From: Andrew Morton <akpm@linux-foundation.org> To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name>, David Rientjes <rientjes@google.com>, Vlastimil Babka <vbabka@suse.cz>, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V3] mm/thp: Allocate transparent hugepages on local node Date: Fri, 16 Jan 2015 16:02:04 -0800 [thread overview] Message-ID: <20150116160204.544e2bcf9627f5a4043ebf8d@linux-foundation.org> (raw) In-Reply-To: <1421393196-20915-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> On Fri, 16 Jan 2015 12:56:36 +0530 "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote: > This make sure that we try to allocate hugepages from local node if > allowed by mempolicy. If we can't, we fallback to small page allocation > based on mempolicy. This is based on the observation that allocating pages > on local node is more beneficial than allocating hugepages on remote node. The changelog is a bit incomplete. It doesn't describe the current behaviour, nor what is wrong with it. What are the before-and-after effects of this change? And what might be the user-visible effects? > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -2030,6 +2030,46 @@ retry_cpuset: > return page; > } > > +struct page *alloc_hugepage_vma(gfp_t gfp, struct vm_area_struct *vma, > + unsigned long addr, int order) alloc_pages_vma() is nicely documented. alloc_hugepage_vma() is not documented at all. This makes it a bit had for readers to work out the difference! Is it possible to scrunch them both into the same function? Probably too messy? > +{ > + struct page *page; > + nodemask_t *nmask; > + struct mempolicy *pol; > + int node = numa_node_id(); > + unsigned int cpuset_mems_cookie; > + > +retry_cpuset: > + pol = get_vma_policy(vma, addr); > + cpuset_mems_cookie = read_mems_allowed_begin(); > + > + if (pol->mode != MPOL_INTERLEAVE) { > + /* > + * For interleave policy, we don't worry about > + * current node. Otherwise if current node is > + * in nodemask, try to allocate hugepage from > + * current node. Don't fall back to other nodes > + * for THP. > + */ This code isn't "interleave policy". It's everything *but* interleave policy. Comment makes no sense! > + nmask = policy_nodemask(gfp, pol); > + if (!nmask || node_isset(node, *nmask)) { > + mpol_cond_put(pol); > + page = alloc_pages_exact_node(node, gfp, order); > + if (unlikely(!page && > + read_mems_allowed_retry(cpuset_mems_cookie))) > + goto retry_cpuset; > + return page; > + } > + } > + mpol_cond_put(pol); > + /* > + * if current node is not part of node mask, try > + * the allocation from any node, and we can do retry > + * in that case. > + */ > + return alloc_pages_vma(gfp, order, vma, addr, node); > +}
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org> To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name>, David Rientjes <rientjes@google.com>, Vlastimil Babka <vbabka@suse.cz>, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V3] mm/thp: Allocate transparent hugepages on local node Date: Fri, 16 Jan 2015 16:02:04 -0800 [thread overview] Message-ID: <20150116160204.544e2bcf9627f5a4043ebf8d@linux-foundation.org> (raw) In-Reply-To: <1421393196-20915-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> On Fri, 16 Jan 2015 12:56:36 +0530 "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote: > This make sure that we try to allocate hugepages from local node if > allowed by mempolicy. If we can't, we fallback to small page allocation > based on mempolicy. This is based on the observation that allocating pages > on local node is more beneficial than allocating hugepages on remote node. The changelog is a bit incomplete. It doesn't describe the current behaviour, nor what is wrong with it. What are the before-and-after effects of this change? And what might be the user-visible effects? > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -2030,6 +2030,46 @@ retry_cpuset: > return page; > } > > +struct page *alloc_hugepage_vma(gfp_t gfp, struct vm_area_struct *vma, > + unsigned long addr, int order) alloc_pages_vma() is nicely documented. alloc_hugepage_vma() is not documented at all. This makes it a bit had for readers to work out the difference! Is it possible to scrunch them both into the same function? Probably too messy? > +{ > + struct page *page; > + nodemask_t *nmask; > + struct mempolicy *pol; > + int node = numa_node_id(); > + unsigned int cpuset_mems_cookie; > + > +retry_cpuset: > + pol = get_vma_policy(vma, addr); > + cpuset_mems_cookie = read_mems_allowed_begin(); > + > + if (pol->mode != MPOL_INTERLEAVE) { > + /* > + * For interleave policy, we don't worry about > + * current node. Otherwise if current node is > + * in nodemask, try to allocate hugepage from > + * current node. Don't fall back to other nodes > + * for THP. > + */ This code isn't "interleave policy". It's everything *but* interleave policy. Comment makes no sense! > + nmask = policy_nodemask(gfp, pol); > + if (!nmask || node_isset(node, *nmask)) { > + mpol_cond_put(pol); > + page = alloc_pages_exact_node(node, gfp, order); > + if (unlikely(!page && > + read_mems_allowed_retry(cpuset_mems_cookie))) > + goto retry_cpuset; > + return page; > + } > + } > + mpol_cond_put(pol); > + /* > + * if current node is not part of node mask, try > + * the allocation from any node, and we can do retry > + * in that case. > + */ > + return alloc_pages_vma(gfp, order, vma, addr, node); > +} -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2015-01-17 0:02 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-01-16 7:26 [PATCH V3] mm/thp: Allocate transparent hugepages on local node Aneesh Kumar K.V 2015-01-16 7:26 ` Aneesh Kumar K.V 2015-01-16 12:27 ` Kirill A. Shutemov 2015-01-16 12:27 ` Kirill A. Shutemov 2015-01-16 20:01 ` Vlastimil Babka 2015-01-16 20:01 ` Vlastimil Babka 2015-01-17 0:02 ` Andrew Morton [this message] 2015-01-17 0:02 ` Andrew Morton 2015-01-17 7:15 ` Davidlohr Bueso 2015-01-17 7:15 ` Davidlohr Bueso 2015-01-18 15:50 ` Aneesh Kumar K.V 2015-01-18 15:50 ` Aneesh Kumar K.V 2015-01-18 15:48 ` Aneesh Kumar K.V 2015-01-18 15:48 ` Aneesh Kumar K.V 2015-01-19 16:27 ` Vlastimil Babka 2015-01-19 16:27 ` Vlastimil Babka 2015-01-20 5:52 ` Aneesh Kumar K.V 2015-01-20 5:52 ` Aneesh Kumar K.V 2015-01-20 9:08 ` Vlastimil Babka 2015-01-20 9:08 ` Vlastimil Babka 2015-01-21 11:28 ` Vlastimil Babka 2015-01-21 11:28 ` Vlastimil Babka
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