On 09/20/2016 02:54 PM, Nicholas Piggin wrote: > On Tue, 20 Sep 2016 14:02:26 +0800 > zijun_hu <zijun_hu@xxxxxxxx> wrote: > >> From: zijun_hu <zijun_hu@xxxxxxx> >> >> correct a few logic error in __insert_vmap_area() since the else if >> condition is always true and meaningless >> >> avoid endless loop under [un]mapping improper ranges whose boundary >> are not aligned to page >> >> correct lazy_max_pages() return value if the number of online cpus >> is power of 2 >> >> improve performance for pcpu_get_vm_areas() via optimizing vmap_areas >> overlay checking algorithm and finding near vmap_areas by list_head >> other than rbtree >> >> simplify /proc/vmallocinfo implementation via seq_file helpers >> for list_head >> >> Signed-off-by: zijun_hu <zijun_hu@xxxxxxx> >> Signed-off-by: zijun_hu <zijun_hu@xxxxxxxx> > > Could you submit each of these changes as a separate patch? Would you > consider using capitalisation and punctuation in the changelog? > thanks for your advisement i will follow it and split this patch to smaller patches finally > Did you measure any performance improvements, or do you have a workload > where vmalloc shows up in profiles? > don't have measurement in practice, but i am sure there are performance improvements for pcpu_get_vm_areas() theoretically due to below reasons: 1) the counter of vmap_area overlay checkup loop is reduced to half 2) the previous and next vmap_area of one on list_head are just the nearest ones due to address sorted vmap_areas on list_head, so no walk and compare is needed > >> @@ -108,6 +108,9 @@ static void vunmap_page_range(unsigned long addr, unsigned long end) >> unsigned long next; >> >> BUG_ON(addr >= end); >> + WARN_ON(!PAGE_ALIGNED(addr | end)); > > I prefer to avoid mixing bitwise and arithmetic operations unless it's > necessary. Gcc should be able to optimise > > WARN_ON(!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(end)) > i agree with you, i will apply your suggestion finally >> + addr = round_down(addr, PAGE_SIZE); > > I don't know if it's really necessary to relax the API like this for > internal vmalloc.c functions. If garbage is detected here, it's likely > due to a bug, and I'm not sure that rounding it would solve the problem. > > For API functions perhaps it's reasonable -- in such cases you should > consider using WARN_ON_ONCE() or similar. > actually, another patch for API function within /lib/ioremap.c used the way as pointed by you as below, i am not sure which is better, perhaps i will exchange each other Subject: [PATCH 2/3] lib/ioremap.c: avoid endless loop under ioremapping improper ranges for ioremap_page_range(), endless loop maybe happen if either of parameter addr and end is not page aligned, in order to fix this issue and hint range parameter requirements BUG_ON() checkup are performed firstly for ioremap_pte_range(), loop end condition is optimized due to lack of relevant macro pte_addr_end() Signed-off-by: zijun_hu <zijun_hu@xxxxxxx> --- lib/ioremap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/lib/ioremap.c b/lib/ioremap.c index 86c8911..0058cc8 100644 --- a/lib/ioremap.c +++ b/lib/ioremap.c @@ -64,7 +64,7 @@ static int ioremap_pte_range(pmd_t *pmd, unsigned long addr, BUG_ON(!pte_none(*pte)); set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot)); pfn++; - } while (pte++, addr += PAGE_SIZE, addr != end); + } while (pte++, addr += PAGE_SIZE, addr < end); return 0; } @@ -129,6 +129,7 @@ int ioremap_page_range(unsigned long addr, int err; BUG_ON(addr >= end); + BUG_ON(!PAGE_ALIGNED(addr | end)); start = addr; phys_addr -= addr; > Thanks, > Nick > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>