Re: [PATCH RFC PKS/PMEM 33/58] fs/cramfs: Utilize new kmap_thread()
On Tue, Oct 13, 2020 at 09:01:49PM +0100, Al Viro wrote:
> On Tue, Oct 13, 2020 at 08:36:43PM +0100, Matthew Wilcox wrote:
>
> > static inline void copy_to_highpage(struct page *to, void *vfrom, unsigned
> > int size)
> > {
> > char *vto = kmap_atomic(to);
> >
> > memcpy(vto, vfrom, size);
> > kunmap_atomic(vto);
> > }
> >
> > in linux/highmem.h ?
>
> You mean, like
> static void memcpy_from_page(char *to, struct page *page, size_t offset,
> size_t len)
> {
> char *from = kmap_atomic(page);
> memcpy(to, from + offset, len);
> kunmap_atomic(from);
> }
>
> static void memcpy_to_page(struct page *page, size_t offset, const char
> *from, size_t len)
> {
> char *to = kmap_atomic(page);
> memcpy(to + offset, from, len);
> kunmap_atomic(to);
> }
>
> static void memzero_page(struct page *page, size_t offset, size_t len)
> {
> char *addr = kmap_atomic(page);
> memset(addr + offset, 0, len);
> kunmap_atomic(addr);
> }
>
> in lib/iov_iter.c? FWIW, I don't like that "highpage" in the name and
> highmem.h as location - these make perfect sense regardless of highmem;
> they are normal memory operations with page + offset used instead of
> a pointer...
I was thinking along those lines as well especially because of the direction
this patch set takes kmap().
Thanks for pointing these out to me. How about I lift them to a common header?
But if not highmem.h where?
Ira
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Re: [PATCH RFC PKS/PMEM 33/58] fs/cramfs: Utilize new kmap_thread()
On Tue, Oct 13, 2020 at 08:36:43PM +0100, Matthew Wilcox wrote:
> On Tue, Oct 13, 2020 at 11:44:29AM -0700, Dan Williams wrote:
> > On Fri, Oct 9, 2020 at 12:52 PM wrote:
> > >
> > > From: Ira Weiny
> > >
> > > The kmap() calls in this FS are localized to a single thread. To avoid
> > > the over head of global PKRS updates use the new kmap_thread() call.
> > >
> > > Cc: Nicolas Pitre
> > > Signed-off-by: Ira Weiny
> > > ---
> > > fs/cramfs/inode.c | 10 +-
> > > 1 file changed, 5 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
> > > index 912308600d39..003c014a42ed 100644
> > > --- a/fs/cramfs/inode.c
> > > +++ b/fs/cramfs/inode.c
> > > @@ -247,8 +247,8 @@ static void *cramfs_blkdev_read(struct super_block
> > > *sb, unsigned int offset,
> > > struct page *page = pages[i];
> > >
> > > if (page) {
> > > - memcpy(data, kmap(page), PAGE_SIZE);
> > > - kunmap(page);
> > > + memcpy(data, kmap_thread(page), PAGE_SIZE);
> > > + kunmap_thread(page);
> >
> > Why does this need a sleepable kmap? This looks like a textbook
> > kmap_atomic() use case.
>
> There's a lot of code of this form. Could we perhaps have:
>
> static inline void copy_to_highpage(struct page *to, void *vfrom, unsigned
> int size)
> {
> char *vto = kmap_atomic(to);
>
> memcpy(vto, vfrom, size);
> kunmap_atomic(vto);
> }
>
> in linux/highmem.h ?
Christoph had the same idea. I'll work on it.
Ira
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Re: [PATCH RFC PKS/PMEM 33/58] fs/cramfs: Utilize new kmap_thread()
On Tue, Oct 13, 2020 at 08:36:43PM +0100, Matthew Wilcox wrote:
> static inline void copy_to_highpage(struct page *to, void *vfrom, unsigned
> int size)
> {
> char *vto = kmap_atomic(to);
>
> memcpy(vto, vfrom, size);
> kunmap_atomic(vto);
> }
>
> in linux/highmem.h ?
You mean, like
static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t
len)
{
char *from = kmap_atomic(page);
memcpy(to, from + offset, len);
kunmap_atomic(from);
}
static void memcpy_to_page(struct page *page, size_t offset, const char *from,
size_t len)
{
char *to = kmap_atomic(page);
memcpy(to + offset, from, len);
kunmap_atomic(to);
}
static void memzero_page(struct page *page, size_t offset, size_t len)
{
char *addr = kmap_atomic(page);
memset(addr + offset, 0, len);
kunmap_atomic(addr);
}
in lib/iov_iter.c? FWIW, I don't like that "highpage" in the name and
highmem.h as location - these make perfect sense regardless of highmem;
they are normal memory operations with page + offset used instead of
a pointer...
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Re: [PATCH RFC PKS/PMEM 33/58] fs/cramfs: Utilize new kmap_thread()
On Tue, Oct 13, 2020 at 12:37 PM Matthew Wilcox wrote:
>
> On Tue, Oct 13, 2020 at 11:44:29AM -0700, Dan Williams wrote:
> > On Fri, Oct 9, 2020 at 12:52 PM wrote:
> > >
> > > From: Ira Weiny
> > >
> > > The kmap() calls in this FS are localized to a single thread. To avoid
> > > the over head of global PKRS updates use the new kmap_thread() call.
> > >
> > > Cc: Nicolas Pitre
> > > Signed-off-by: Ira Weiny
> > > ---
> > > fs/cramfs/inode.c | 10 +-
> > > 1 file changed, 5 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
> > > index 912308600d39..003c014a42ed 100644
> > > --- a/fs/cramfs/inode.c
> > > +++ b/fs/cramfs/inode.c
> > > @@ -247,8 +247,8 @@ static void *cramfs_blkdev_read(struct super_block
> > > *sb, unsigned int offset,
> > > struct page *page = pages[i];
> > >
> > > if (page) {
> > > - memcpy(data, kmap(page), PAGE_SIZE);
> > > - kunmap(page);
> > > + memcpy(data, kmap_thread(page), PAGE_SIZE);
> > > + kunmap_thread(page);
> >
> > Why does this need a sleepable kmap? This looks like a textbook
> > kmap_atomic() use case.
>
> There's a lot of code of this form. Could we perhaps have:
>
> static inline void copy_to_highpage(struct page *to, void *vfrom, unsigned
> int size)
> {
> char *vto = kmap_atomic(to);
>
> memcpy(vto, vfrom, size);
> kunmap_atomic(vto);
> }
>
> in linux/highmem.h ?
Nice, yes, that could also replace the local ones in lib/iov_iter.c
(memcpy_{to,from}_page())
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Re: [PATCH RFC PKS/PMEM 33/58] fs/cramfs: Utilize new kmap_thread()
On Tue, Oct 13, 2020 at 11:44:29AM -0700, Dan Williams wrote:
> On Fri, Oct 9, 2020 at 12:52 PM wrote:
> >
> > From: Ira Weiny
> >
> > The kmap() calls in this FS are localized to a single thread. To avoid
> > the over head of global PKRS updates use the new kmap_thread() call.
> >
> > Cc: Nicolas Pitre
> > Signed-off-by: Ira Weiny
> > ---
> > fs/cramfs/inode.c | 10 +-
> > 1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
> > index 912308600d39..003c014a42ed 100644
> > --- a/fs/cramfs/inode.c
> > +++ b/fs/cramfs/inode.c
> > @@ -247,8 +247,8 @@ static void *cramfs_blkdev_read(struct super_block *sb,
> > unsigned int offset,
> > struct page *page = pages[i];
> >
> > if (page) {
> > - memcpy(data, kmap(page), PAGE_SIZE);
> > - kunmap(page);
> > + memcpy(data, kmap_thread(page), PAGE_SIZE);
> > + kunmap_thread(page);
>
> Why does this need a sleepable kmap? This looks like a textbook
> kmap_atomic() use case.
There's a lot of code of this form. Could we perhaps have:
static inline void copy_to_highpage(struct page *to, void *vfrom, unsigned int
size)
{
char *vto = kmap_atomic(to);
memcpy(vto, vfrom, size);
kunmap_atomic(vto);
}
in linux/highmem.h ?
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Re: [PATCH RFC PKS/PMEM 33/58] fs/cramfs: Utilize new kmap_thread()
On Fri, Oct 9, 2020 at 12:52 PM wrote:
>
> From: Ira Weiny
>
> The kmap() calls in this FS are localized to a single thread. To avoid
> the over head of global PKRS updates use the new kmap_thread() call.
>
> Cc: Nicolas Pitre
> Signed-off-by: Ira Weiny
> ---
> fs/cramfs/inode.c | 10 +-
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
> index 912308600d39..003c014a42ed 100644
> --- a/fs/cramfs/inode.c
> +++ b/fs/cramfs/inode.c
> @@ -247,8 +247,8 @@ static void *cramfs_blkdev_read(struct super_block *sb,
> unsigned int offset,
> struct page *page = pages[i];
>
> if (page) {
> - memcpy(data, kmap(page), PAGE_SIZE);
> - kunmap(page);
> + memcpy(data, kmap_thread(page), PAGE_SIZE);
> + kunmap_thread(page);
Why does this need a sleepable kmap? This looks like a textbook
kmap_atomic() use case.
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Re: [PATCH RFC PKS/PMEM 33/58] fs/cramfs: Utilize new kmap_thread()
On Fri, 9 Oct 2020, ira.we...@intel.com wrote:
> From: Ira Weiny
>
> The kmap() calls in this FS are localized to a single thread. To avoid
> the over head of global PKRS updates use the new kmap_thread() call.
>
> Cc: Nicolas Pitre
> Signed-off-by: Ira Weiny
Acked-by: Nicolas Pitre
> fs/cramfs/inode.c | 10 +-
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
> index 912308600d39..003c014a42ed 100644
> --- a/fs/cramfs/inode.c
> +++ b/fs/cramfs/inode.c
> @@ -247,8 +247,8 @@ static void *cramfs_blkdev_read(struct super_block *sb,
> unsigned int offset,
> struct page *page = pages[i];
>
> if (page) {
> - memcpy(data, kmap(page), PAGE_SIZE);
> - kunmap(page);
> + memcpy(data, kmap_thread(page), PAGE_SIZE);
> + kunmap_thread(page);
> put_page(page);
> } else
> memset(data, 0, PAGE_SIZE);
> @@ -826,7 +826,7 @@ static int cramfs_readpage(struct file *file, struct page
> *page)
>
> maxblock = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
> bytes_filled = 0;
> - pgdata = kmap(page);
> + pgdata = kmap_thread(page);
>
> if (page->index < maxblock) {
> struct super_block *sb = inode->i_sb;
> @@ -914,13 +914,13 @@ static int cramfs_readpage(struct file *file, struct
> page *page)
>
> memset(pgdata + bytes_filled, 0, PAGE_SIZE - bytes_filled);
> flush_dcache_page(page);
> - kunmap(page);
> + kunmap_thread(page);
> SetPageUptodate(page);
> unlock_page(page);
> return 0;
>
> err:
> - kunmap(page);
> + kunmap_thread(page);
> ClearPageUptodate(page);
> SetPageError(page);
> unlock_page(page);
> --
> 2.28.0.rc0.12.gb6a658bd00c9
>
>
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[PATCH RFC PKS/PMEM 33/58] fs/cramfs: Utilize new kmap_thread()
From: Ira Weiny
The kmap() calls in this FS are localized to a single thread. To avoid
the over head of global PKRS updates use the new kmap_thread() call.
Cc: Nicolas Pitre
Signed-off-by: Ira Weiny
---
fs/cramfs/inode.c | 10 +-
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
index 912308600d39..003c014a42ed 100644
--- a/fs/cramfs/inode.c
+++ b/fs/cramfs/inode.c
@@ -247,8 +247,8 @@ static void *cramfs_blkdev_read(struct super_block *sb,
unsigned int offset,
struct page *page = pages[i];
if (page) {
- memcpy(data, kmap(page), PAGE_SIZE);
- kunmap(page);
+ memcpy(data, kmap_thread(page), PAGE_SIZE);
+ kunmap_thread(page);
put_page(page);
} else
memset(data, 0, PAGE_SIZE);
@@ -826,7 +826,7 @@ static int cramfs_readpage(struct file *file, struct page
*page)
maxblock = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
bytes_filled = 0;
- pgdata = kmap(page);
+ pgdata = kmap_thread(page);
if (page->index < maxblock) {
struct super_block *sb = inode->i_sb;
@@ -914,13 +914,13 @@ static int cramfs_readpage(struct file *file, struct page
*page)
memset(pgdata + bytes_filled, 0, PAGE_SIZE - bytes_filled);
flush_dcache_page(page);
- kunmap(page);
+ kunmap_thread(page);
SetPageUptodate(page);
unlock_page(page);
return 0;
err:
- kunmap(page);
+ kunmap_thread(page);
ClearPageUptodate(page);
SetPageError(page);
unlock_page(page);
--
2.28.0.rc0.12.gb6a658bd00c9
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