| Message ID | 20220909092451.24883-2-linmiaohe@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | A few cleanup patches for mm | expand |
On 09.09.22 11:24, Miaohe Lin wrote: > If ALLOC_KSWAPD is set, wake_all_kswapds() will be called to ensure > kswapd doesn't accidentally go to sleep. But when reserve_flags is > set, alloc_flags will be overwritten and ALLOC_KSWAPD is thus lost. > Preserve the ALLOC_KSWAPD flag in alloc_flags to ensure kswapd won't > go to sleep accidentally. > > Fixes: 0a79cdad5eb2 ("mm: use alloc_flags to record if kswapd can wake") > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> > --- > mm/page_alloc.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index ba5c9402a5cb..4b97a03fa2dd 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -5147,7 +5147,8 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, > > reserve_flags = __gfp_pfmemalloc_flags(gfp_mask); > if (reserve_flags) > - alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags); > + alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags) | > + (alloc_flags & ALLOC_KSWAPD); > > /* > * Reset the nodemask and zonelist iterators if memory policies can be Acked-by: David Hildenbrand <david@redhat.com>
On 9/9/22 14:54, Miaohe Lin wrote: > If ALLOC_KSWAPD is set, wake_all_kswapds() will be called to ensure > kswapd doesn't accidentally go to sleep. But when reserve_flags is > set, alloc_flags will be overwritten and ALLOC_KSWAPD is thus lost. > Preserve the ALLOC_KSWAPD flag in alloc_flags to ensure kswapd won't > go to sleep accidentally. Currently wake_all_kswapds() gets skipped subsequently if ALLOC_KSWAPD is lost, but this only happens when the 'retry:' loops is taken ? > > Fixes: 0a79cdad5eb2 ("mm: use alloc_flags to record if kswapd can wake") > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> > --- > mm/page_alloc.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index ba5c9402a5cb..4b97a03fa2dd 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -5147,7 +5147,8 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, > > reserve_flags = __gfp_pfmemalloc_flags(gfp_mask); > if (reserve_flags) > - alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags); > + alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags) | > + (alloc_flags & ALLOC_KSWAPD); > > /* > * Reset the nodemask and zonelist iterators if memory policies can be
On Tue, Sep 13, 2022 at 12:32:50PM +0530, Anshuman Khandual wrote: > > > On 9/9/22 14:54, Miaohe Lin wrote: > > If ALLOC_KSWAPD is set, wake_all_kswapds() will be called to ensure > > kswapd doesn't accidentally go to sleep. But when reserve_flags is > > set, alloc_flags will be overwritten and ALLOC_KSWAPD is thus lost. > > Preserve the ALLOC_KSWAPD flag in alloc_flags to ensure kswapd won't > > go to sleep accidentally. > > Currently wake_all_kswapds() gets skipped subsequently if ALLOC_KSWAPD > is lost, but this only happens when the 'retry:' loops is taken ? Right, but see the comment: /* Ensure kswapd doesn't accidentally go to sleep as long as we loop */ and that is not currently true. I think that was an inadvertent change. Particularly since the changelog for 0a79cdad5eb2 says "No functional change". > > > > Fixes: 0a79cdad5eb2 ("mm: use alloc_flags to record if kswapd can wake") > > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> > > --- > > mm/page_alloc.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index ba5c9402a5cb..4b97a03fa2dd 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -5147,7 +5147,8 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, > > > > reserve_flags = __gfp_pfmemalloc_flags(gfp_mask); > > if (reserve_flags) > > - alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags); > > + alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags) | > > + (alloc_flags & ALLOC_KSWAPD); > > > > /* > > * Reset the nodemask and zonelist iterators if memory policies can be >
On 9/13/22 13:28, Matthew Wilcox wrote: > On Tue, Sep 13, 2022 at 12:32:50PM +0530, Anshuman Khandual wrote: >> >> On 9/9/22 14:54, Miaohe Lin wrote: >>> If ALLOC_KSWAPD is set, wake_all_kswapds() will be called to ensure >>> kswapd doesn't accidentally go to sleep. But when reserve_flags is >>> set, alloc_flags will be overwritten and ALLOC_KSWAPD is thus lost. >>> Preserve the ALLOC_KSWAPD flag in alloc_flags to ensure kswapd won't >>> go to sleep accidentally. >> Currently wake_all_kswapds() gets skipped subsequently if ALLOC_KSWAPD >> is lost, but this only happens when the 'retry:' loops is taken ? > Right, but see the comment: > > /* Ensure kswapd doesn't accidentally go to sleep as long as we loop */ > > and that is not currently true. I think that was an inadvertent change. > Particularly since the changelog for 0a79cdad5eb2 says "No functional > change". Got it, thanks for the explanation.
On Fri, Sep 09, 2022 at 05:24:36PM +0800, Miaohe Lin wrote: > If ALLOC_KSWAPD is set, wake_all_kswapds() will be called to ensure > kswapd doesn't accidentally go to sleep. But when reserve_flags is > set, alloc_flags will be overwritten and ALLOC_KSWAPD is thus lost. > Preserve the ALLOC_KSWAPD flag in alloc_flags to ensure kswapd won't > go to sleep accidentally. > > Fixes: 0a79cdad5eb2 ("mm: use alloc_flags to record if kswapd can wake") > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> > --- > mm/page_alloc.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index ba5c9402a5cb..4b97a03fa2dd 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -5147,7 +5147,8 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, > > reserve_flags = __gfp_pfmemalloc_flags(gfp_mask); > if (reserve_flags) > - alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags); > + alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags) | > + (alloc_flags & ALLOC_KSWAPD); > > /* > * Reset the nodemask and zonelist iterators if memory policies can be > -- > 2.23.0 >
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index ba5c9402a5cb..4b97a03fa2dd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5147,7 +5147,8 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, reserve_flags = __gfp_pfmemalloc_flags(gfp_mask); if (reserve_flags) - alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags); + alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags) | + (alloc_flags & ALLOC_KSWAPD); /* * Reset the nodemask and zonelist iterators if memory policies can be
If ALLOC_KSWAPD is set, wake_all_kswapds() will be called to ensure kswapd doesn't accidentally go to sleep. But when reserve_flags is set, alloc_flags will be overwritten and ALLOC_KSWAPD is thus lost. Preserve the ALLOC_KSWAPD flag in alloc_flags to ensure kswapd won't go to sleep accidentally. Fixes: 0a79cdad5eb2 ("mm: use alloc_flags to record if kswapd can wake") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> --- mm/page_alloc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)