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[174.93.89.182]) by smtp.gmail.com with ESMTPSA id z20sm17078830qki.93.2021.02.08.19.02.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 08 Feb 2021 19:02:35 -0800 (PST) From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Matthew Wilcox , Linus Torvalds , Kirill Tkhai , Mike Rapoport , David Gibson , Kirill Shutemov , Christoph Hellwig , Miaohe Lin , Gal Pressman , Jason Gunthorpe , Jann Horn , peterx@redhat.com, Jan Kara , Wei Zhang , Mike Kravetz , Andrea Arcangeli , Andrew Morton Subject: [PATCH v4 2/5] hugetlg: Break earlier in add_reservation_in_range() when we can Date: Mon, 8 Feb 2021 22:02:26 -0500 Message-Id: <20210209030229.84991-3-peterx@redhat.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210209030229.84991-1-peterx@redhat.com> References: <20210209030229.84991-1-peterx@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org All the regions maintained in hugetlb reserved map is inclusive on "from" but exclusive on "to". We can break earlier even if rg->from==t because it already means no possible intersection. This does not need a Fixes in all cases because when it happens (rg->from==t) we'll not break out of the loop while we should, however the next thing we'd do is still add the last file_region we'd need and quit the loop in the next round. So this change is not a bugfix (since the old code should still run okay iiuc), but we'd better still touch it up to make it logically sane. Reviewed-by: Mike Kravetz Reviewed-by: Miaohe Lin Signed-off-by: Peter Xu --- mm/hugetlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index ec8e29c805fe..71ccec5c3817 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -387,7 +387,7 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t, /* When we find a region that starts beyond our range, we've * finished. */ - if (rg->from > t) + if (rg->from >= t) break; /* Add an entry for last_accounted_offset -> rg->from, and -- 2.26.2