Messages in this thread | | | Date | Tue, 27 Mar 2012 10:31:42 -0400 | From | Konrad Rzeszutek Wilk <> | Subject | Re: [PATCH 1/2] xen: enter/exit lazy_mmu_mode around m2p_override calls |
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On Tue, Mar 27, 2012 at 02:52:43PM +0100, Stefano Stabellini wrote: > This patch is a significant performance improvement for the
How much? 10%? 90%?
> m2p_override.
Can you explain what those calls do in the git commit description please?
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > --- > drivers/block/xen-blkback/blkback.c | 4 ++++ > drivers/xen/grant-table.c | 8 ++++++++ > 2 files changed, 12 insertions(+), 0 deletions(-) > > diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c > index 0088bf6..60abff6 100644 > --- a/drivers/block/xen-blkback/blkback.c > +++ b/drivers/block/xen-blkback/blkback.c > @@ -342,6 +342,7 @@ static void xen_blkbk_unmap(struct pending_req *req) > * Note, we use invcount, so nr->pages, so we can't index > * using vaddr(req, i). > */ > + arch_enter_lazy_mmu_mode(); > for (i = 0; i < invcount; i++) { > ret = m2p_remove_override( > virt_to_page(unmap[i].host_addr), false); > @@ -351,6 +352,7 @@ static void xen_blkbk_unmap(struct pending_req *req) > continue; > } > } > + arch_leave_lazy_mmu_mode(); > } > > static int xen_blkbk_map(struct blkif_request *req, > @@ -386,6 +388,7 @@ static int xen_blkbk_map(struct blkif_request *req, > * so that when we access vaddr(pending_req,i) it has the contents of > * the page from the other domain. > */ > + arch_enter_lazy_mmu_mode(); > for (i = 0; i < nseg; i++) { > if (unlikely(map[i].status != 0)) { > pr_debug(DRV_PFX "invalid buffer -- could not remap it\n"); > @@ -410,6 +413,7 @@ static int xen_blkbk_map(struct blkif_request *req, > seg[i].buf = map[i].dev_bus_addr | > (req->u.rw.seg[i].first_sect << 9); > } > + arch_leave_lazy_mmu_mode(); > return ret; > } > > diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c > index b4d4eac..c7dc2d6 100644 > --- a/drivers/xen/grant-table.c > +++ b/drivers/xen/grant-table.c > @@ -751,6 +751,8 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, > if (xen_feature(XENFEAT_auto_translated_physmap)) > return ret; > > + arch_enter_lazy_mmu_mode(); > + > for (i = 0; i < count; i++) { > /* Do not add to override if the map failed. */ > if (map_ops[i].status) > @@ -769,6 +771,8 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, > return ret; > } > > + arch_leave_lazy_mmu_mode(); > + > return ret; > } > EXPORT_SYMBOL_GPL(gnttab_map_refs); > @@ -785,12 +789,16 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, > if (xen_feature(XENFEAT_auto_translated_physmap)) > return ret; > > + arch_enter_lazy_mmu_mode(); > + > for (i = 0; i < count; i++) { > ret = m2p_remove_override(pages[i], clear_pte); > if (ret) > return ret; > } > > + arch_leave_lazy_mmu_mode(); > + > return ret; > } > EXPORT_SYMBOL_GPL(gnttab_unmap_refs); > -- > 1.7.2.5 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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