc: Michal Hocko --- mm/page_owner.c | 8 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/mm/page_owner.c b/mm/page_owner.c index d80adfe..a064cd0 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -1,7 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 #include #include -#include #include #include #include @@ -351,7 +350,8 @@ void pagetypeinfo_showmixedcount_print(struct seq_file *m, .skip = 0 }; - kbuf = kmalloc(count, GFP_KERNEL); + count = count > PAGE_SIZE ? PAGE_SIZE : count; + kbuf = kvmalloc(count, GFP_KERNEL); if (!kbuf) return -ENOMEM; @@ -397,11 +397,11 @@ void pagetypeinfo_showmixedcount_print(struct seq_file *m, if (copy_to_user(buf, kbuf, ret)) ret = -EFAULT; - kfree(kbuf); + kvfree(kbuf); return ret; err: - kfree(kbuf); + kvfree(kbuf); return -ENOMEM; } -- 1.9.1
[PATCHv2] mm/page_owner: use kvmalloc instead of kmalloc
From: Miles Chen The kbuf used by page owner is allocated by kmalloc(), which means it can use only normal memory and there might be a "out of memory" issue when we're out of normal memory. Use kvmalloc() so we can also allocate kbuf from normal/hihghmem on 32bit kernel. Clamp the kbuf size to PAGE_SIZE. Change since v1: - use kvmalloc() - clamp buffer size to PAGE_SIZE Signed-off-by: Miles Chen Cc: Joe Perches Cc: Matthew Wilcox Cc: Michal Hocko --- mm/page_owner.c | 8 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/mm/page_owner.c b/mm/page_owner.c index d80adfe..a064cd0 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -1,7 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 #include #include -#include #include #include #include @@ -351,7 +350,8 @@ void pagetypeinfo_showmixedcount_print(struct seq_file *m, .skip = 0 }; - kbuf = kmalloc(count, GFP_KERNEL); + count = count > PAGE_SIZE ? PAGE_SIZE : count; + kbuf = kvmalloc(count, GFP_KERNEL); if (!kbuf) return -ENOMEM; @@ -397,11 +397,11 @@ void pagetypeinfo_showmixedcount_print(struct seq_file *m, if (copy_to_user(buf, kbuf, ret)) ret = -EFAULT; - kfree(kbuf); + kvfree(kbuf); return ret; err: - kfree(kbuf); + kvfree(kbuf); return -ENOMEM; } -- 1.9.1
