From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f43.google.com (mail-wm0-f43.google.com [74.125.82.43]) by kanga.kvack.org (Postfix) with ESMTP id C6EFD6B0005 for ; Fri, 19 Feb 2016 08:46:12 -0500 (EST) Received: by mail-wm0-f43.google.com with SMTP id g62so71716861wme.0 for ; Fri, 19 Feb 2016 05:46:12 -0800 (PST) Received: from mail-wm0-x231.google.com (mail-wm0-x231.google.com. [2a00:1450:400c:c09::231]) by mx.google.com with ESMTPS id es11si17961734wjb.139.2016.02.19.05.46.10 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 19 Feb 2016 05:46:10 -0800 (PST) Received: by mail-wm0-x231.google.com with SMTP id a4so71411376wme.1 for ; Fri, 19 Feb 2016 05:46:10 -0800 (PST) From: Michal Nazarewicz Subject: Re: [PATCH 1/2] mm: cma: split out in_cma check to separate function In-Reply-To: <1455869524-13874-1-git-send-email-rabin.vincent@axis.com> References: <1455869524-13874-1-git-send-email-rabin.vincent@axis.com> Date: Fri, 19 Feb 2016 14:46:08 +0100 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Rabin Vincent , linux@arm.linux.org.uk Cc: akpm@linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Rabin Vincent On Fri, Feb 19 2016, Rabin Vincent wrote: > Split out the logic in cma_release() which checks if the page is in the > contiguous area to a new function which can be called separately. ARM > will use this. > > Signed-off-by: Rabin Vincent > --- > include/linux/cma.h | 12 ++++++++++++ > mm/cma.c | 27 +++++++++++++++++++-------- > 2 files changed, 31 insertions(+), 8 deletions(-) > > diff --git a/include/linux/cma.h b/include/linux/cma.h > index 29f9e77..6e7fd2d 100644 > --- a/include/linux/cma.h > +++ b/include/linux/cma.h > @@ -27,5 +27,17 @@ extern int cma_init_reserved_mem(phys_addr_t base, phy= s_addr_t size, > unsigned int order_per_bit, > struct cma **res_cma); > extern struct page *cma_alloc(struct cma *cma, size_t count, unsigned in= t align); > + > extern bool cma_release(struct cma *cma, const struct page *pages, unsig= ned int count); > +#ifdef CONFIG_CMA > +extern bool in_cma(struct cma *cma, const struct page *pages, > + unsigned int count); > +#else > +static inline bool in_cma(struct cma *cma, const struct page *pages, > + unsigned int count) > +{ > + return false; > +} > +#endif > + > #endif > diff --git a/mm/cma.c b/mm/cma.c > index ea506eb..55cda16 100644 > --- a/mm/cma.c > +++ b/mm/cma.c > @@ -426,6 +426,23 @@ struct page *cma_alloc(struct cma *cma, size_t count= , unsigned int align) > return page; > } >=20=20 > +bool in_cma(struct cma *cma, const struct page *pages, unsigned int coun= t) Should it instead take pfn as an argument instead of a page? IIRC page_to_pfn may be expensive on some architectures and with this patch, cma_release will call it twice. Or maybe in_cma could return a pfn, something like (error checking stripped): unsigned long pfn in_cma(struct cma *cma, const struct page *page, unsgined count) { unsigned long pfn =3D page_to_pfn(page); if (pfn < cma->base_pfn || pfn >=3D cma->base_pfn + cma->count) return 0; VM_BUG_ON(pfn + count > cma->base_pfn + cma->count); return pfn; } Is pfn =3D=3D 0 guaranteed to be invalid? > +{ > + unsigned long pfn; > + > + if (!cma || !pages) > + return false; > + > + pfn =3D page_to_pfn(pages); > + > + if (pfn < cma->base_pfn || pfn >=3D cma->base_pfn + cma->count) > + return false; > + > + VM_BUG_ON(pfn + count > cma->base_pfn + cma->count); > + > + return true; > +} > + > /** > * cma_release() - release allocated pages > * @cma: Contiguous memory region for which the allocation is performe= d. > @@ -440,18 +457,12 @@ bool cma_release(struct cma *cma, const struct page= *pages, unsigned int count) > { > unsigned long pfn; >=20=20 > - if (!cma || !pages) > - return false; > - > pr_debug("%s(page %p)\n", __func__, (void *)pages); >=20=20 > - pfn =3D page_to_pfn(pages); > - > - if (pfn < cma->base_pfn || pfn >=3D cma->base_pfn + cma->count) > + if (!in_cma(cma, pages, count)) > return false; >=20=20 > - VM_BUG_ON(pfn + count > cma->base_pfn + cma->count); > - > + pfn =3D page_to_pfn(pages); > free_contig_range(pfn, count); > cma_clear_bitmap(cma, pfn, count); > trace_cma_release(pfn, pages, count); > --=20 > 2.7.0 > --=20 Best regards Liege of Serenely Enlightened Majesty of Computer Science, =E3=83=9F=E3=83=8F=E3=82=A6 =E2=80=9Cmina86=E2=80=9D =E3=83=8A=E3=82=B6=E3= =83=AC=E3=83=B4=E3=82=A4=E3=83=84 -- 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: email@kvack.org