From: Roman Gushchin <guro@fb.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Mike Rapoport <rppt@kernel.org>, <linux-mm@kvack.org>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Rik van Riel <riel@surriel.com>, Michal Hocko <mhocko@kernel.org>,
<linux-kernel@vger.kernel.org>, <kernel-team@fb.com>
Subject: Re: [PATCH v2 1/2] mm: cma: allocate cma areas bottom-up
Date: Wed, 23 Dec 2020 08:35:37 -0800 [thread overview]
Message-ID: <20201223163537.GA4011967@carbon.DHCP.thefacebook.com> (raw)
In-Reply-To: <20201222200606.fe4444f1f0ba008ee9fda091@linux-foundation.org>
On Tue, Dec 22, 2020 at 08:06:06PM -0800, Andrew Morton wrote:
> On Mon, 21 Dec 2020 09:05:51 -0800 Roman Gushchin <guro@fb.com> wrote:
>
> > Subject: [PATCH v3 1/2] mm: cma: allocate cma areas bottom-up
>
> i386 allmodconfig:
>
> In file included from ./include/vdso/const.h:5,
> from ./include/linux/const.h:4,
> from ./include/linux/bits.h:5,
> from ./include/linux/bitops.h:6,
> from ./include/linux/kernel.h:11,
> from ./include/asm-generic/bug.h:20,
> from ./arch/x86/include/asm/bug.h:93,
> from ./include/linux/bug.h:5,
> from ./include/linux/mmdebug.h:5,
> from ./include/linux/mm.h:9,
> from ./include/linux/memblock.h:13,
> from mm/cma.c:24:
> mm/cma.c: In function ‘cma_declare_contiguous_nid’:
> ./include/uapi/linux/const.h:20:19: warning: conversion from ‘long long unsigned int’ to ‘phys_addr_t’ {aka ‘unsigned int’} changes value from ‘4294967296’ to ‘0’ [-Woverflow]
> #define __AC(X,Y) (X##Y)
> ^~~~~~
> ./include/uapi/linux/const.h:21:18: note: in expansion of macro ‘__AC’
> #define _AC(X,Y) __AC(X,Y)
> ^~~~
> ./include/linux/sizes.h:46:18: note: in expansion of macro ‘_AC’
> #define SZ_4G _AC(0x100000000, ULL)
> ^~~
> mm/cma.c:349:53: note: in expansion of macro ‘SZ_4G’
> addr = memblock_alloc_range_nid(size, alignment, SZ_4G,
> ^~~~~
>
I thought that (!memblock_bottom_up() && memblock_end >= SZ_4G + size)
can't be true on a 32-bit platform, so the whole if clause can be compiled out.
Maybe it's because memblock_end can be equal to SZ_4G and if the size == 0...
I have no better idea than wrapping everything into
#if BITS_PER_LONG > 32
#endif.
Thanks!
--
diff --git a/mm/cma.c b/mm/cma.c
index 4fe74c9d83b0..5d69b498603a 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -344,12 +344,14 @@ int __init cma_declare_contiguous_nid(phys_addr_t base,
* Avoid using first 4GB to not interfere with constrained zones
* like DMA/DMA32.
*/
+#if BITS_PER_LONG > 32
if (!memblock_bottom_up() && memblock_end >= SZ_4G + size) {
memblock_set_bottom_up(true);
addr = memblock_alloc_range_nid(size, alignment, SZ_4G,
limit, nid, true);
memblock_set_bottom_up(false);
}
+#endif
if (!addr) {
addr = memblock_alloc_range_nid(size, alignment, base,
next prev parent reply other threads:[~2020-12-23 16:36 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-17 20:12 [PATCH v2 1/2] mm: cma: allocate cma areas bottom-up Roman Gushchin
2020-12-17 20:12 ` [PATCH v2 2/2] memblock: do not start bottom-up allocations with kernel_end Roman Gushchin
2020-12-19 14:52 ` Wonhyuk Yang
2020-12-19 17:05 ` Roman Gushchin
2020-12-20 6:49 ` Mike Rapoport
2021-01-22 4:37 ` Thiago Jung Bauermann
2021-01-24 2:09 ` Andrew Morton
2021-01-24 7:34 ` Mike Rapoport
2021-01-26 0:30 ` Thiago Jung Bauermann
2021-02-08 23:58 ` Thiago Jung Bauermann
2021-02-28 4:18 ` Florian Fainelli
2021-02-28 9:00 ` Mike Rapoport
2021-02-28 18:19 ` Florian Fainelli
2021-02-28 23:08 ` Serge Semin
2021-03-01 3:50 ` Florian Fainelli
2021-03-01 9:22 ` Serge Semin
2021-03-02 4:09 ` Florian Fainelli
2021-03-02 13:26 ` Serge Semin
2021-03-02 4:19 ` [PATCH] MIPS: BMIPS: Reserve exception base to prevent corruption Florian Fainelli
2021-03-02 8:09 ` Mike Rapoport
2021-03-02 13:54 ` Serge Semin
2021-03-02 19:04 ` Roman Gushchin
2021-03-02 23:54 ` Thomas Bogendoerfer
2021-03-03 1:30 ` Florian Fainelli
2021-03-03 9:41 ` Thomas Bogendoerfer
2021-03-03 17:45 ` Maciej W. Rozycki
2021-03-03 18:15 ` Thomas Bogendoerfer
2021-03-03 21:50 ` Maciej W. Rozycki
2021-03-01 9:45 ` [PATCH v2 2/2] memblock: do not start bottom-up allocations with kernel_end Mike Rapoport
2021-03-02 3:55 ` Roman Gushchin
2021-03-02 13:08 ` Serge Semin
2021-03-23 18:19 ` [tip: x86/boot] x86/setup: Consolidate early memory reservations tip-bot2 for Mike Rapoport
2020-12-20 6:48 ` [PATCH v2 1/2] mm: cma: allocate cma areas bottom-up Mike Rapoport
2020-12-21 17:05 ` Roman Gushchin
2020-12-23 4:06 ` Andrew Morton
2020-12-23 16:35 ` Roman Gushchin [this message]
2020-12-23 22:10 ` Mike Rapoport
2020-12-28 19:36 ` Roman Gushchin
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