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Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.7.2 Subject: Re: [PATCH v2 3/4] mm: hugetlb: change to return bool for isolate_hugetlb() To: Mike Kravetz , SeongJae Park Cc: akpm@linux-foundation.org, torvalds@linux-foundation.org, hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev, shakeelb@google.com, muchun.song@linux.dev, naoya.horiguchi@nec.com, linmiaohe@huawei.com, david@redhat.com, osalvador@suse.de, willy@infradead.org, damon@lists.linux.dev, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20230214180324.71585-1-sj@kernel.org> <20230214180708.71645-1-sj@kernel.org> From: Baolin Wang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: dij8kpszpy4gccd4p6q86f3xzphjmz9e X-Rspam-User: X-Rspamd-Queue-Id: 3472B40004 X-Rspamd-Server: rspam06 X-HE-Tag: 1676423210-185876 X-HE-Meta: U2FsdGVkX1+ykyvCcJvhmCR6oUb/PBzdVjxR/v2S3Vn+c3+DJUj/494czdHAjFMLP7TVv7g/KpPMlrhP10vSEMV/YLenSXaUFIscYP+oZm+QmvC3IAkeLwymE2hjtWqq5EDZMSribCkkRb3SMjxHU4QTQxlkrBp/KmMP0QSJg/H+7h2wylHewUeKdKtBoIjiAPNkxsVKabx9Hi8A66Scj2GllvNvVFf5TpiEBSgvxdZQq9Ispa/XoZueNJ8hD43IFiPf0YDBeP0WBEbQEFyaxYczIlW6evKy+y+IOxH3/GtByTQ1KaMVmbNSpXNTAHeXwCVYdpp40Xsx+v0gpJiayH4c/1oCti1qi2zemYBvfFKXpTwVQ4viwwvzkrsw/P88uqgRO4Eg+yIQU8NCoAniM0ddd6f3uCygBLRHXSenKiIurVJ5cROJGYEwCMzyxbyhku0uWF6hO7PVabIgXUea2KTLh44C78zKe0C6I8KIeJfQJLYX6jLtUXnNu5e3GnwGrN4I3x4DTT5BjdRlo+8MiccGjtDySijPYHVDrjwclDhnYQv8DW3qdIZeDh32ZMVCBLQpyWJbx1WPJKrRdtiHpIErkiUc4g8IAEfwEe8ERkYtPWfGEZFSaZyHU7fcqEC832nb+Rs40uTK7b1YtQGE5UHcqCon+kOfRJqcq464pj+cAAaEk2FDULM+NMg1ho6IyEC5oDxNP266ofwnKBSs5XMnRCPeALM7tqbKW8Hfq+i6eKO8WZEh8X54jRkRaGtvXEoFFM7MmiiWotw4xKI7h/+9KQcdrUPUYAHvX1d2V8wmmisKBDlFDbH6bx+FOe/OP9nheb4YDYp37ZRDo4eFzxJViOczA5Mttf0HgV+o/+tt1CfEgyKEuuY/tLwx3AT8wv0dacln6yVBbL32JnJJfa5R/bZbPqzcChkhGxgVmtKzSH0AHPdhS7JUJYqTwGjrkGCTS5vJxrJj0Did50W PkMAp/H9 6gzfoGk8gGC46UNWn08G7jiClYmRR1ZVsiIxz8hWJbHMrTTsZRoibJ7t1+8yCSJp8ryOcamgOG/rZDuHUasSFyKBqu9zIXNQhUkdx4ufeBaNRK8VbtrRPEZ0Z7R1sCnTgasHijS6ObilgJ4K7cGYkkwDpojw7McUi/EksFcBcFYW5ap58IFXefN37NDIHc35CGaeSsTCeRZDwyUip/6DXHyLmrGknp6F6ICwifg3A6AKH2vE= 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 2/15/2023 2:21 AM, Mike Kravetz wrote: > On 02/14/23 18:07, SeongJae Park wrote: >> On Tue, 14 Feb 2023 18:03:24 +0000 SeongJae Park wrote: >> >>> On Tue, 14 Feb 2023 21:59:31 +0800 Baolin Wang wrote: >>> >>>> Now the isolate_hugetlb() only returns 0 or -EBUSY, and most users did not >>>> care about the negative value, thus we can convert the isolate_hugetlb() >>>> to return a boolean value to make code more clear when checking the >>>> hugetlb isolation state. Moreover converts 2 users which will consider >>>> the negative value returned by isolate_hugetlb(). >>>> >>>> No functional changes intended. >>>> >>>> Signed-off-by: Baolin Wang >>>> --- >>>> include/linux/hugetlb.h | 6 +++--- >>>> mm/hugetlb.c | 12 ++++++++---- >>>> mm/memory-failure.c | 2 +- >>>> mm/mempolicy.c | 2 +- >>>> mm/migrate.c | 2 +- >>>> 5 files changed, 14 insertions(+), 10 deletions(-) >>>> >>>> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h >>>> index df6dd624ccfe..5f5e4177b2e0 100644 >> [...] >>>> diff --git a/mm/migrate.c b/mm/migrate.c >>>> index 53010a142e7f..c5136fa48638 100644 >>>> --- a/mm/migrate.c >>>> +++ b/mm/migrate.c >>>> @@ -2128,7 +2128,7 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, >>>> if (PageHead(page)) { >>>> err = isolate_hugetlb(page_folio(page), pagelist); >>>> if (!err) >>>> - err = 1; >>>> + err = -EBUSY; >>> >>> Again, I think this is confusing. 'err' is 'bool', not 'int'. >> >> I mean, 'err' is not 'bool' but 'int', sorry. See? This confuses me ;) >> > > Yes, > in the case here (and elsewhere) I like David's suggestion of using a separate > bool such as 'isolated' to capture the return value of the isolate function. > Then, the statement: > > err = isolated ? 0 : -EBUSY; > > would be pretty clear. Yes, much better, will do. Thanks.