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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 03/16] xen/x86: p2m-pod: Fix coding style for comments
On 09/21/2017 01:40 PM, Julien Grall wrote:
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Should probably add something like:
"While we're here, specify 1UL when shifting in a couple of cases."
This could be done on check-in.
Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxx>
>
> ---
>
> Cc: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
>
> Changes in v2:
> - Add Andrew's acked-by
> ---
> xen/arch/x86/mm/p2m-pod.c | 154
> ++++++++++++++++++++++++++++++----------------
> 1 file changed, 102 insertions(+), 52 deletions(-)
>
> diff --git a/xen/arch/x86/mm/p2m-pod.c b/xen/arch/x86/mm/p2m-pod.c
> index 1f07441259..6f045081b5 100644
> --- a/xen/arch/x86/mm/p2m-pod.c
> +++ b/xen/arch/x86/mm/p2m-pod.c
> @@ -155,8 +155,10 @@ static struct page_info * p2m_pod_cache_get(struct
> p2m_domain *p2m,
>
> BUG_ON( page_list_empty(&p2m->pod.super) );
>
> - /* Break up a superpage to make single pages. NB count doesn't
> - * need to be adjusted. */
> + /*
> + * Break up a superpage to make single pages. NB count doesn't
> + * need to be adjusted.
> + */
> p = page_list_remove_head(&p2m->pod.super);
> mfn = mfn_x(page_to_mfn(p));
>
> @@ -242,8 +244,10 @@ p2m_pod_set_cache_target(struct p2m_domain *p2m,
> unsigned long pod_target, int p
> }
>
> /* Decreasing the target */
> - /* We hold the pod lock here, so we don't need to worry about
> - * cache disappearing under our feet. */
> + /*
> + * We hold the pod lock here, so we don't need to worry about
> + * cache disappearing under our feet.
> + */
> while ( pod_target < p2m->pod.count )
> {
> struct page_info * page;
> @@ -345,15 +349,19 @@ p2m_pod_set_mem_target(struct domain *d, unsigned long
> target)
> if ( d->is_dying )
> goto out;
>
> - /* T' < B: Don't reduce the cache size; let the balloon driver
> - * take care of it. */
> + /*
> + * T' < B: Don't reduce the cache size; let the balloon driver
> + * take care of it.
> + */
> if ( target < d->tot_pages )
> goto out;
>
> pod_target = target - populated;
>
> - /* B < T': Set the cache size equal to # of outstanding entries,
> - * let the balloon driver fill in the rest. */
> + /*
> + * B < T': Set the cache size equal to # of outstanding entries,
> + * let the balloon driver fill in the rest.
> + */
> if ( populated > 0 && pod_target > p2m->pod.entry_count )
> pod_target = p2m->pod.entry_count;
>
> @@ -491,7 +499,8 @@ static int
> p2m_pod_zero_check_superpage(struct p2m_domain *p2m, unsigned long gfn);
>
>
> -/* This function is needed for two reasons:
> +/*
> + * This function is needed for two reasons:
> * + To properly handle clearing of PoD entries
> * + To "steal back" memory being freed for the PoD cache, rather than
> * releasing it.
> @@ -513,8 +522,10 @@ p2m_pod_decrease_reservation(struct domain *d,
> gfn_lock(p2m, gpfn, order);
> pod_lock(p2m);
>
> - /* If we don't have any outstanding PoD entries, let things take their
> - * course */
> + /*
> + * If we don't have any outstanding PoD entries, let things take their
> + * course.
> + */
> if ( p2m->pod.entry_count == 0 )
> goto out_unlock;
>
> @@ -550,8 +561,10 @@ p2m_pod_decrease_reservation(struct domain *d,
>
> if ( !nonpod )
> {
> - /* All PoD: Mark the whole region invalid and tell caller
> - * we're done. */
> + /*
> + * All PoD: Mark the whole region invalid and tell caller
> + * we're done.
> + */
> p2m_set_entry(p2m, gpfn, INVALID_MFN, order, p2m_invalid,
> p2m->default_access);
> p2m->pod.entry_count-=(1<<order);
> @@ -568,15 +581,16 @@ p2m_pod_decrease_reservation(struct domain *d,
> * - order >= SUPERPAGE_ORDER (the loop below will take care of this)
> * - not all of the pages were RAM (now knowing order < SUPERPAGE_ORDER)
> */
> - if ( steal_for_cache && order < SUPERPAGE_ORDER && ram == (1 << order) &&
> + if ( steal_for_cache && order < SUPERPAGE_ORDER && ram == (1UL << order)
> &&
> p2m_pod_zero_check_superpage(p2m, gpfn & ~(SUPERPAGE_PAGES - 1)) )
> {
> - pod = 1 << order;
> + pod = 1UL << order;
> ram = nonpod = 0;
> ASSERT(steal_for_cache == (p2m->pod.entry_count > p2m->pod.count));
> }
>
> - /* Process as long as:
> + /*
> + * Process as long as:
> * + There are PoD entries to handle, or
> * + There is ram left, and we want to steal it
> */
> @@ -631,8 +645,10 @@ p2m_pod_decrease_reservation(struct domain *d,
> }
> }
>
> - /* If there are no more non-PoD entries, tell decrease_reservation() that
> - * there's nothing left to do. */
> + /*
> + * If there are no more non-PoD entries, tell decrease_reservation() that
> + * there's nothing left to do.
> + */
> if ( nonpod == 0 )
> ret = 1;
>
> @@ -658,9 +674,11 @@ void p2m_pod_dump_data(struct domain *d)
> }
>
>
> -/* Search for all-zero superpages to be reclaimed as superpages for the
> +/*
> + * Search for all-zero superpages to be reclaimed as superpages for the
> * PoD cache. Must be called w/ pod lock held, must lock the superpage
> - * in the p2m */
> + * in the p2m.
> + */
> static int
> p2m_pod_zero_check_superpage(struct p2m_domain *p2m, unsigned long gfn)
> {
> @@ -682,12 +700,16 @@ p2m_pod_zero_check_superpage(struct p2m_domain *p2m,
> unsigned long gfn)
> if ( paging_mode_shadow(d) )
> max_ref++;
>
> - /* NOTE: this is why we don't enforce deadlock constraints between p2m
> - * and pod locks */
> + /*
> + * NOTE: this is why we don't enforce deadlock constraints between p2m
> + * and pod locks.
> + */
> gfn_lock(p2m, gfn, SUPERPAGE_ORDER);
>
> - /* Look up the mfns, checking to make sure they're the same mfn
> - * and aligned, and mapping them. */
> + /*
> + * Look up the mfns, checking to make sure they're the same mfn
> + * and aligned, and mapping them.
> + */
> for ( i = 0; i < SUPERPAGE_PAGES; i += n )
> {
> p2m_access_t a;
> @@ -697,7 +719,8 @@ p2m_pod_zero_check_superpage(struct p2m_domain *p2m,
> unsigned long gfn)
>
> mfn = p2m->get_entry(p2m, gfn + i, &type, &a, 0, &cur_order, NULL);
>
> - /* Conditions that must be met for superpage-superpage:
> + /*
> + * Conditions that must be met for superpage-superpage:
> * + All gfns are ram types
> * + All gfns have the same type
> * + All of the mfns are allocated to a domain
> @@ -751,9 +774,11 @@ p2m_pod_zero_check_superpage(struct p2m_domain *p2m,
> unsigned long gfn)
> p2m_populate_on_demand, p2m->default_access);
> p2m_tlb_flush_sync(p2m);
>
> - /* Make none of the MFNs are used elsewhere... for example, mapped
> + /*
> + * Make none of the MFNs are used elsewhere... for example, mapped
> * via the grant table interface, or by qemu. Allow one refcount for
> - * being allocated to the domain. */
> + * being allocated to the domain.
> + */
> for ( i=0; i < SUPERPAGE_PAGES; i++ )
> {
> mfn = _mfn(mfn_x(mfn0) + i);
> @@ -797,8 +822,10 @@ p2m_pod_zero_check_superpage(struct p2m_domain *p2m,
> unsigned long gfn)
> __trace_var(TRC_MEM_POD_ZERO_RECLAIM, 0, sizeof(t), &t);
> }
>
> - /* Finally! We've passed all the checks, and can add the mfn superpage
> - * back on the PoD cache, and account for the new p2m PoD entries */
> + /*
> + * Finally! We've passed all the checks, and can add the mfn superpage
> + * back on the PoD cache, and account for the new p2m PoD entries.
> + */
> p2m_pod_cache_add(p2m, mfn_to_page(mfn0), PAGE_ORDER_2M);
> p2m->pod.entry_count += SUPERPAGE_PAGES;
>
> @@ -833,8 +860,10 @@ p2m_pod_zero_check(struct p2m_domain *p2m, unsigned long
> *gfns, int count)
> {
> p2m_access_t a;
> mfns[i] = p2m->get_entry(p2m, gfns[i], types + i, &a, 0, NULL, NULL);
> - /* If this is ram, and not a pagetable or from the xen heap, and
> probably not mapped
> - elsewhere, map it; otherwise, skip. */
> + /*
> + * If this is ram, and not a pagetable or from the xen heap, and
> + * probably not mapped elsewhere, map it; otherwise, skip.
> + */
> if ( p2m_is_ram(types[i])
> && ( (mfn_to_page(mfns[i])->count_info & PGC_allocated) != 0 )
> && ( (mfn_to_page(mfns[i])->count_info &
> (PGC_page_table|PGC_xen_heap)) == 0 )
> @@ -844,8 +873,10 @@ p2m_pod_zero_check(struct p2m_domain *p2m, unsigned long
> *gfns, int count)
> map[i] = NULL;
> }
>
> - /* Then, go through and check for zeroed pages, removing write permission
> - * for those with zeroes. */
> + /*
> + * Then, go through and check for zeroed pages, removing write permission
> + * for those with zeroes.
> + */
> for ( i=0; i<count; i++ )
> {
> if(!map[i])
> @@ -867,8 +898,10 @@ p2m_pod_zero_check(struct p2m_domain *p2m, unsigned long
> *gfns, int count)
> p2m_set_entry(p2m, gfns[i], INVALID_MFN, PAGE_ORDER_4K,
> p2m_populate_on_demand, p2m->default_access);
>
> - /* See if the page was successfully unmapped. (Allow one refcount
> - * for being allocated to a domain.) */
> + /*
> + * See if the page was successfully unmapped. (Allow one refcount
> + * for being allocated to a domain.)
> + */
> if ( (mfn_to_page(mfns[i])->count_info & PGC_count_mask) > 1 )
> {
> unmap_domain_page(map[i]);
> @@ -895,8 +928,10 @@ p2m_pod_zero_check(struct p2m_domain *p2m, unsigned long
> *gfns, int count)
>
> unmap_domain_page(map[i]);
>
> - /* See comment in p2m_pod_zero_check_superpage() re gnttab
> - * check timing. */
> + /*
> + * See comment in p2m_pod_zero_check_superpage() re gnttab
> + * check timing.
> + */
> if ( j < PAGE_SIZE/sizeof(*map[i]) )
> {
> p2m_set_entry(p2m, gfns[i], mfns[i], PAGE_ORDER_4K,
> @@ -944,9 +979,11 @@ p2m_pod_emergency_sweep(struct p2m_domain *p2m)
> limit = (start > POD_SWEEP_LIMIT) ? (start - POD_SWEEP_LIMIT) : 0;
>
> /* FIXME: Figure out how to avoid superpages */
> - /* NOTE: Promote to globally locking the p2m. This will get complicated
> + /*
> + * NOTE: Promote to globally locking the p2m. This will get complicated
> * in a fine-grained scenario. If we lock each gfn individually we must
> be
> - * careful about spinlock recursion limits and POD_SWEEP_STRIDE. */
> + * careful about spinlock recursion limits and POD_SWEEP_STRIDE.
> + */
> p2m_lock(p2m);
> for ( i=p2m->pod.reclaim_single; i > 0 ; i-- )
> {
> @@ -963,11 +1000,13 @@ p2m_pod_emergency_sweep(struct p2m_domain *p2m)
> j = 0;
> }
> }
> - /* Stop if we're past our limit and we have found *something*.
> + /*
> + * Stop if we're past our limit and we have found *something*.
> *
> * NB that this is a zero-sum game; we're increasing our cache size
> * by re-increasing our 'debt'. Since we hold the pod lock,
> - * (entry_count - count) must remain the same. */
> + * (entry_count - count) must remain the same.
> + */
> if ( i < limit && (p2m->pod.count > 0 || hypercall_preempt_check()) )
> break;
> }
> @@ -1045,20 +1084,25 @@ p2m_pod_demand_populate(struct p2m_domain *p2m,
> unsigned long gfn,
> ASSERT(gfn_locked_by_me(p2m, gfn));
> pod_lock(p2m);
>
> - /* This check is done with the pod lock held. This will make sure that
> + /*
> + * This check is done with the pod lock held. This will make sure that
> * even if d->is_dying changes under our feet, p2m_pod_empty_cache()
> - * won't start until we're done. */
> + * won't start until we're done.
> + */
> if ( unlikely(d->is_dying) )
> goto out_fail;
>
>
> - /* Because PoD does not have cache list for 1GB pages, it has to remap
> - * 1GB region to 2MB chunks for a retry. */
> + /*
> + * Because PoD does not have cache list for 1GB pages, it has to remap
> + * 1GB region to 2MB chunks for a retry.
> + */
> if ( order == PAGE_ORDER_1G )
> {
> pod_unlock(p2m);
> gfn_aligned = (gfn >> order) << order;
> - /* Note that we are supposed to call p2m_set_entry() 512 times to
> + /*
> + * Note that we are supposed to call p2m_set_entry() 512 times to
> * split 1GB into 512 2MB pages here. But We only do once here
> because
> * p2m_set_entry() should automatically shatter the 1GB page into
> * 512 2MB pages. The rest of 511 calls are unnecessary.
> @@ -1075,8 +1119,10 @@ p2m_pod_demand_populate(struct p2m_domain *p2m,
> unsigned long gfn,
> if ( p2m->pod.entry_count > p2m->pod.count )
> pod_eager_reclaim(p2m);
>
> - /* Only sweep if we're actually out of memory. Doing anything else
> - * causes unnecessary time and fragmentation of superpages in the p2m. */
> + /*
> + * Only sweep if we're actually out of memory. Doing anything else
> + * causes unnecessary time and fragmentation of superpages in the p2m.
> + */
> if ( p2m->pod.count == 0 )
> p2m_pod_emergency_sweep(p2m);
>
> @@ -1088,8 +1134,10 @@ p2m_pod_demand_populate(struct p2m_domain *p2m,
> unsigned long gfn,
> if ( gfn > p2m->pod.max_guest )
> p2m->pod.max_guest = gfn;
>
> - /* Get a page f/ the cache. A NULL return value indicates that the
> - * 2-meg range should be marked singleton PoD, and retried */
> + /*
> + * Get a page f/ the cache. A NULL return value indicates that the
> + * 2-meg range should be marked singleton PoD, and retried.
> + */
> if ( (p = p2m_pod_cache_get(p2m, order)) == NULL )
> goto remap_and_retry;
>
> @@ -1146,8 +1194,10 @@ remap_and_retry:
> pod_unlock(p2m);
>
> /* Remap this 2-meg region in singleton chunks */
> - /* NOTE: In a p2m fine-grained lock scenario this might
> - * need promoting the gfn lock from gfn->2M superpage */
> + /*
> + * NOTE: In a p2m fine-grained lock scenario this might
> + * need promoting the gfn lock from gfn->2M superpage.
> + */
> gfn_aligned = (gfn>>order)<<order;
> for(i=0; i<(1<<order); i++)
> p2m_set_entry(p2m, gfn_aligned + i, INVALID_MFN, PAGE_ORDER_4K,
>
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