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Groups > linux.kernel > #1626043
| From | Matthew Wilcox <willy@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") |
| Date | 2017-04-19 14:00 +0200 |
| Message-ID | <txWr7-30n-1@gated-at.bofh.it> (permalink) |
| References | <tx3XH-2FQ-9@gated-at.bofh.it> <txgLg-2iD-21@gated-at.bofh.it> <txoSt-7uv-1@gated-at.bofh.it> <txvTY-3om-15@gated-at.bofh.it> <txQYp-8cc-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Wed, Apr 19, 2017 at 03:02:37PM +0900, Minchan Kim wrote: > On Tue, Apr 18, 2017 at 09:33:07AM +0200, Michal Hocko wrote: > > I do not follow. Why would you need kmap for something that is already > > in the kernel space? > > Because it can work with highmem pages. That's copy_user_highpage(). If you want to define a new arch API copy_highpage(), feel free to make a case for it ... > > > Another approach is the API does normal thing for non-aligned prefix and > > > tail space and fast thing for aligned space. > > > Otherwise, it would be happy if the API has WARN_ON non-page SIZE aligned > > > address. Why not just use memcpy()? Is copy_page() significantly faster than memcpy() for a PAGE_SIZE amount of data?
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copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-04-17 03:50 +0200
Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") Christoph Lameter <cl@linux.com> - 2017-04-17 17:30 +0200
Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") Minchan Kim <minchan@kernel.org> - 2017-04-18 02:10 +0200
Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") Michal Hocko <mhocko@kernel.org> - 2017-04-18 09:40 +0200
Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") Michal Hocko <mhocko@kernel.org> - 2017-04-18 13:10 +0200
Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-04-19 08:20 +0200
Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-04-18 13:10 +0200
Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") Minchan Kim <minchan@kernel.org> - 2017-04-19 08:10 +0200
Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") Matthew Wilcox <willy@infradead.org> - 2017-04-19 14:00 +0200
Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-04-20 03:50 +0200
Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") Minchan Kim <minchan@kernel.org> - 2017-04-20 09:00 +0200
Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-04-18 12:50 +0200
Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") Christoph Lameter <cl@linux.com> - 2017-04-18 15:30 +0200
Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") Matthew Wilcox <willy@infradead.org> - 2017-04-18 15:20 +0200
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