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charset=us-ascii Content-Disposition: inline In-Reply-To: <20230113111217.14134-6-mgorman@techsingularity.net> X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: rp67js553b53icinkghbz8im6ogbut8u X-Rspamd-Queue-Id: 313B94001F X-HE-Tag: 1673615174-912836 X-HE-Meta: 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 ThtFITNF u4uPhtDudgng6tRU= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri 13-01-23 11:12:16, Mel Gorman wrote: > GFP_ATOMIC allocations get flagged ALLOC_HARDER which is a vague > description. In preparation for the removal of GFP_ATOMIC redefine > __GFP_ATOMIC to simply mean non-blocking and renaming ALLOC_HARDER to > ALLOC_NON_BLOCK accordingly. __GFP_HIGH is required for access to reserves > but non-blocking is granted more access. For example, GFP_NOWAIT is > non-blocking but has no special access to reserves. A __GFP_NOFAIL > blocking allocation is granted access similar to __GFP_HIGH if the > only alternative is an OOM kill. > > Signed-off-by: Mel Gorman Acked-by: Michal Hocko Thanks! > --- > mm/internal.h | 7 +++++-- > mm/page_alloc.c | 44 ++++++++++++++++++++++++-------------------- > 2 files changed, 29 insertions(+), 22 deletions(-) > > diff --git a/mm/internal.h b/mm/internal.h > index 8706d46863df..23a37588073a 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -735,7 +735,10 @@ unsigned int reclaim_clean_pages_from_list(struct zone *zone, > #define ALLOC_OOM ALLOC_NO_WATERMARKS > #endif > > -#define ALLOC_HARDER 0x10 /* try to alloc harder */ > +#define ALLOC_NON_BLOCK 0x10 /* Caller cannot block. Allow access > + * to 25% of the min watermark or > + * 62.5% if __GFP_HIGH is set. > + */ > #define ALLOC_MIN_RESERVE 0x20 /* __GFP_HIGH set. Allow access to 50% > * of the min watermark. > */ > @@ -750,7 +753,7 @@ unsigned int reclaim_clean_pages_from_list(struct zone *zone, > #define ALLOC_KSWAPD 0x800 /* allow waking of kswapd, __GFP_KSWAPD_RECLAIM set */ > > /* Flags that allow allocations below the min watermark. */ > -#define ALLOC_RESERVES (ALLOC_HARDER|ALLOC_MIN_RESERVE|ALLOC_HIGHATOMIC|ALLOC_OOM) > +#define ALLOC_RESERVES (ALLOC_NON_BLOCK|ALLOC_MIN_RESERVE|ALLOC_HIGHATOMIC|ALLOC_OOM) > > enum ttu_flags; > struct tlbflush_unmap_batch; > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 6f41b84a97ac..b9ae0ba0a2ab 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -3989,18 +3989,19 @@ bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, > * __GFP_HIGH allows access to 50% of the min reserve as well > * as OOM. > */ > - if (alloc_flags & ALLOC_MIN_RESERVE) > + if (alloc_flags & ALLOC_MIN_RESERVE) { > min -= min / 2; > > - /* > - * Non-blocking allocations can access some of the reserve > - * with more access if also __GFP_HIGH. The reasoning is that > - * a non-blocking caller may incur a more severe penalty > - * if it cannot get memory quickly, particularly if it's > - * also __GFP_HIGH. > - */ > - if (alloc_flags & ALLOC_HARDER) > - min -= min / 4; > + /* > + * Non-blocking allocations (e.g. GFP_ATOMIC) can > + * access more reserves than just __GFP_HIGH. Other > + * non-blocking allocations requests such as GFP_NOWAIT > + * or (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) do not get > + * access to the min reserve. > + */ > + if (alloc_flags & ALLOC_NON_BLOCK) > + min -= min / 4; > + } > > /* > * OOM victims can try even harder than the normal reserve > @@ -4851,28 +4852,30 @@ gfp_to_alloc_flags(gfp_t gfp_mask, unsigned int order) > * The caller may dip into page reserves a bit more if the caller > * cannot run direct reclaim, or if the caller has realtime scheduling > * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will > - * set both ALLOC_HARDER (__GFP_ATOMIC) and ALLOC_MIN_RESERVE(__GFP_HIGH). > + * set both ALLOC_NON_BLOCK and ALLOC_MIN_RESERVE(__GFP_HIGH). > */ > alloc_flags |= (__force int) > (gfp_mask & (__GFP_HIGH | __GFP_KSWAPD_RECLAIM)); > > - if (gfp_mask & __GFP_ATOMIC) { > + if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) { > /* > * Not worth trying to allocate harder for __GFP_NOMEMALLOC even > * if it can't schedule. > */ > if (!(gfp_mask & __GFP_NOMEMALLOC)) { > - alloc_flags |= ALLOC_HARDER; > + alloc_flags |= ALLOC_NON_BLOCK; > > if (order > 0) > alloc_flags |= ALLOC_HIGHATOMIC; > } > > /* > - * Ignore cpuset mems for GFP_ATOMIC rather than fail, see the > - * comment for __cpuset_node_allowed(). > + * Ignore cpuset mems for non-blocking __GFP_HIGH (probably > + * GFP_ATOMIC) rather than fail, see the comment for > + * __cpuset_node_allowed(). > */ > - alloc_flags &= ~ALLOC_CPUSET; > + if (alloc_flags & ALLOC_MIN_RESERVE) > + alloc_flags &= ~ALLOC_CPUSET; > } else if (unlikely(rt_task(current)) && in_task()) > alloc_flags |= ALLOC_MIN_RESERVE; > > @@ -5303,12 +5306,13 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, > WARN_ON_ONCE_GFP(costly_order, gfp_mask); > > /* > - * Help non-failing allocations by giving them access to memory > - * reserves but do not use ALLOC_NO_WATERMARKS because this > + * Help non-failing allocations by giving some access to memory > + * reserves normally used for high priority non-blocking > + * allocations but do not use ALLOC_NO_WATERMARKS because this > * could deplete whole memory reserves which would just make > - * the situation worse > + * the situation worse. > */ > - page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_HARDER, ac); > + page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_MIN_RESERVE, ac); > if (page) > goto got_pg; > > -- > 2.35.3 -- Michal Hocko SUSE Labs