| Message ID | 20220217002227.5739-3-mgorman@techsingularity.net (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Follow-up on high-order PCP caching | expand |
On 2/17/22 01:22, Mel Gorman wrote: > free_pcppages_bulk() frees pages in a round-robin fashion. Originally, > this was dealing only with migratetypes but storing high-order pages > means that there can be many more empty lists that are uselessly > checked. Track the minimum and maximum active pindex to reduce the > search space. > > Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> > --- > mm/page_alloc.c | 17 +++++++++++++---- > 1 file changed, 13 insertions(+), 4 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 08de32cfd9bb..85cc1fe8bcc5 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1450,6 +1450,8 @@ static void free_pcppages_bulk(struct zone *zone, int count, > struct per_cpu_pages *pcp) > { > int pindex = 0; > + int min_pindex = 0; > + int max_pindex = NR_PCP_LISTS - 1; > int batch_free = 0; > int nr_freed = 0; > unsigned int order; > @@ -1475,13 +1477,20 @@ static void free_pcppages_bulk(struct zone *zone, int count, > */ > do { > batch_free++; > - if (++pindex == NR_PCP_LISTS) > - pindex = 0; > + if (++pindex > max_pindex) > + pindex = min_pindex; > list = &pcp->lists[pindex]; > - } while (list_empty(list)); > + if (!list_empty(list)) > + break; > + > + if (pindex == max_pindex) > + max_pindex--; > + if (pindex == min_pindex) > + min_pindex++; > + } while (1); > > /* This is the only non-empty list. Free them all. */ > - if (batch_free == NR_PCP_LISTS) > + if (batch_free >= max_pindex - min_pindex) > batch_free = count; > > order = pindex_to_order(pindex);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 08de32cfd9bb..85cc1fe8bcc5 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1450,6 +1450,8 @@ static void free_pcppages_bulk(struct zone *zone, int count, struct per_cpu_pages *pcp) { int pindex = 0; + int min_pindex = 0; + int max_pindex = NR_PCP_LISTS - 1; int batch_free = 0; int nr_freed = 0; unsigned int order; @@ -1475,13 +1477,20 @@ static void free_pcppages_bulk(struct zone *zone, int count, */ do { batch_free++; - if (++pindex == NR_PCP_LISTS) - pindex = 0; + if (++pindex > max_pindex) + pindex = min_pindex; list = &pcp->lists[pindex]; - } while (list_empty(list)); + if (!list_empty(list)) + break; + + if (pindex == max_pindex) + max_pindex--; + if (pindex == min_pindex) + min_pindex++; + } while (1); /* This is the only non-empty list. Free them all. */ - if (batch_free == NR_PCP_LISTS) + if (batch_free >= max_pindex - min_pindex) batch_free = count; order = pindex_to_order(pindex);
free_pcppages_bulk() frees pages in a round-robin fashion. Originally, this was dealing only with migratetypes but storing high-order pages means that there can be many more empty lists that are uselessly checked. Track the minimum and maximum active pindex to reduce the search space. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> --- mm/page_alloc.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-)