On Mon, 24 Jan 2011 14:55:58 -0800 Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote: > From: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx> > > I'm proposing this series for 2.6.39. > > We've had apply_to_page_range() for a while, which is a general way to > apply a function to ptes across a range of addresses - including > allocating any missing parts of the pagetable as needed. This logic > is replicated in a number of places throughout the kernel, but it > hasn't been widely replaced by this function, partly because of > concerns about the overhead of calling the function once per pte. > > This series adds apply_to_page_range_batch() (and reimplements > apply_to_page_range() in terms of it), which calls the pte operation > function once per pte page, moving the inner loop into the callback > function. > > apply_to_page_range(_batch) also calls its callback with lazy mmu > updates enabled, which allows batching of the operations in > environments where this is beneficial (ie, virtualization). The only > caveat this introduces is callbacks can't expect to immediately see > the effects of the pte updates in memory. > > Since this is effectively identical to the code in lib/ioremap.c and > mm/vmalloc.c (twice!), I replace their open-coded variants. I'm sure > there are others places in the kernel which could do with this (I only > stumbled over ioremap by accident). > > I also add a minor optimisation to vunmap_page_range() to use a > plain pte_clear() rather than the more expensive and unnecessary > ptep_get_and_clear(). > > Jeremy Fitzhardinge (9): > mm: remove unused "token" argument from apply_to_page_range callback. > mm: add apply_to_page_range_batch() > ioremap: use apply_to_page_range_batch() for ioremap_page_range() > vmalloc: use plain pte_clear() for unmaps > vmalloc: use apply_to_page_range_batch() for vunmap_page_range() > vmalloc: use apply_to_page_range_batch() for > vmap_page_range_noflush() > vmalloc: use apply_to_page_range_batch() in alloc_vm_area() > xen/mmu: use apply_to_page_range_batch() in > xen_remap_domain_mfn_range() > xen/grant-table: use apply_to_page_range_batch() > > arch/x86/xen/grant-table.c | 30 +++++---- > arch/x86/xen/mmu.c | 18 +++-- > include/linux/mm.h | 9 ++- > lib/ioremap.c | 85 +++++++------------------ > mm/memory.c | 57 ++++++++++++----- > mm/vmalloc.c | 150 ++++++++++++-------------------------------- > 6 files changed, 140 insertions(+), 209 deletions(-) That all looks good to me. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>