| Message ID | 20200907163628.26495-4-vbabka@suse.cz (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | disable pcplists during page isolation | expand |
On Mon, Sep 07, 2020 at 06:36:26PM +0200, Vlastimil Babka wrote: > We initialize boot-time pagesets with setup_pageset(), which sets high and > batch values that effectively disable pcplists. > > We can remove this wrapper if we just set these values for all pagesets in > pageset_init(). Non-boot pagesets then subsequently update them to specific > values. > > Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Oscar Salvador <osalvador@suse.de> Just one question below: > -static void setup_pageset(struct per_cpu_pageset *p) > -{ > - pageset_init(p); > - pageset_update(&p->pcp, 0, 1); > + /* > + * Set batch and high values safe for a boot pageset. Proper pageset's > + * initialization will update them. > + */ > + pcp->high = 0; > + pcp->batch = 1; pageset_update was manipulating these values with barriers in between. I guess we do not care here because we are not really updating but initializing them, right?
On Thu, Sep 10, 2020 at 11:23:07AM +0200, Oscar Salvador wrote: > On Mon, Sep 07, 2020 at 06:36:26PM +0200, Vlastimil Babka wrote: > > We initialize boot-time pagesets with setup_pageset(), which sets high and > > batch values that effectively disable pcplists. > > > > We can remove this wrapper if we just set these values for all pagesets in > > pageset_init(). Non-boot pagesets then subsequently update them to specific > > values. > > > > Signed-off-by: Vlastimil Babka <vbabka@suse.cz> > > Reviewed-by: Oscar Salvador <osalvador@suse.de> You would need to squash here the remove of setup_pageset's declaration. And then remove it from patch#4.
On 07.09.20 18:36, Vlastimil Babka wrote: > We initialize boot-time pagesets with setup_pageset(), which sets high and > batch values that effectively disable pcplists. > > We can remove this wrapper if we just set these values for all pagesets in > pageset_init(). Non-boot pagesets then subsequently update them to specific > values. > subject: s/page_alloc()/page_alloc/ to make it look consistent > Signed-off-by: Vlastimil Babka <vbabka@suse.cz> > --- > mm/page_alloc.c | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index f669a251f654..a0cab2c6055e 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -5902,7 +5902,7 @@ build_all_zonelists_init(void) > * (a chicken-egg dilemma). > */ > for_each_possible_cpu(cpu) > - setup_pageset(&per_cpu(boot_pageset, cpu)); > + pageset_init(&per_cpu(boot_pageset, cpu)); > > mminit_verify_zonelist(); > cpuset_init_current_mems_allowed(); > @@ -6228,12 +6228,13 @@ static void pageset_init(struct per_cpu_pageset *p) > pcp = &p->pcp; > for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++) > INIT_LIST_HEAD(&pcp->lists[migratetype]); > -} > > -static void setup_pageset(struct per_cpu_pageset *p) > -{ > - pageset_init(p); > - pageset_update(&p->pcp, 0, 1); > + /* > + * Set batch and high values safe for a boot pageset. Proper pageset's > + * initialization will update them. > + */ > + pcp->high = 0; > + pcp->batch = 1; > } > > static void zone_set_pageset_high_and_batch(struct zone *zone) > Had the same thought about barriers being useless when the pageset is not hot. LGTM Reviewed-by: David Hildenbrand <david@redhat.com>
On 9/10/20 11:23 AM, Oscar Salvador wrote: > On Mon, Sep 07, 2020 at 06:36:26PM +0200, Vlastimil Babka wrote: >> We initialize boot-time pagesets with setup_pageset(), which sets high and >> batch values that effectively disable pcplists. >> >> We can remove this wrapper if we just set these values for all pagesets in >> pageset_init(). Non-boot pagesets then subsequently update them to specific >> values. >> >> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> > > Reviewed-by: Oscar Salvador <osalvador@suse.de> Thanks! > Just one question below: > >> -static void setup_pageset(struct per_cpu_pageset *p) >> -{ >> - pageset_init(p); >> - pageset_update(&p->pcp, 0, 1); >> + /* >> + * Set batch and high values safe for a boot pageset. Proper pageset's >> + * initialization will update them. >> + */ >> + pcp->high = 0; >> + pcp->batch = 1; > > pageset_update was manipulating these values with barriers in between. > I guess we do not care here because we are not really updating but > initializing them, right? Sure. We just initialized all the list heads, so there can be no concurrent access at this point. But I'll mention it in the comment.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index f669a251f654..a0cab2c6055e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5902,7 +5902,7 @@ build_all_zonelists_init(void) * (a chicken-egg dilemma). */ for_each_possible_cpu(cpu) - setup_pageset(&per_cpu(boot_pageset, cpu)); + pageset_init(&per_cpu(boot_pageset, cpu)); mminit_verify_zonelist(); cpuset_init_current_mems_allowed(); @@ -6228,12 +6228,13 @@ static void pageset_init(struct per_cpu_pageset *p) pcp = &p->pcp; for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++) INIT_LIST_HEAD(&pcp->lists[migratetype]); -} -static void setup_pageset(struct per_cpu_pageset *p) -{ - pageset_init(p); - pageset_update(&p->pcp, 0, 1); + /* + * Set batch and high values safe for a boot pageset. Proper pageset's + * initialization will update them. + */ + pcp->high = 0; + pcp->batch = 1; } static void zone_set_pageset_high_and_batch(struct zone *zone)
We initialize boot-time pagesets with setup_pageset(), which sets high and batch values that effectively disable pcplists. We can remove this wrapper if we just set these values for all pagesets in pageset_init(). Non-boot pagesets then subsequently update them to specific values. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> --- mm/page_alloc.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)